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diff --git a/4924-0.txt b/4924-0.txt new file mode 100644 index 0000000..c5a79d3 --- /dev/null +++ b/4924-0.txt @@ -0,0 +1,8267 @@ +*** START OF THE PROJECT GUTENBERG EBOOK 4924 *** + + + + +DRY-FARMING + +A SYSTEM OF AGRICULTURE FOR COUNTRIES UNDER LOW RAINFALL + +BY JOHN A. WIDTSOE, A.M., Ph. D + +PRESIDENT OF THE AGRICULTURAL COLLEGE OF UTAH + +NEW YORK + +1920 + + + + + + +TO + +LEAH + +THIS BOOK IS INSCRIBED + +JUNE 1, 1910 + + + + + + +PREFACE + + + + + +Nearly six tenths of the earth's land surface receive an annual +rainfall of less than twenty inches, and can be reclaimed for +agricultural purposes only by irrigation and dry-farming. A +perfected world-system of irrigation will convert about one tenth of +this vast area into an incomparably fruitful garden, leaving about +one half of the earth's land surface to be reclaimed, if at all, by +the methods of dry-farming. The noble system of modern agriculture +has been constructed almost wholly in countries of abundant +rainfall, and its applications are those demanded for the +agricultural development of humid regions. Until recently irrigation +was given scant attention, and dry-farming, with its world problem +of conquering one half of the earth, was not considered. These facts +furnish the apology for the writing of this book. + +One volume, only, in this world of many books, and that less than a +year old, is devoted to the exposition of the accepted dry-farm +practices of to-day. + +The book now offered is the first attempt to assemble and organize +the known facts of science in their relation to the production of +plants, without irrigation, in regions of limited rainfall. The +needs of the actual farmer, who must understand the principles +before his practices can be wholly satisfactory, have been kept in +view primarily; but it is hoped that the enlarging group of dry-farm +investigators will also be helped by this presentation of the +principles of dry-farming. The subject is now growing so rapidly +that there will soon be room for two classes of treatment: one for +the farmer, and one for the technical student. + +This book has been written far from large libraries, and the +material has been drawn from the available sources. Specific +references are not given in the text, but the names of investigators +or institutions are found with nearly all statements of fact. The +files of the Experiment Station Record and Der Jahresbericht der +Agrikultur Chemie have taken the place of the more desirable +original publications. Free use has been made of the publications of +the experiment stations and the United States Department of +Agriculture. Inspiration and suggestions have been sought and found +constantly in the works of the princes of American soil +investigation, Hilgard of California and King of Wisconsin. I am +under deep obligation, for assistance rendered, to numerous friends +in all parts of the country, especially to Professor L. A. Merrill, +with whom I have collaborated for many years in the study of the +possibilities of dry-farming in Western America. + +The possibilities of dry-farming are stupendous. In the strength of +youth we may have felt envious of the great ones of old; of Columbus +looking upon the shadow of the greatest continent; of Balboa +shouting greetings to the resting Pacific; of Father Escalante, +pondering upon the mystery of the world, alone, near the shores of +America's Dead Sea. We need harbor no such envyings, for in the +conquest of the nonirrigated and nonirrigable desert are offered as +fine opportunities as the world has known to the makers and shakers +of empires. We stand before an undiscovered land; through the +restless, ascending currents of heated desert air the vision comes +and goes. With striving eyes the desert is seen covered with +blossoming fields, with churches and homes and schools, and, in the +distance, with the vision is heard the laughter of happy children. + +The desert will be conquered. + +JOHN A. WIDTSOE. + +June 1, 1910. + + + + + + +CHAPTER I + +INTRODUCTION + +DRY-FARMING DEFINED + + + + + +Dry-farming, as at present understood, is the profitable production +of useful crops, without irrigation, on lands that receive annually +a rainfall of 20 inches or less. In districts of torrential rains, +high winds, unfavorable distribution of the rainfall, or other +water-dissipating factors, the term "dry-farming" is also properly +applied to farming without irrigation under an annual precipitation +of 25 or even 30 inches. There is no sharp demarcation between +dry-and humid-farming. + +When the annual precipitation is under 20 inches, the methods of +dry-farming are usually indispensable. When it is over 30 inches, +the methods of humid-farming are employed; in places where the +annual precipitation is between 20 and 30 inches, the methods to be +used depend chiefly on local conditions affecting the conservation +of soil moisture. Dry-farming, however, always implies farming under +a comparatively small annual rainfall. + +The term "dry-farming" is, of course, a misnomer. In reality it is +farming under drier conditions than those prevailing in the +countries in which scientific agriculture originated. Many +suggestions for a better name have been made. "Scientific +agriculture" has-been proposed, but all agriculture should be +scientific, and agriculture without irrigation in an arid country +has no right to lay sole claim to so general a title. "Dry-land +agriculture," which has also been suggested, is no improvement over +"dry-farming," as it is longer and also carries with it the idea of +dryness. Instead of the name "dry-farming" it would, perhaps, be +better to use the names, "arid-farming." "semiarid-farming," +"humid-farming," and "irrigation-farming," according to the climatic +conditions prevailing in various parts of the world. However, at the +present time the name "dry-farming" is in such general use that it +would seem unwise to suggest any change. It should be used with the +distinct understanding that as far as the word "dry" is concerned it +is a misnomer. When the two words are hyphenated, however, a +compound technical term--"dry-farming"--is secured which has a +meaning of its own, such as we have just defined it to be; and +"dry-farming," therefore, becomes an addition to the lexicon. + +Dry-versus humid-farming + +Dry-farming, as a distinct branch of agriculture, has for its +purpose the reclamation, for the use of man, of the vast unirrigable +"desert" or "semi-desert" areas of the world, which until recently +were considered hopelessly barren. The great underlying principles +of agriculture are the same the world over, yet the emphasis to be +placed on the different agricultural theories and practices must be +shifted in accordance with regional conditions. The agricultural +problem of first importance in humid regions is the maintenance of +soil fertility; and since modern agriculture was developed almost +wholly under humid conditions, the system of scientific agriculture +has for its central idea the maintenance of soil fertility. In arid +regions, on the other hand, the conservation of the natural water +precipitation for crop production is the important problem; and a +new system of agriculture must therefore be constructed, on the +basis of the old principles, but with the conservation of the +natural precipitation as the central idea. The system of dry-farming +must marshal and organize all the established facts of science for +the better utilization, in plant growth, of a limited rainfall. The +excellent teachings of humid agriculture respecting the maintenance +of soil fertility will be of high value in the development of +dry-farming, and the firm establishment of right methods of +conserving and using the natural precipitation will undoubtedly have +a beneficial effect upon the practice of humid agriculture. + +The problems of dry-farming + +The dry-farmer, at the outset, should know with comparative accuracy +the annual rainfall over the area that he intends to cultivate. He +must also have a good acquaintance with the nature of the soil, not +only as regards its plant-food content, but as to its power to +receive and retain the water from rain and snow. In fact, a +knowledge of the soil is indispensable in successful dry-farming. +Only by such knowledge of the rainfall and the soil is he able to +adapt the principles outlined in this volume to his special needs. + +Since, under dry-farm conditions, water is the limiting factor of +production, the primary problem of dry-farming is the most effective +storage in the soil of the natural precipitation. Only the water, +safely stored in the soil within reach of the roots, can be used in +crop production. Of nearly equal importance is the problem of +keeping the water in the soil until it is needed by plants. During +the growing season, water may be lost from the soil by downward +drainage or by evaporation from the surface. It becomes necessary, +therefore, to determine under what conditions the natural +precipitation stored in the soil moves downward and by what means +surface evaporation may be prevented or regulated. The soil-water, +of real use to plants, is that taken up by the roots and finally +evaporated from the leaves. A large part of the water stored in the +soil is thus used. The methods whereby this direct draft of plants +on the soil-moisture may be regulated are, naturally, of the utmost +importance to the dry-farmer, and they constitute another vital +problem of the science of dry-farming. + +The relation of crops to the prevailing conditions of arid lands +offers another group of important dry-farm problems. Some plants use +much less water than others. Some attain maturity quickly, and in +that way become desirable for dry-farming. Still other crops, grown +under humid conditions, may easily be adapted to dry-farming +conditions, if the correct methods are employed, and in a few +seasons may be made valuable dry-farm crops. The individual +characteristics of each crop should be known as they relate +themselves to a low rainfall and arid soils. + +After a crop has been chosen, skill and knowledge are needed in the +proper seeding, tillage, and harvesting of the crop. Failures +frequently result from the want of adapting the crop treatment to +arid conditions. + +After the crop has been gathered and stored, its proper use is +another problem for the dry-farmer. The composition of dry-farm +crops is different from that of crops grown with an abundance of +water. Usually, dry-farm crops are much more nutritious and +therefore should command a higher price in the markets, or should be +fed to stock in corresponding proportions and combinations. + +The fundamental problems of dry-farming are, then, the storage in +the soil of a small annual rainfall; the retention in the soil of +the moisture until it is needed by plants; the prevention of the +direct evaporation of soil-moisture during; the growing season; the +regulation of the amount of water drawn from the soil by plants; the +choice of crops suitable for growth under arid conditions; the +application of suitable crop treatments, and the disposal of +dry-farm products, based upon the superior composition of plants +grown with small amounts of water. Around these fundamental problems +cluster a host of minor, though also important, problems. When the +methods of dry-farming are understood and practiced, the practice is +always successful; but it requires more intelligence, more implicit +obedience to nature's laws, and greater vigilance, than farming in +countries of abundant rainfall. + +The chapters that follow will deal almost wholly with the problems +above outlined as they present themselves in the construction of a +rational system of farming without irrigation in countries of +limited rainfall. + + + + + + +CHAPTER II + +THE THEORETICAL BASIS OF DRY-FARMING + + + + + +The confidence with which scientific investigators, familiar with +the arid regions, have attacked the problems of dry-farming rests +largely on the known relationship of the water requirements of +plants to the natural precipitation of rain and snow. It is a most +elementary fact of plant physiology that no plant can live and grow +unless it has at its disposal a sufficient amount of water. + +The water used by plants is almost entirely taken from the soil by +the minute root-hairs radiating from the roots. The water thus taken +into the plants is passed upward through the stem to the leaves, +where it is finally evaporated. There is, therefore, a more or less +constant stream of water passing through the plant from the roots to +the leaves. + +By various methods it is possible to measure the water thus taken +from the soil. While this process of taking water from the soil is +going on within the plant, a certain amount of soil-moisture is also +lost by direct evaporation from the soil surface. In dry-farm +sections, soil-moisture is lost only by these two methods; for +wherever the rainfall is sufficient to cause drainage from deep +soils, humid conditions prevail. + +Water for one pound dry matter + +Many experiments have been conducted to determine the amount of +water used in the production of one pound of dry plant substance. +Generally, the method of the experiments has been to grow plants in +large pots containing weighed quantities of soil. As needed, weighed +amounts of water were added to the pots. To determine the loss of +water, the pots were weighed at regular intervals of three days to +one week. At harvest time, the weight of dry matter was carefully +determined for each pot. Since the water lost by the pots was also +known, the pounds of water used for the production of every pound of +dry matter were readily calculated. + +The first reliable experiments of the kind were undertaken under +humid conditions in Germany and other European countries. From the +mass of results, some have been selected and presented in the +following table. The work was done by the famous German +investigators, Wollny, Hellriegel, and Sorauer, in the early +eighties of the last century. In every case, the numbers in the +table represent the number of pounds of water used for the +production of one pound of ripened dry substance: + + +Pounds Of Water For One Pound Of Dry Matter + + Wollny Hellreigel Sorauer +Wheat 338 459 +Oats 665 376 569 +Barley 310 431 +Rye 774 353 236 +Corn 233 +Buckwheat 646 363 +Peas 416 273 +Horsebeans 282 +Red clover 310 +Sunflowers 490 +Millet 447 + + +It is clear from the above results, obtained in Germany, that the +amount of water required to produce a pound of dry matter is not the +same for all plants, nor is it the same under all conditions for the +same plant. In fact, as will be shown in a later chapter, the water +requirements of any crop depend upon numerous factors, more or less +controllable. The range of the above German results is from 233 to +774 pounds, with an average of about 419 pounds of water for each +pound of dry matter produced. + +During the late eighties and early nineties, King conducted +experiments similar to the earlier German experiments, to determine +the water requirements of crops under Wisconsin conditions. A +summary of the results of these extensive and carefully conducted +experiments is as follows:-- + + +Oats 385 +Barley 464 +Corn 271 +Peas 477 +Clover 576 +Potatoes 385 + + +The figures in the above table, averaging about 446 pounds, indicate +that very nearly the same quantity of water is required for the +production of crops in Wisconsin as in Germany. The Wisconsin +results tend to be somewhat higher than those obtained in Europe, +but the difference is small. + +It is a settled principle of science, as will be more fully +discussed later, that the amount of water evaporated from the soil +and transpired by plant leaves increases materially with an increase +in the average temperature during the growing season, and is much +higher under a clear sky and in districts where the atmosphere is +dry. Wherever dry-farming is likely to be practiced, a moderately +high temperature, a cloudless sky, and a dry atmosphere are the +prevailing conditions. It appeared probable therefore, that in arid +countries the amount of water required for the production of one +pound of dry matter would be higher than in the humid regions of +Germany and Wisconsin. To secure information on this subject, +Widtsoe and Merrill undertook, in 1900, a series of experiments in +Utah, which were conducted upon the plan of the earlier +experimenters. An average statement of the results of six years' +experimentation is given in the subjoined table, showing the number +of pounds of water required for one pound of dry matter on fertile +soils:-- + + +Wheat 1048 +Corn 589 +Peas 1118 +Sugar Beets 630 + + + +These Utah findings support strongly the doctrine that the amount of +water required for the production of each pound of dry matter is +very much larger under arid conditions, as in Utah, than under humid +conditions, as in Germany or Wisconsin. It must be observed, +however, that in all of these experiments the plants were supplied +with water in a somewhat wasteful manner; that is, they were given +an abundance of water, and used the largest quantity possible under +the prevailing conditions. No attempt of any kind was made to +economize water. The results, therefore, represent maximum results +and can be safely used as such. Moreover, the methods of +dry-farming, involving the storage of water in deep soils and +systematic cultivation, were not employed. The experiments, both in +Europe and America, rather represent irrigated conditions. There are +good reasons for believing that in Germany, Wisconsin, and Utah the +amounts above given can be materially reduced by the employment of +proper cultural methods. + +The water in the large bottle would be required to produce the grain +in the small bottle. + +In view of these findings concerning the water requirements of +crops, it cannot be far from the truth to say that, under average +cultural conditions, approximately 750 pounds of water are required +in an arid district for the production of one pound of dry matter. +Where the aridity is intense, this figure may be somewhat low, and +in localities of sub-humid conditions, it will undoubtedly be too +high. As a maximum average, however, for districts interested in +dry-farming, it can be used with safety. + +Crop-producing power of rainfall + +If this conclusion, that not more than 750 pounds of water are +required under ordinary dry-farm conditions for the production of +one pound of dry matter, be accepted, certain interesting +calculations can be made respecting the possibilities of +dry-farming. For example, the production of one bushel of wheat will +require 60 times 750, or 45,000 pounds of water. The wheat kernels, +however, cannot be produced without a certain amount of straw, which +under conditions of dry-farming seldom forms quite one half of the +weight of the whole plant. Let us say, however, that the weights of +straw and kernels are equal. Then, to produce one bushel of wheat, +with the corresponding quantity of straw, would require 2 times +45,000, or 90,000 pounds of water. This is equal to 45 tons of water +for each bushel of wheat. While this is a large figure, yet, in many +localities, it is undoubtedly well within the truth. In comparison +with the amounts of water that fall upon the land as rain, it does +not seem extraordinarily large. + +One inch of water over one acre of land weighs approximately 226,875 +pounds. or over 113 tons. If this quantity of water could be stored +in the soil and used wholly for plant production, it would produce, +at the rate of 45 tons of water for each bushel, about 2-1/2 bushels +of wheat. With 10 inches of rainfall, which up to the present seems +to be the lower limit of successful dry-farming, there is a maximum +possibility of producing 25 bushels of wheat annually. + +In the subjoined table, constructed on the basis of the discussion +of this chapter, the wheat-producing powers of various degrees of +annual precipitation are shown:-- + +One acre inch of water will produce 2-1/2 bushels of wheat. + +Ten acre inches of water will produce 25 bushels of wheat. + +Fifteen acre inches of water will produce 37-1/2 bushels of wheat. + +Twenty acre inches of water will produce 50 bushels of wheat. + +It must be distinctly remembered, however, that under no known +system of tillage can all the water that falls upon a soil be +brought into the soil and stored there for plant use. Neither is it +possible to treat a soil so that all the stored soil-moisture may be +used for plant production. Some moisture, of necessity, will +evaporate directly from the soil, and some may be lost in many other +ways. Yet, even under a rainfall of 12 inches, if only one half of +the water can be conserved, which experiments have shown to be very +feasible, there is a possibility of producing 30 bushels of wheat +per acre every other year, which insures an excellent interest on +the money and labor invested in the production of the crop. + +It is on the grounds outlined in this chapter that students of the +subject believe that ultimately large areas of the "desert" may be +reclaimed by means of dry-farming. The real question before the +dry-farmer is not, "Is the rainfall sufficient?" but rather, "Is it +possible so to conserve and use the rainfall as to make it available +for the production of profitable crops?" + + + + + + + +CHAPTER III + +DRY-FARM AREAS--RAINFALL + + + + + +The annual precipitation of rain and snow determines primarily the +location of dry-farm areas. As the rainfall varies, the methods of +dry-farming must be varied accordingly. Rainfall, alone, does not, +however, furnish a complete index of the crop-producing +possibilities of a country. + +The distribution of the rainfall, the amount of snow, the +water-holding power of the soil, and the various +moisture-dissipating causes, such as winds, high temperature, +abundant sunshine, and low humidity frequently combine to offset the +benefits of a large annual precipitation. Nevertheless, no one +climatic feature represents, on the average, so correctly +dry-farming possibilities as does the annual rainfall. Experience +has already demonstrated that wherever the annual precipitation is +above 15 inches, there is no need of crop failures, if the soils are +suitable and the methods of dry-farming are correctly employed. With +an annual precipitation of 10 to 15 inches, there need be very few +failures, if proper cultural precautions are taken. With our present +methods, the areas that receive less than 10 inches of atmospheric +precipitation per year are not safe for dry-farm purposes. What the +future will show in the reclamation of these deserts, without +irrigation, is yet conjectural. + +Arid, semiarid, and sub-humid + +Before proceeding to an examination of the areas in the United +States subject to the methods of dry-farming it may be well to +define somewhat more clearly the terms ordinarily used in the +description of the great territory involved in the discussion. + +The states lying west of the 100th meridian are loosely spoken of as +arid, semiarid, or sub-humid states. For commercial purposes no +state wants to be classed as arid and to suffer under the handicap +of advertised aridity. The annual rainfall of these states ranges +from about 3 to over 30 inches. + +In order to arrive at greater definiteness, it may be well to assign +definite rainfall values to the ordinarily used descriptive terms of +the region in question. It is proposed, therefore, that districts +receiving less than 10 inches of atmospheric precipitation annually, +be designated arid; those receiving between 10 and 20 inches, +semiarid; those receiving between 20 and 30 inches, sub-humid, and +those receiving over 30 inches, humid. It is admitted that even such +a classification is arbitrary, since aridity does not alone depend +upon the rainfall, and even under such a classification there is an +unavoidable overlapping. However, no one factor so fully represents +varying degrees of aridity as the annual precipitation, and there is +a great need for concise definitions of the terms used in describing +the parts of the country that come under dry-farming discussions. In +this volume, the terms "arid," "semiarid," "sub-humid" and "humid" +are used as above defined. + +Precipitation over the dry-farm territory + +Nearly one half of the United States receives 20 inches or less +rainfall annually; and that when the strip receiving between 20 and +30 inches is added, the whole area directly subject to reclamation +by irrigation or dry-farming is considerably more than one half (63 +per cent) of the whole area of the United States. + +Eighteen states are included in this area of low rainfall. The areas +of these, as given by the Census of 1900, grouped according to the +annual precipitation received, are shown below:-- + + +Arid to Semi-arid Group +Total Area Land Surface (Sq. Miles) + +Arizona 112,920 +California 156,172 +Colorado 103,645 +Idaho 84,290 +Nevada 109,740 +Utah 82,190 +Wyoming 97,545 +TOTAL 746,532 + +Semiarid to Sub-Humid Group + +Montana 145,310 +Nebraska 76,840 +New Mexico 112,460 +North Dakota 70,195 +Oregon 94,560 +South Dakota 76,850 +Washington 66,880 +TOTAL 653,095 + +Sub-Humid to Humid Group + +Kansas 81,700 +Minnesota 79,205 +Oklahoma 38,830 +Texas 262,290 +TOTAL 462,025 + +GRAND TOTAL 1,861,652 + + +The territory directly interested in the development of the methods +of dry-farming forms 63 per cent of the whole of the continental +United States, not including Alaska, and covers an area of 1,861,652 +square miles, or 1,191,457,280 acres. If any excuse were needed for +the lively interest taken in the subject of dry-farming, it is amply +furnished by these figures showing the vast extent of the country +interested in the reclamation of land by the methods of dry-farming. +As will be shown below, nearly every other large country possesses +similar immense areas under limited rainfall. + +Of the one billion, one hundred and ninety-one million, four hundred +and fifty-seven thousand, two hundred and eighty acres +(1,191,457,280) representing the dry-farm territory of the United +States, about 22 per cent, or a little more than one fifth, is +sub-humid and receives between 20 and 30 inches of rainfall, +annually; 61 per cent, or a little more than three fifths, is +semiarid and receives between 10 and 20 inches, annually, and about +17 per cent, or a little less than one fifth, is arid and receives +less than 10 inches of rainfall, annually. + +These calculations are based upon the published average rainfall +maps of the United States Weather Bureau. In the far West, and +especially over the so-called "desert" regions, with their sparse +population, meteorological stations are not numerous, nor is it easy +to secure accurate data from them. It is strongly probable that as +more stations are established, it will be found that the area +receiving less than 10 inches of rainfall annually is considerably +smaller than above estimated. In fact, the United States Reclamation +Service states that there are only 70,000,000 acres of desert-like +land; that is, land which does not naturally support plants suitable +for forage. This area is about one third of the lands which, so far +as known, at present receive less than 10 inches of rainfall, or +only about 6 per cent of the total dry-farming territory. + +In any case, the semiarid area is at present most vitally interested +in dry-farming. The sub-humid area need seldom suffer from drouth, +if ordinary well-known methods are employed; the arid area, +receiving less than 10 inches of rainfall, in all probability, can +be reclaimed without irrigation only by the development of more +suitable. methods than are known to-day. The semiarid area, which is +the special consideration of present-day dry-farming represents an +area of over 725,000,000 acres of land. Moreover, it must be +remarked that the full certainty of crops in the sub-humid regions +will come only with the adoption of dry-farming methods; and that +results already obtained on the edge of the "deserts" lead to the +belief that a large portion of the area receiving less than 10 +inches of rainfall, annually, will ultimately be reclaimed without +irrigation. + +Naturally, not the whole of the vast area just discussed could be +brought under cultivation, even under the most favorable conditions +of rainfall. A very large portion of the territory in question is +mountainous and often of so rugged a nature that to farm it would be +an impossibility. It must not be forgotten, however, that some of +the best dry-farm lands of the West are found in the small mountain +valleys, which usually are pockets of most fertile soil, under a +good supply of rainfall. The foothills of the mountains are almost +invariably excellent dry-farm lands. Newell estimates that +195,000,000 acres of land in the arid to sub-humid sections are +covered with a more or less dense growth of timber. This timbered +area roughly represents the mountainous and therefore the nonarable +portions of land. The same authority estimates that the desert-like +lands cover an area of 70,000,000 acres. Making the most liberal +estimates for mountainous and desert-like lands, at least one half +of the whole area, or about 600,000,000 acres, is arable land which +by proper methods may be reclaimed for agricultural purposes. +Irrigation when fully developed may reclaim not to exceed 5 per cent +of this area. From any point of view, therefore, the possibilities +involved in dry-farming in the United States are immense. + +Dry-farm area of the world + +Dry-farming is a world problem. Aridity is a condition met and to be +overcome upon every continent. McColl estimates that in Australia, +which is somewhat larger than the continental United States of +America, only one third of the whole surface receives above 20 +inches of rainfall annually; one third receives from 10 to 20 +inches, and one third receives less than lO inches. That is, about +1,267,000,000 acres in Australia are subject to reclamation by +dry-farming methods. This condition is not far from that which +prevails in the United States, and is representative of every +continent of the world. The following table gives the proportions of +the earth's land surface under various degrees of annual +precipitations:-- + + +Annual Precipitation Proportion of Earth's Land Surface +Under 10 inches 25.0 per cent +From 10 to 20 inches 30.0 per cent +From 20 to 40 inches 20.0 per cent +From 40 to 60 inches 11.0 per cent +From 60 to 80 inches 9.0 per cent +From 100 to 120 inches 4.0 per cent +From 120 to 160 inches 0.5 per cent +Above 160 inches 0.5 per cent +Total 100 per cent + + +Fifty-five per cent, or more than one half of the total land surface +of the earth, receives an annual precipitation of less than 20 +inches, and must be reclaimed, if at all, by dry-farming. At least +10 per cent more receives from 20 to 30 inches under conditions that +make dry-farming methods necessary. A total of about 65 per cent of +the earth's land surface is, therefore, directly interested in +dry-farming. With the future perfected development of irrigation +systems and practices, not more than 10 per cent will be reclaimed +by irrigation. Dry-farming is truly a problem to challenge the +attention of the race. + + + + + + +CHAPTER IV + +DRY-FARM AREAS.--GENERAL CLIMATIC FEATURES + + + + + +The dry-farm territory of the United States stretches from the +Pacific seaboard to the 96th parallel of longitude, and from the +Canadian to the Mexican boundary, making a total area of nearly +1,800,000 square miles. This immense territory is far from being a +vast level plain. On the extreme east is the Great Plains region of +the Mississippi Valley which is a comparatively uniform country of +rolling hills, but no mountains. At a point about one third of the +whole distance westward the whole land is lifted skyward by the +Rocky Mountains, which cross the country from south to northwest. +Here are innumerable peaks, canons, high table-lands, roaring +torrents, and quiet mountain valleys. West of the Rockies is the +great depression known as the Great Basin, which has no outlet to +the ocean. It is essentially a gigantic level lake floor traversed +in many directions by mountain ranges that are offshoots from the +backbone of the Rockies. South of the Great Basin are the high +plateaus, into which many great chasms are cut, the best known and +largest of which is the great Canon of the Colorado. North and east +of the Great Basin is the Columbia River Basin characterized by +basaltic rolling plains and broken mountain country. To the west, +the floor of the Great Basin is lifted up into the region of eternal +snow by the Sierra Nevada Mountains, which north of Nevada are known +as the Cascades. On the west, the Sierra Nevadas slope gently, +through intervening valleys and minor mountain ranges, into the +Pacific Ocean. It would be difficult to imagine a more diversified +topography than is possessed by the dry-farm territory of the United +States. + +Uniform climatic conditions are not to be expected over such a +broken country. The chief determining factors of climate--latitude, +relative distribution of land and water, elevation, prevailing +winds--swing between such large extremes that of necessity the +climatic conditions of different sections are widely divergent. +Dry-farming is so intimately related to climate that the typical +climatic variations must be pointed out. + +The total annual precipitation is directly influenced by the land +topography, especially by the great mountain ranges. On the east of +the Rocky Mountains is the sub-humid district, which receives from +20 to 30 inches of rainfall annually; over the Rockies themselves, +semiarid conditions prevail; in the Great Basin, hemmed in by the +Rockies on the east and the Sierra Nevadas on the west, more arid +conditions predominate; to the west, over the Sierras and down to +the seacoast, semiarid to sub-humid conditions are again found. + +Seasonal distribution of rainfall + +It is doubtless true that the total annual precipitation is the +chief factor in determining the success of dry-farming. However, the +distribution of the rainfall throughout the year is also of great +importance, and should be known by the farmer. A small rainfall, +coming at the most desirable season, will have greater +crop-producing power than a very much larger rainfall poorly +distributed. Moreover, the methods of tillage to be employed where +most of the precipitation comes in winter must be considerably +different from those used where the bulk of the precipitation comes +in the summer. The successful dry-farmer must know the average +annual precipitation, and also the average seasonal distribution of +the rainfall, over the land which he intends to dry-farm before he +can safely choose his cultural methods. + +With reference to the monthly distribution of the precipitation over +the dry-farm territory of the United States, Henry of the United +States Weather Bureau recognizes five distinct types; namely: (1) +Pacific, (2) Sub-Pacific, (3) Arizona, (4) the Northern Rocky +Mountain and Eastern Foothills, and (5) the Plains Type:-- + +_"The Pacific Type.--_This type is found in all of the territory +west of the Cascade and Sierra Nevada ranges, and also obtains in a +fringe of country to the eastward of the mountain summits. The +distinguishing characteristic of the Pacific type is a wet season, +extending from October to March, and a practically rainless summer, +except in northern California and parts of Oregon and Washington. +About half of the yearly precipitation comes in the months of +December, January, and February, the remaining half being +distributed throughout the seven months--September, October, +November, March, April, May, and June." + +_"Sub-Pacific Type.--_The term 'Sub-Pacific' has been given to that +type of rainfall which obtains over eastern Washington, Nevada, and +Utah. The influences that control the precipitation of this region +are much similar to those that prevail west of the Sierra Nevada and +Cascade ranges. There is not, however, as in the eastern type, a +steady diminution in the precipitation with the approach of spring, +but rather a culmination in the precipitation." + +_"Arizona Type.--_The Arizona Type, so called because it is more +fully developed in that territory than elsewhere, prevails over +Arizona, New Mexico, and a small portion of eastern Utah and Nevada. +This type differs from all others in the fact that about 35 per cent +of the rain falls in July and August. May and June are generally the +months of least rainfall." + +_"The Northern Rocky Mountain and Eastern Foothills Type.--_This +type is closely allied to that of the plains to the eastward, and +the bulk of the rain falls in the foothills of the region in April +and May; in Montana, in May and June." + +_"The Plains Type.--_This type embraces the greater part of the +Dakotas, Nebraska, Kansas; Oklahoma, the Panhandle of Texas, and all +the great corn and wheat states of the interior valleys. This region +is characterized by a scant winter precipitation over the northern +states and moderately heavy rains during the growing season. The. +bulk of the rains comes in May, June, and July." + +This classification emphasizes the great variation in distribution +of rainfall over the dry-farm territory of the country. West of the +Rocky Mountains the precipitation comes chiefly in winter and +spring, leaving the summers rainless; while east of the Rockies, the +winters are somewhat rainless and the precipitation comes chiefly in +spring and summer. The Arizona type stands midway between these +types. This variation in the distribution of the rainfall requires +that different methods be employed in storing and conserving the +rainfall for crop production. The adaptation of cultural methods to +the seasonal distribution of rainfall will be discussed hereafter. + +Snowfall + +Closely related to the distribution of the rainfall and the average +annual temperature is the snowfall. Wherever a relatively large +winter precipitation occurs, the dry-farmer is benefited if it comes +in the form of snow. The fall-planted seeds are better protected by +the snow; the evaporation is lower and it appears that the soil is +improved by the annual covering of snow. In any case, the methods of +culture are in a measure dependent upon the amount of snowfall and +the length of time that it lies upon the ground. + +Snow falls over most of the dry-farm territory, excepting the +lowlands of California, the immediate Pacific coast, and other +districts where the average annual temperature is high. The heaviest +snowfall is in the intermountain district, from the west slope of +the Sierra Nevadas to the east slope of the Rockies. The degree of +snowfall on the agricultural lands is very variable and dependent +upon local conditions. Snow falls upon all the high mountain ranges. + +Temperature + +With the exceptions of portions of California, Arizona, and Texas +the average annual surface temperature of the dry-farm territory of +the United States ranges from 40 deg to 55 deg F. The average is not +far from 45 deg F. This places most of the dry-farm territory in the +class of cold regions, though a small area on the extreme east +border may be classed as temperate, and parts of California and +Arizona as warm. The range in temperature from the highest in summer +to the lowest in winter is considerable, but not widely different +from other similar parts of the United States. The range is greatest +in the interior mountainous districts, and lowest along the +seacoast. The daily range of the highest and lowest temperatures for +any one day is generally higher over dry-farm sections than over +humid districts. In the Plateau regions of the semiarid country the +average daily variation is from 30 to 35 deg F., while east of the +Mississippi it is only about 20 deg F. This greater daily range is +chiefly due to the clear skies and scant vegetation which facilitate +excessive warming by day and cooling by night. + +The important temperature question for the dry-farmer is whether the +growing season is sufficiently warm and long to permit the maturing +of crops. There are few places, even at high altitudes in the region +considered, where the summer temperature is so low as to retard the +growth of plants. Likewise, the first and last killing frosts are +ordinarily so far apart as to allow an ample growing season. It must +be remembered that frosts are governed very largely by local +topographic features, and must be known from a local point of view. +It is a general law that frosts are more likely to occur in valleys +than on hillsides, owing to the downward drainage of the cooled air. +Further, the danger of frost increases with the altitude. In +general, the last killing frost in spring over the dry-farm +territory varies from March 15 to May 29, and the first killing +frost in autumn from September 15 to November 15. These limits +permit of the maturing of all ordinary farm crops, especially the +grain crops. + +Relative humidity + +At a definite temperature, the atmosphere can hold only a certain +amount of water vapor. When the air can hold no more, it is said to +be saturated. When it is not saturated, the amount of water vapor +actually held by the air is expressed in percentages of the quantity +required for saturation. A relative humidity of 100 per cent means +that the air is saturated; of 50 per cent, that it is only one half +saturated. The drier the air is, the more rapidly does the water +evaporate into it. To the dry-farmer, therefore, the relative +humidity or degree of dryness of the air is of very great +importance. According to Professor Henry, the chief characteristics +of the geographic distribution of relative humidity in the United +States are as follows:-- + +(1) Along the coasts there is a belt of high humidity at all +seasons, the percentage of saturation ranging from 75 to 80 per +cent. + +(2) Inland, from about the 70th meridian eastward to the Atlantic +coast, the amount varies between 70 and 75 per cent. + +(3) The dry region is in the Southwest, where the average annual +value is not over 50 per cent. In this region are included Arizona, +New Mexico, western Colorado, and the greater portion of both Utah +and Nevada. The amount of annual relative humidity in the remaining +portion of the elevated district, between the 100th meridian on the +east to the Sierra Nevada and the Cascades on the west, varies +between 55 and 65 per cent. In July, August, and September, the mean +values in the Southwest sink as low as 20 to 30 per cent, while +along the Pacific coast districts they continue about 80 per cent +the year round. In the Atlantic coast districts, and generally east +from the Mississippi River, the variation from month to month is not +great. April is probably the driest month of the year. + +The air of the dry-farm territory, therefore, on the whole, contains +considerably less than two thirds the amount of moisture carried by +the air of the humid states. This means that evaporation from plant +leaves and soil surfaces will go on more rapidly in semiarid than in +humid regions. Against this danger, which cannot he controlled, the +dry-farmer must take special precautions. + +Sunshine + +The amount of sunshine in a dry-farm section is also of importance. +Direct sunshine promotes plant growth, but at the same time it +accelerates the evaporation of water from the soil. The whole +dry-farm territory receives more sunshine than do the humid +sections. In fact, the amount of sunshine may roughly be said to +increase as the annual rainfall decreases. Over the larger part of +the arid and semiarid sections the sun shines over 70 per cent of +the time. + +Winds + +The winds of any locality, owing to their moisture-dissipating +power play an important part in the success of dry-farming. A +persistent wind will offset much of the benefit of a heavy rainfall +and careful cultivation. While great general laws have been +formulated regarding the movements of the atmosphere, they are of +minor value in judging the effect of wind on any farming district. +Local observations, however, may enable the farmer to estimate the +probable effect of the winds and thus to formulate proper cultural +means of protection. In general, those living in a district are able +to describe it without special observations as windy or quiet. In +the dry-farm territory of the United States the one great region of +relatively high and persistent winds is the Great Plains region east +of the Rocky Mountains. Dry-farmers in that section will of +necessity be obliged to adopt cultural methods that will prevent the +excessive evaporation naturally induced by the unhindered wind, and +the possible blowing of well-tilled fallow land. + +Summary + +The dry-farm territory is characterized by a low rainfall, averaging +between 10 and 20 inches, the distribution of which falls into two +distinct types: a heavy winter and spring with a light summer +precipitation, and a heavy spring and summer with a light winter +precipitation. Snow falls over most of the territory, but does not +lie long outside of the mountain states. The whole dry-farm +territory may be classed as temperate to cold; relatively high and +persistent winds blow only over the Great Plains, though local +conditions cause strong regular winds in many other places; the air +is dry and the sunshine is very abundant. In brief, little water +falls upon the dry-farm territory, and the climatic factors are of a +nature to cause rapid evaporation. + +In view of this knowledge, it is not surprising that thousands of +farmers, employing, often carelessly agricultural methods developed +in humid sections, have found only hardships and poverty on the +present dry-farm empire of the United States. + +Drouth + +Drouth is said to be the arch enemy of the dry-farmer, but few agree +upon its meaning. For the purposes of this volume, drouth may be +defined as a condition under which crops fail to mature because of +an insufficient supply of water. Providence has generally been +charged with causing drouths, but under the above definition, man is +usually the cause. Occasionally, relatively dry years occur, but +they are seldom dry enough to cause crop failures if proper methods +of farming have been practiced. There are four chief causes of +drouth: (1) Improper or careless preparation of the soil; (2) +failure to store the natural precipitation in the soil; (3) failure +to apply proper cultural methods for keeping the moisture in the +soil until needed by plants, and (4) sowing too much seed for the +available soil-moisture. + +Crop failures due to untimely frosts, blizzards, cyclones, +tornadoes, or hail may perhaps be charged to Providence, but the +dry-farmer must accept the responsibility for any crop injury +resulting from drouth. A fairly accurate knowledge of the climatic +conditions of the district, a good understanding of the principles +of agriculture without irrigation under a low rainfall, and a +vigorous application of these principles as adapted to the local +climatic conditions will make dry-farm failures a rarity. + + + + + + +CHAPTER V + +DRY-FARM SOILS + + + + + +Important as is the rainfall in making dry-farming successful, it is +not more so than the soils of the dry-farms. On a shallow soil, or +on one penetrated with gravel streaks, crop failures are probable +even under a large rainfall; but a deep soil of uniform texture, +unbroken by gravel or hardpan, in which much water may be stored, +and which furnishes also an abundance of feeding space for the +roots, will yield large crops even under a very small rainfall. +Likewise, an infertile soil, though it be deep, and under a large +precipitation, cannot be depended on for good crops; but a fertile +soil, though not quite so deep, nor under so large a rainfall, will +almost invariably bring large crops to maturity. + +A correct understanding of the soil, from the surface to a depth of +ten feet, is almost indispensable before a safe Judgment can be +pronounced upon the full dry-farm possibilities of a district. +Especially is it necessary to know (a) the depth, (b) the uniformity +of structure, and (c) the relative fertility of the soil, in order +to plan an intelligent system of farming that will be rationally +adapted to the rainfall and other climatic factors. + +It is a matter of regret that so much of our information concerning +the soils of the dry-farm territory of the United States and other +countries has been obtained according to the methods and for the +needs of humid countries, and that, therefore, the special knowledge +of our arid and semiarid soils needed for the development of +dry-farming is small and fragmentary. What is known to-day +concerning the nature of arid soils and their relation to cultural +processes under a scanty rainfall is due very largely to the +extensive researches and voluminous writings of Dr. E. W. Hilgard, +who for a generation was in charge of the agricultural work of the +state of California. Future students of arid soils must of necessity +rest their investigations upon the pioneer work done by Dr. Hilgard. +The contents of this chapter are in a large part gathered from +Hilgard's writings. + +The formation of soils + +"Soil is the more or less loose and friable material in which, by +means of their roots, plants may or do find a foothold and +nourishment, as well as other conditions of growth." Soil is formed +by a complex process, broadly known as _weathering, _from the rocks +which constitute the earth's crust. Soil is in fact only pulverized +and altered rock. The forces that produce soil from rocks are of two +distinct classes, _physical and chemical. _The physical agencies of +soil production merely cause a pulverization of the rock; the +chemical agencies, on the other hand, so thoroughly change the +essential nature of the soil particles that they are no longer like +the rock from which they were formed. + +Of the physical agencies, _temperature changes _are first in order +of time, and perhaps of first importance. As the heat of the day +increases, the rock expands, and as the cold night approaches, +contracts. This alternate expansion and contraction, in time, cracks +the surfaces of the rocks. Into the tiny crevices thus formed water +enters from the falling snow or rain. When winter comes, the water +in these cracks freezes to ice, and in so doing expands and widens +each of the cracks. As these processes are repeated from day to day, +from year to year, and from generation to generation, the surfaces +of the rocks crumble. The smaller rocks so formed are acted upon by +the same agencies, in the same manner, and thus the process of +pulverization goes on. + +It is clear, then, that the second great agency of soil formation, +which always acts in conjunction with temperature changes, is +_freezing water. _The rock particles formed in this manner are often +washed down into the mountain valleys, there caught by great rivers, +ground into finer dust, and at length deposited in the lower +valleys. _Moving water _thus becomes another physical agency of soil +production. Most of the soils covering the great dry-farm territory +of the United States and other countries have been formed in this +way. + +In places, glaciers moving slowly down the canons crush and grind +into powder the rock over which they pass and deposit it lower down +as soils. In other places, where strong winds blow with frequent +regularity, sharp soil grains are picked up by the air and hurled +against the rocks, which, under this action, are carved into +fantastic forms. In still other places, the strong winds carry soil +over long distances to be mixed with other soils. Finally, on the +seashore the great waves dashing against the rocks of the coast +line, and rolling the mass of pebbles back and forth, break and +pulverize the rock until soil is formed._ Glaciers, winds, _and +_waves _are also, therefore, physical agencies of soil formation. + +It may be noted that the result of the action of all these agencies +is to form a rock powder, each particle of which preserves the +composition that it had while it was a constituent part of the rock. +It may further be noted that the chief of these soil-forming +agencies act more vigorously in arid than in humid sections. Under +the cloudless sky and dry atmosphere of regions of limited rainfall, +the daily and seasonal temperature changes are much greater than in +sections of greater rainfall. Consequently the pulverization of +rocks goes on most rapidly in dry-farm districts. Constant heavy +winds, which as soil formers are second only to temperature changes +and freezing water, are also usually more common in arid than in +humid countries. This is strikingly shown, for instance, on the +Colorado desert and the Great Plains. + +The rock powder formed by the processes above described is +continually being acted upon by agencies, the effect of which is to +change its chemical composition. Chief of these agencies is _water, +_which exerts a solvent action on all known substances. Pure water +exerts a strong solvent action, but when it has been rendered impure +by a variety of substances, naturally occurring, its solvent action +is greatly increased. + +The most effective water impurity, considering soil formation, is +the gas, _carbon dioxid. _This gas is formed whenever plant or +animal substances decay, and is therefore found, normally, in the +atmosphere and in soils. Rains or flowing water gather the carbon +dioxid from the atmosphere and the soil; few natural waters are free +from it. The hardest rock particles are disintegrated by carbonated +water, while limestones, or rocks containing lime, are readily +dissolved. + +The result of the action of carbonated water upon soil particles is +to render soluble, and therefore more available to plants, many of +the important plant-foods. In this way the action of water, holding +in solution carbon dioxid and other substances, tends to make the +soil more fertile. + +The second great chemical agency of soil formation is the oxygen of +the air. Oxidation is a process of more or less rapid burning, which +tends to accelerate the disintegration of rocks. + +Finally, the _plants _growing in soils are powerful agents of soil +formation. First, the roots forcing their way into the soil exert a +strong pressure which helps to pulverize the soil grains; secondly, +the acids of the plant roots actually dissolve the soil, and third, +in the mass of decaying plants, substances are formed, among them +carbon dioxid, that have the power of making soils more soluble. + +It may be noted that moisture, carbon dioxid, and vegetation, the +three chief agents inducing chemical changes in soils, are most +active in humid districts. While, therefore, the physical agencies +of soil formation are most active in arid climates, the same cannot +be said of the chemical agencies. However, whether in arid or humid +climates, the processes of soil formation, above outlined, are +essentially those of the "fallow" or resting-period given to +dry-farm lands. The fallow lasts for a few months or a year, while +the process of soil formation is always going on and has gone on for +ages; the result, in quality though not in quantity, is the +same--the rock particles are pulverized and the plant-foods are +liberated. It must be remembered in this connection that climatic +differences may and usually do influence materially the character of +soils formed from one and the same kind of rock. + +Characteristics of arid soils + +The net result of the processes above described Is a rock powder +containing a great variety of sizes of soil grains intermingled with +clay. The larger soil grains are called sand; the smaller, silt, and +those that are so small that they do not settle from quiet water +after 24 hours are known as clay. + +Clay differs materially from sand and silt, not only in size of +particles, but also in properties and formation. It is said that +clay particles reach a degree of fineness equal to 1/2500 of an +inch. Clay itself, when wet and kneaded, becomes plastic and +adhesive and is thus easily distinguished from sand. Because of +these properties, clay is of great value in holding together the +larger soil grains in relatively large aggregates which give soils +the desired degree of filth. Moreover, clay is very retentive of +water, gases, and soluble plant-foods, which are important factors +in successful agriculture. Soils, in fact, are classified according +to the amount of clay that they contain. Hilgard suggests the +following classification:-- + + +Very sandy soils 0.5 to 3 per cent clay +Ordinary sandy soils 3.0 to 10 per cent clay +Sandy loams 10.0 to 15 per cent clay +Clay loams 15.0 to 25 per cent clay +Clay soils 25.0 to 35 per cent clay +Heavy clay soils 35.0 per cent and over + + +Clay may be formed from any rock containing some form of _combined +silica _(quartz). Thus, granites and crystalline rocks generally, +volcanic rocks, and shales will produce clay if subjected to the +proper climatic conditions. In the formation of clay, the extremely +fine soil particles are attacked by the soil water and subjected to +deep-going chemical changes. In fact, clay represents the most +finely pulverized and most highly decomposed and hence in a measure +the most valuable portion of the soil. In the formation of clay, +water is the most active agent, and under humid conditions its +formation is most rapid. + +It follows that dry-farm soils formed under a more or less rainless +climate contain less clay than do humid soils. This difference is +characteristic, and accounts for the statement frequently made that +heavy clay soils are not the best for dry-farm purposes. The fact +is, that heavy clay soils are very rare in arid regions; if found at +all, they have probably been formed under abnormal conditions, as in +high mountain valleys, or under prehistoric humid climates. + +_Sand.--_The sand-forming rocks that are not capable of clay +production usually consist of _uncombined silica _or quartz, which +when pulverized by the soil-forming agencies give a comparatively +barren soil. Thus it has come about that ordinarily a clayey soil is +considered "strong" and a sandy soil "weak." Though this distinction +is true in humid climates where clay formation is rapid, it is not +true in arid climates, where true clay is formed very slowly. Under +conditions of deficient rainfall, soils are naturally less clayey, +but as the sand and silt particles are produced from rocks which +under humid conditions would yield clay, arid soils are not +necessarily less fertile. + +Experiment has shown that the fertility in the sandy soils of arid +sections is as large and as available to plants as in the clayey +soils of humid regions. Experience in the arid section of America, +in Egypt, India, and other desert-like regions has further proved +that the sands of the deserts produce excellent crops whenever water +is applied to them. The prospective dry-farmer, therefore, need not +be afraid of a somewhat sandy soil, provided it has been formed +under arid conditions. In truth, a degree of sandiness is +characteristic of dry-farm soils. + +The _humus _content forms another characteristic difference between +arid and humid soils. In humid regions plants cover the soil +thickly; in arid regions they are bunched scantily over the surface; +in the former case the decayed remnants of generations of plants +form a large percentage of humus in the upper soil; in the latter, +the scarcity of plant life makes the humus content low. Further, +under an abundant rainfall the organic matter in the soil rots +slowly; whereas in dry warm climates the decay is very complete. The +prevailing forces in all countries of deficient rainfall therefore +tend to yield soils low in humus. + +While the total amount of humus in arid soils is very much lower +than in humid soils, repeated investigation has shown that it +contains about 3-1/2 times more nitrogen than is found in humus +formed under an abundant rainfall. Owing to the prevailing sandiness +of dry-farm soils, humus is not needed so much to give the proper +filth to the soil as in the humid countries where the content of +clay is so much higher. Since, for dry-farm purposes, the nitrogen +content is the most important quality of the humus, the difference +between arid and humid soils, based upon the humus content, is not +so great as would appear at first sight. + +_Soil and subsoil.--_In countries of abundant rainfall, a great +distinction exists between the soil and the subsoil. The soil is +represented by the upper few inches which are filled with the +remnants of decayed vegetable matter and modified by plowing, +harrowing, and other cultural operations. The subsoil has been +profoundly modified by the action of the heavy rainfall, which, in +soaking through the soil, has carried with it the finest soil +grains, especially the clay, into the lower soil layers. + +In time, the subsoil has become more distinctly clayey than the +topsoil. Lime and other soil ingredients have likewise been carried +down by the rains and deposited at different depths in the soil or +wholly washed away. Ultimately, this results in the removal from the +topsoil of the necessary plant-foods and the accumulation in the +subsoil of the fine clay particles which so compact the subsoil as +to make it difficult for roots and even air to penetrate it. The +normal process of weathering or soil disintegration will then go on +most actively in the topsoil and the subsoil will remain unweathered +and raw. This accounts for the well-known fact that in humid +countries any subsoil that may have been plowed up is reduced to a +normal state of fertility and crop production only after several +years of exposure to the elements. The humid farmer, knowing this, +is usually very careful not to let his plow enter the subsoil to any +great depth. + +In the arid regions or wherever a deficient rainfall prevails, these +conditions are entirely reversed. The light rainfall seldom +completely fills the soil pores to any considerable depth, but it +rather moves down slowly as a him, enveloping the soil grains. The +soluble materials of the soil are, in part at least, dissolved and +carried down to the lower limit of the rain penetration, but the +clay and other fine soil particles are not moved downward to any +great extent. These conditions leave the soil and subsoil of +approximately equal porosity. Plant roots can then penetrate the +soil deeply, and the air can move up and down through the soil mass +freely and to considerable depths. As a result, arid soils are +weathered and made suitable for plant nutrition to very great +depths. In fact, in dry-farm regions there need be little talk about +soil and subsoil, since the soil is uniform in texture and usually +nearly so in composition, from the top down to a distance of many +feet. + +Many soil sections 50 or more feet in depth are exposed in the +dry-farming territory of the United States, and it has often been +demonstrated that the subsoil to any depth is capable of producing, +without further weathering, excellent yields of crops. This +granular, permeable structure, characteristic of arid soils, is +perhaps the most important single quality resulting from rock +disintegration under arid conditions. As Hilgard remarks, it would +seem that the farmer in the arid region owns from three to four +farms, one above the other, as compared with the same acreage in the +eastern states. + +This condition is of the greatest importance in developing the +principles upon which successful dry-farming rests. Further, it may +be said that while in the humid East the farmer must be extremely +careful not to turn up with his plow too much of the inert subsoil, +no such fear need possess the western farmer. On the contrary, he +should use his utmost endeavor to plow as deeply as possible in +order to prepare the very best reservoir for the falling waters and +a place for the development of plant roots. + +_Gravel seams.--_It need be said, however, that in a number of +localities in the dry-farm territory the soils have been deposited +by the action of running water in such a way that the otherwise +uniform structure of the soil is broken by occasional layers of +loose gravel. While this is not a very serious obstacle to the +downward penetration of roots, it is very serious in dry-farming, +since any break in the continuity of the soil mass prevents the +upward movement of water stored in the lower soil depths. The +dry-farmer should investigate the soil which he intends to use to a +depth of at least 8 to 10 feet to make sure, first of all, that he +has a continuous soil mass, not too clayey in the lower depths, nor +broken by deposits of gravel. + +_Hardpan.--_Instead of the heavy clay subsoil of humid regions, the +so-called hardpan occurs in regions of limited rainfall. The annual +rainfall, which is approximately constant, penetrates from year to +year very nearly to the same depth. Some of the lime found so +abundantly in arid soils is dissolved and worked down yearly to the +lower limit of the rainfall and left there to enter into combination +with other soil ingredients. Continued through long periods of time +this results in the formation of a layer of calcareous material at +the average depth to which the rainfall has penetrated the soil. Not +only is the lime thus carried down, but the finer particles are +carried down in like manner. Especially where the soil is poor in +lime is the clay worked down to form a somewhat clayey hardpan. A +hardpan formed in such a manner is frequently a serious obstacle to +the downward movement of the roots, and also prevents the annual +precipitation from moving down far enough to be beyond the influence +of the sunshine and winds. It is fortunate, however, that in the +great majority of instances this hardpan gradually disappears under +the influence of proper methods of dry-farm tillage. Deep plowing +and proper tillage, which allow the rain waters to penetrate the +soil, gradually break up and destroy the hardpan, even when it is 10 +feet below the surface. Nevertheless, the farmer should make sure +whether or not the hardpan does exist in the soil and plan his +methods accordingly. If a hardpan is present, the land must be +fallowed more carefully every other year, so that a large quantity +of water may be stored in the soil to open and destroy the hardpan. + +Of course, in arid as in humid countries, it often happens that a +soil is underlaid, more or less near the surface, by layers of rock, +marl deposits, and similar impervious or hurtful substances. Such +deposits are not to be classed with the hardpans that occur normally +wherever the rainfall is small. + +_Leaching.--_Fully as important as any of the differences above +outlined are those which depend definitely upon the leaching power +of a heavy rainfall. In countries where the rainfall is 30 inches or +over, and in many places where the rainfall is considerably less, +the water drains through the soil into the standing ground water. +There is, therefore, in humid countries, a continuous drainage +through the soil after every rain, and in general there is a steady +downward movement of soil-water throughout the year. As is clearly +shown by the appearance, taste, and chemical composition of drainage +waters, this process leaches out considerable quantities of the +soluble constituents of the soil. + +When the soil contains decomposing organic matter, such as roots, +leaves, stalks, the gas carbon dioxid is formed, which, when +dissolved in water, forms a solution of great solvent power. Water +passing through well-cultivated soils containing much humus leaches +out very much more material than pure water could do. A study of the +composition of the drainage waters from soils and the waters of the +great rivers shows that immense quantities of soluble soil +constituents are taken out of the soil in countries of abundant +rainfall. These materials ultimately reach the ocean, where they are +and have been concentrated throughout the ages. In short, the +saltiness of the ocean is due to the substances that have been +washed from the soils in countries of abundant rainfall. + +In arid regions, on the other hand, the rainfall penetrates the soil +only a few feet. In time, it is returned to the surface by the +action of plants or sunshine and evaporated into the air. It is true +that under proper methods of tillage even the light rainfall of arid +and semiarid regions may he made to pass to considerable soil +depths, yet there is little if any drainage of water through the +soil into the standing ground water. The arid regions of the world, +therefore, contribute proportionately a small amount of the +substances which make up the salt of the sea. + +_Alkali soils.--_Under favorable conditions it sometimes happens +that the soluble materials, which would normally be washed out of +humid soils, accumulate to so large a degree in arid soils as to +make the lands unfitted for agricultural purposes. Such lands are +called alkali lands. Unwise irrigation in arid climates frequently +produces alkali spots, but many occur naturally. Such soils should +not be chosen for dry-farm purposes, for they are likely to give +trouble. + +_Plant-food content.--_This condition necessarily leads at once to +the suggestion that the soils from the two regions must differ +greatly in their fertility or power to produce and sustain plant +life. It cannot be believed that the water-washed soils of the East +retain as much fertility as the dry soils of the West. Hilgard has +made a long and elaborate study of this somewhat difficult question +and has constructed a table showing the composition of typical soils +of representative states in the arid and humid regions. The +following table shows a few of the average results obtained by +him:-- + + +Partial Percentage Composition + +Source of soil Humid Arid +Number of samples analyzed 696 573 +Insoluble residue 84.17 69.16 +Soluble silica 4.04 6.71 +Alumina 3.66 7.61 +Lime 0.13 1.43 +Potash 0.21 0.67 +Phos. Acid 0.12 0.16 +Humus 1.22 1.13 + + +Soil chemists have generally attempted to arrive at a determination +of the fertility of soil by treating a carefully selected and +prepared sample with a certain amount of acid of definite strength. +The portion which dissolves under the influence of acids has been +looked upon as a rough measure of the possible fertility of the +soil. + +The column headed "Insoluble Residue" shows the average proportions +of arid and humid soils which remain undissolved by acids. It is +evident at once that the humid soils are much less soluble in acids +than arid soils, the difference being 84 to 69. Since the only +plant-food in soils that may be used for plant production is that +which is soluble, it follows that it is safe to assume that arid +soils are generally more fertile than humid soils. This is borne out +by a study of the constituents of the soil. For instance, potash, +one of the essential plant foods ordinarily present in sufficient +amount, is found in humid soils to the extent of 0.21 per cent, +while in arid soils the quantity present is 0.67 per cent, or over +three times as much. Phosphoric acid, another of the very important +plant-foods, is present in arid soils in only slightly higher +quantities than in humid soils. This explains the somewhat +well-known fact that the first fertilizer ordinarily required by +arid soils is some form of phosphorus: + +The difference in the chemical composition of arid and humid soils +is perhaps shown nowhere better than in the lime content. There is +nearly eleven times more lime in arid than in humid soils. +Conditions of aridity favor strongly the formation of lime, and +since there is very little leaching of the soil by rainfall, the +lime accumulates in the soil. + +The presence of large quantities of lime in arid soils has a number +of distinct advantages, among which the following are most +important: (1) It prevents the sour condition frequently present in +humid climates, where much organic material is incorporated with the +soil. (2) When other conditions are favorable, it encourages +bacterial life which, as is now a well-known fact, is an important +factor in developing and maintaining soil fertility. (3) By somewhat +subtle chemical changes it makes the relatively small percentages of +other plant-foods notably phosphoric acid and potash, more available +for plant growth. (4) It aids to convert rapidly organic matter into +humus which represents the main portion of the nitrogen content of +the soil. + +Of course, an excess of lime in the soil may be hurtful, though less +so in arid than in humid regions. Some authors state that from 8 to +20 per cent of calcium carbonate makes a soil unfitted for plant +growth. There are, however, a great many agricultural soils covering +large areas and yielding very abundant crops which contain very much +larger quantities of calcium carbonate. For instance, in the Sanpete +Valley of Utah, one of the most fertile sections of the Great Basin, +agricultural soils often contain as high as 40 per cent of calcium +carbonate, without injury to their crop-producing power. + +In the table are two columns headed "Soluble Silica" and "Alumina," +in both of which it is evident that a very much larger per cent is +found in the arid than in the humid soils. These soil constituents +indicate the condition of the soil with reference to the +availability of its fertility for plant use. The higher the +percentage of soluble silica and alumina, the more thoroughly +decomposed, in all probability, is the soil as a whole and the more +readily can plants secure their nutriment from the soil. It will be +observed from the table, as previously stated, that more humus is +found in humid than in arid soils, though the difference is not so +large as might be expected. It should be recalled, however, that the +nitrogen content of humus formed under rainless conditions is many +times larger than that of humus formed in rainy countries, and that +the smaller per cent of humus in dry-farming countries is thereby +offset. + +All in all, the composition of arid soils is very much more +favorable to plant growth than that of humid soils. As will be shown +in Chapter IX, the greater fertility of arid soils is one of the +chief reasons for dry-farming success. Depth of the soil alone does +not suffice. There must be a large amount of high fertility +available for plants in order that the small amount of water can be +fully utilized in plant growth. + +_Summary of characteristics.--_Arid soils differ from humid soils in +that they contain: less clay; more sand, but of fertile nature +because it is derived from rocks that in humid countries would +produce clay; less humus, but that of a kind which contains about +3-1/2 times more nitrogen than the humus of humid soils; more lime, +which helps in a variety of ways to improve the agricultural value +of soils; more of all the essential plant-foods, because the +leaching by downward drainage is very small in countries of limited +rainfall. + +Further, arid soils show no real difference between soil and +subsoil; they are deeper and more permeable; they are more uniform +in structure; they have hardpans instead of clay subsoil, which, +however, disappear under the influence of cultivation; their +subsoils to a depth of ten feet or more are as fertile as the +topsoil, and the availability of the fertility is greater. The +failure to recognize these characteristic differences between arid +and humid soils has been the chief cause for many crop failures in +the more or less rainless regions of the world. + +This brief review shows that, everything considered, arid soils are +superior to humid soils. In ease of handling, productivity, +certainty of crop-lasting quality, they far surpass the soils of the +countries in which scientific agriculture was founded. As Hilgard +has suggested, the historical datum that the majority of the most +populous and powerful historical peoples of the world have been +located on soils that thirst for water, may find its explanation in +the intrinsic value of arid soils. From Babylon to the United States +is a far cry; but it is one that shouts to the world the superlative +merits of the soil that begs for water. To learn how to use the +"desert" is to make it "blossom like the rose." + +Soil divisions + +The dry-farm territory of the United States may be divided roughly +into five great soil districts, each of which includes a great +variety of soil types, most of which are poorly known and mapped. +These districts are:-- + + +1. Great Plains district. +2. Columbia River district +3. Great Basin district. +4. Colorado River district. +5. California district. + + +_Great Plains district.--_On the eastern slope of the Rocky +Mountains, extending eastward to the extreme boundary of the +dry-farm territory, are the soils of the High Plains and the Great +Plains. This vast soil district belongs to the drainage basin of the +Missouri, and includes North and South Dakota, Nebraska, Kansas, +Oklahoma, and parts of Montana, Wyoming, Colorado, New Mexico, +Texas, and Minnesota. The soils of this district are usually of high +fertility. They have good lasting power, though the effect of the +higher rainfall is evident in their composition. Many of the +distinct types of the plains soils have been determined with +considerable care by Snyder and Lyon, and may be found described in +Bailey's "Cyclopedia of American Agriculture," Vol. I. + +_Columbia River district.--_The second great soil district of the +dry-farming territory is located in the drainage basin of the +Columbia River, and includes Idaho and the eastern two thirds of +Washington and Oregon. The high plains of this soil district are +often spoken of as the Palouse country. The soils of the western +part of this district are of basaltic origin; over the southern part +of Idaho the soils have been made from a somewhat recent lava flow +which in many places is only a few feet below the surface. The soils +of this district are generally of volcanic origin and very much +alike. They are characterized by the properties which normally +belong to volcanic soils; somewhat poor in lime, but rich in potash +and phosphoric acid. They last well under ordinary methods of +tillage. + +_The Great Basin.--_The third great soil district is included in the +Great Basin, which covers nearly all of Nevada, half of Utah, and +takes small portions out of Idaho, Oregon, and southern California. +This basin has no outlet to the sea. Its rivers empty into great +saline inland lakes, the chief of which is the Great Salt Lake. The +sizes of these interior lakes are determined by the amounts of water +flowing into them and the rates of evaporation of the water into the +dry air of the region. + +In recent geological times, the Great Basin was filled with water, +forming a vast fresh-water lake known as Lake Bonneville, which +drained into the Columbia River. During the existence of this lake, +soil materials were washed from the mountains into the lake and +deposited on the lake bottom. When at length, the lake disappeared, +the lake bottom was exposed and is now the farming lands of the +Great Basin district. The soils of this district are characterized +by great depth and uniformity, an abundance of lime, and all the +essential plant-foods with the exception of phosphoric acid, which, +while present in normal quantities, is not unusually abundant. The +Great Basin soils are among the most fertile on the American +Continent. + +_Colorado River district.--_The fourth soil district lies in the +drainage basin of the Colorado River It includes much of the +southern part of Utah, the eastern part of Colorado, part of New +Mexico, nearly all of Arizona, and part of southern California. This +district, in its northern part, is often spoken of as the High +Plateaus. The soils are formed from the easily disintegrated rocks +of comparatively recent geological origin, which themselves are said +to have been formed from deposits in a shallow interior sea which +covered a large part of the West. The rivers running through this +district have cut immense canons with perpendicular walls which make +much of this country difficult to traverse. Some of the soils are of +an extremely fine nature, settling firmly and requiring considerable +tillage before they are brought to a proper condition of tilth. In +many places the soils are heavily charged with calcium sulfate, or +crystals of the ordinary land plaster. The fertility of the soils, +however, is high, and when they are properly cultivated, they yield +large and excellent crops. + +_California district.--_The fifth soil district lies in California +in the basin of the Sacramento and San Joaquin rivers. The soils are +of the typical arid kind of high fertility and great lasting powers. +They represent some of the most valuable dry-farm districts of the +West. These soils have been studied in detail by Hilgard. + +_Dry-farming in the five districts.--_It is interesting to note that +in all of these five great soil districts dry-farming has been tried +with great success. Even in the Great Basin and the Colorado River +districts, where extreme desert conditions often prevail and where +the rainfall is slight, it has been found possible to produce +profitable crops without irrigation. It is unfortunate that the +study of the dry-farming territory of the United States has not +progressed far enough to permit a comprehensive and correct mapping +of its soils. Our knowledge of this subject is, at the best, +fragmentary. We know, however, with certainty that the properties +which characterize arid soils, as described in this chapter' are +possessed by the soils of the dry-farming territory, including the +five great districts just enumerated. The characteristics of arid id +soils increase as the rainfall decreases and other conditions of +aridity increase. They are less marked as we go eastward or westward +toward the regions of more abundant rainfall; that is to say, the +most highly developed arid soils are found in the Great Basin and +Colorado River districts. The least developed are on the eastern +edge of the Great Plains. + +The judging of soils + +A chemical analysis of a soil, unless accompanied by a large amount +of other information, is of little value to the farmer. The main +points in judging a prospective dry-farm are: the depth of the soil, +the uniformity of the soil to a depth of at least 10 feet, the +native vegetation, the climatic conditions as relating to early and +late frosts, the total annual rainfall and its distribution, and the +kinds and yields of crops that have been grown in the neighborhood. + +The depth of the soil is best determined by the use of an auger. A +simple soil auger is made from the ordinary carpenter's auger, 1-1/2 +to 2 inches in diameter, by lengthening its shaft to 3 feet or more. +Where it is not desirable to carry sectional augers, it is often +advisable to have three augers made: one 3 feet, the other 6, and +the third 9 or 10 feet in length. The short auger is used first and +the others afterwards as the depth of the boring increases. The +boring should he made in a large number of average +places--preferably one boring or more on each acre if time and +circumstances permit--and the results entered on a map of the farm. +The uniformity of the soil is observed as the boring progresses. If +gravel layers exist, they will necessarily stop the progress of the +boring. Hardpans of any kind will also be revealed by such an +examination. + +The climatic information must be gathered from the local weather +bureau and from older residents of the section. + +The native vegetation is always an excellent index of dry-farm +possibilities. If a good stand of native grasses exists, there can +scarcely be any doubt about the ultimate success of dry-farming +under proper cultural methods. A healthy crop of sagebrush is an +almost absolutely certain indication that farming without irrigation +is feasible. The rabbit brush of the drier regions is also usually a +good indication, though it frequently indicates a soil not easily +handled. Greasewood, shadscale, and other related plants ordinarily +indicate heavy clay soils frequently charged with alkali. Such soils +should be the last choice for dry-farming purposes, though they +usually give good satisfaction under systems of irrigation. If the +native cedar or other native trees grow in profusion, it is another +indication of good dry-farm possibilities. + + + + + + +CHAPTER VI + +THE ROOT SYSTEMS OF PLANTS + + + + + +The great depth and high fertility of the soils of arid and semiarid +regions have made possible the profitable production of agricultural +plants under a rainfall very much lower than that of humid regions. +To make the principles of this system fully understood, it is +necessary to review briefly our knowledge of the root systems of +plants growing under arid conditions. + +Functions of roots + +The roots serve at least three distinct uses or purposes: First, +they give the plant a foothold in the earth; secondly, they enable +the plant to secure from the soil the large amount of water needed +in plant growth, and, thirdly, they enable the plant to secure the +indispensable mineral foods which can be obtained only from the +soil. So important is the proper supply of water and food in the +growth of a plant that, in a given soil, the crop yield is usually +in direct proportion to the development of the root system. Whenever +the roots are hindered in their development, the growth of the plant +above ground is likewise retarded, and crop failure may result. The +importance of roots is not fully appreciated because they are hidden +from direct view. Successful dry-farming consists, largely in the +adoption of practices that facilitate a full and free development-of +plant roots. Were it not that the nature of arid soils, as explained +in preceding chapters, is such that full root development is +comparatively easy, it would probably be useless to attempt to +establish a system of dry-farming. + +Kinds of roots + +The root is the part of the plant that is found underground. It has +numerous branches, twigs, and filaments. The root which first forms +when the seed bursts is known as the primary root. From this primary +root other roots develop, which are known as secondary roots. When +the primary root grows more rapidly than the secondary roots, the +so-called taproot, characteristic of lucerne, clover, and similar +plants, is formed. When, on the other hand, the taproot grows slowly +or ceases its growth, and the numerous secondary roots grow long, a +fibrous root system results, which is characteristic of the cereals, +grasses, corn, and other similar plants. With any type of root, the +tendency of growth is downward; though under conditions that are not +favorable for the downward penetration of the roots the lateral +extensions may be very large and near the surface + +Extent of roots + +A number of investigators have attempted to determine the weight of +the roots as compared with the weight of the plant above ground, hut +the subject, because of its great experimental difficulties, has not +been very accurately explained. Schumacher, experimenting about +1867, found that the roots of a well-established field of clover +weighed as much as the total weight of the stems and leaves of the +year's crop, and that the weight of roots of an oat crop was 43 per +cent of the total weight of seed and straw. Nobbe, a few years +later, found in one of his experiments that the roots of timothy +weighed 31 per cent of the weight of the hay. Hosaeus, investigating +the same subject about the same time, found that the weight of roots +of one of the brome grasses was as great as the weight of the part +above ground; of serradella, 77 per cent; of flax, 34 per cent; of +oats, 14 per cent; of barley, 13 per cent, and of peas, 9 per cent. +Sanborn, working at the Utah Station in 1893, found results very +much the same + +Although these results are not concordant, they show that the weight +of the roots is considerable, in many cases far beyond the belief of +those who have given the subject little or no attention. It may be +noted that on the basis of the figures above obtained, it is very +probable that the roots in one acre of an average wheat crop would +weigh in the neighborhood of a thousand pounds--possibly +considerably more. It should be remembered that the investigations +which yielded the preceding results were all conducted in humid +climates and at a time when the methods for the study of the root +systems were poorly developed. The data obtained, therefore, +represent, in all probability, minimum results which would be +materially increased should the work be repeated now. + +The relative weights of the roots and the stems and the leaves do +not alone show the large quantity of roots; the total lengths of the +roots are even more striking. The German investigator, Nobbe, in a +laborious experiment conducted about 1867, added the lengths of all +the fine roots from each of various plants. He found that the total +length of roots, that is, the sum of the lengths of all the roots, +of one wheat plant was about 268 feet, and that the total length of +the roots of one plant of rye was about 385 feet. King, of +Wisconsin, estimates that in one of his experiments, one corn plant +produced in the upper 3 feet of soil 1452 feet of roots. These +surprisingly large numbers indicate with emphasis the thoroughness +with which the roots invade the soil. + +Depth of root penetration + +The earlier root studies did not pretend to determine the depth to +which roots actually penetrate the earth. In recent years, however, +a number of carefully conducted experiments were made by the New +York, Wisconsin, Minnesota, Kansas, Colorado, and especially the +North Dakota stations to obtain accurate information concerning the +depth to which agricultural plants penetrate soils. It is somewhat +regrettable, for the purpose of dry-farming, that these states, with +the exception of Colorado, are all in the humid or sub-humid area of +the United States. Nevertheless, the conclusions drawn from the work +are such that they may be safely applied in the development of the +principles of dry-farming. + +There is a general belief among farmers that the roots of all +cultivated crops are very near the surface and that few reach a +greater depth than one or two feet. The first striking result of the +American investigations was that every crop, without exception, +penetrates the soil deeper than was thought possible in earlier +days. For example, it was found that corn roots penetrated fully +four feet into the ground and that they fully occupied all of the +soil to that depth. + +On deeper and somewhat drier soils, corn roots went down as far as +eight feet. The roots of the small grains,--wheat, oats, +barley,--penetrated the soil from four to eight or ten feet. Various +perennial grasses rooted to a depth of four feet the first year; the +next year, five and one half feet; no determinations were made of +the depth of the roots in later years, though it had undoubtedly +increased. Alfalfa was the deepest rooted of all the crops studied +by the American stations. Potato roots filled the soil fully to a +depth of three feet; sugar beets to a depth of nearly four feet. + +Sugar Beet Roots + +In every case, under conditions prevailing in the experiments, and +which did not have in mind the forcing of the roots down to +extraordinary depths, it seemed that the normal depth of the roots +of ordinary field crops was from three to eight feet. Sub-soiling +and deep plowing enable the roots to go deeper into the soil. This +work has been confirmed in ordinary experience until there can be +little question about the accuracy of the results. + +Almost all of these results were obtained in humid climates on humid +soils, somewhat shallow, and underlain by a more or less infertile +subsoil. In fact, they were obtained under conditions really +unfavorable to plant growth. It has been explained in Chapter V that +soils formed under arid or semiarid conditions are uniformly deep +and porous and that the fertility of the subsoil is, in most cases, +practically as great as of the topsoil. There is, therefore, in arid +soils, an excellent opportunity for a comparatively easy penetration +of the roots to great depths and, because of the available +fertility, a chance throughout the whole of the subsoil for ample +root development. Moreover, the porous condition of the soil permits +the entrance of air, which helps to purify the soil atmosphere and +thereby to make the conditions more favorable for root development. +Consequently it is to be expected that, in arid regions, roots will +ordinarily go to a much greater depth than in humid regions. + +It is further to be remembered that roots are in constant search of +food and water and are likely to develop in the directions where +there is the greatest abundance of these materials. Under systems of +dry-farming the soil water is stored more or less uniformly to +considerable depths--ten feet or more--and in most cases the +percentage of moisture in the spring and summer is as large or +larger some feet below the surface than in the upper two feet. The +tendency of the root is, then, to move downward to depths where +there is a larger supply of water. Especially is this tendency +increased by the available soil fertility found throughout the whole +depth of the soil mass. + +It has been argued that in many of the irrigated sections the roots +do not penetrate the soil to great depths. This is true, because by +the present wasteful methods of irrigation the plant receives so +much water at such untimely seasons that the roots acquire the habit +of feeding very near the surface where the water is so lavishly +applied. This means not only that the plant suffers more greatly in +times of drouth, but that, since the feeding ground of the roots is +smaller, the crop is likely to be small. + +These deductions as to the depth to which plant roots will penetrate +the soil in arid regions are fully corroborated by experiments and +general observation. The workers of the Utah Station have repeatedly +observed plant roots on dry-farms to a depth of ten feet. Lucerne +roots from thirty to fifty feet in length are frequently exposed in +the gullies formed by the mountain torrents. Roots of trees, +similarly, go down to great depths. Hilgard observes that he has +found roots of grapevines at a depth of twenty-two feet below the +surface, and quotes Aughey as having found roots of the native +Shepherdia in Nebraska to a depth of fifty feet. Hilgard further +declares that in California fibrous-rooted plants, such as wheat and +barley, may descend in sandy soils from four to seven feet. Orchard +trees in the arid West, grown properly, are similarly observed to +send their roots down to great depths. In fact, it has become a +custom in many arid regions where the soils are easily penetrable to +say that the root system of a tree corresponds in extent and +branching to the part of the tree above ground. + +Now, it is to be observed that, generally, plants grown in dry +climates send their roots straight down into the soil; whereas in +humid climates, where the topsoil is quite moist and the subsoil is +hard, roots branch out laterally and fill the upper foot or two of +the soil. A great deal has been said and written about the danger of +deep cultivation, because it tends to injure the roots that feed +near the surface. However true this may be in humid countries, it is +not vital in the districts primarily interested in dry-farming; and +it is doubtful if the objection is as valid in humid countries as is +often declared. True, deep cultivation, especially when performed +near the plant or tree, destroys the surface-feeding roots, but this +only tends to compel the deeper lying roots to make better use of +the subsoil. + +When, as in arid regions, the subsoil is fertile and furnishes a +sufficient amount of water, destroying the surface roots is no +handicap whatever. On the contrary, in times of drouth, the +deep-lying roots feed and drink at their leisure far from the hot +sun or withering winds, and the plants survive and arrive at rich +maturity, while the plants with shallow roots wither and die or are +so seriously injured as to produce an inferior crop. Therefore, in +the system of dry-farming as developed in this volume, it must be +understood that so far as the farmer has power, the roots must be +driven downward into the soil, and that no injury needs to be +apprehended from deep and vigorous cultivation. + +One of the chief attempts of the dry-farmer must be to see to it +that the plants root deeply. This can be done only by preparing the +right kind of seed-bed and by having the soil in its lower depths +well-stored with moisture, so that the plants may be invited to +descend. For that reason, an excess of moisture in the upper soil +when the young plants are rooting is really an injury to them. + + + + + + +CHAPTER VII + +STORING WATER IN THE SOIL + + + + + +The large amount of water required for the production of plant +substance is taken from the soil by the roots. Leaves and stems do +not absorb appreciable quantities of water. The scanty rainfall of +dry-farm districts or the more abundant precipitation of humid +regions must, therefore, be made to enter the soil in such a manner +as to be readily available as soil-moisture to the roots at the +right periods of plant growth. + +In humid countries, the rain that falls during the growing season is +looked upon, and very properly, as the really effective factor in +the production of large crops. The root systems of plants grown +under such humid conditions are near the surface, ready to absorb +immediately the rains that fall, even if they do not soak deeply +into the soil. As has been shown in Chapter IV, it is only over a +small portion of the dry-farm territory that the bulk of the scanty +precipitation occurs during the growing season. Over a large portion +of the arid and semiarid region the summers are almost rainless and +the bulk of the precipitation comes in the winter, late fall, or +early spring when plants are not growing. If the rains that fall +during the growing season are indispensable in crop production, the +possible area to be reclaimed by dry-farming will be greatly +limited. Even when much of the total precipitation comes in summer, +the amount in dry-farm districts is seldom sufficient for the proper +maturing of crops. In fact, successful dry-farming depends chiefly +upon the success with which the rains that fall during any season of +the year may be stored and kept in the soil until needed by plants +in their growth. The fundamental operations of dry-farming include a +soil treatment which enables the largest possible proportion of the +annual precipitation to be stored in the soil. For this purpose, the +deep, somewhat porous soils, characteristic of arid regions, are +unusually well adapted. + +Alway's demonstration + +An important and unique demonstration of the possibility of bringing +crops to maturity on the moisture stored in the soil at the time of +planting has been made by Alway. Cylinders of galvanized iron, 6 +feet long, were filled with soil as nearly as possible in its +natural position and condition Water was added until seepage began, +after which the excess was allowed to drain away. When the seepage +had closed, the cylinders were entirely closed except at the +surface. Sprouted grains of spring wheat were placed in the moist +surface soil, and 1 inch of dry soil added to the surface to prevent +evaporation. No more water was added; the air of the greenhouse was +kept as dry as possible. The wheat developed normally. The first ear +was ripe in 132 days after planting and the last in 143 days. The +three cylinders of soil from semiarid western Nebraska produced 37.8 +grams of straw and 29 ears, containing 415 kernels weighing 11.188 +grams. The three cylinders of soil from humid eastern Nebraska +produced only 11.2 grams of straw and 13 ears containing 114 +kernels, weighing 3 grams. This experiment shows conclusively that +rains are not needed during the growing season, if the soil is well +filled with moisture at seedtime, to bring crops to maturity. + +What becomes of the rainfall? + +The water that falls on the land is disposed of in three ways: +First, under ordinary conditions, a large portion runs off without +entering the soil; secondly, a portion enters the soil, but remains +near the surface, and is rapidly evaporated back into the air; and, +thirdly, a portion enters the lower soil layers, from which it is +removed at later periods by several distinct processes. The run-off +is usually large and is a serious loss, especially in dry-farming +regions, where the absence of luxuriant vegetation, the somewhat +hard, sun-baked soils, and the numerous drainage channels, formed by +successive torrents, combine to furnish the rains with an easy +escape into the torrential rivers. Persons familiar with arid +conditions know how quickly the narrow box canyons, which often +drain thousands of square miles, are filled with roaring water after +a comparatively light rainfall. + +The run-off + +The proper cultivation of the soil diminishes very greatly the loss +due to run-off, but even on such soils the proportion may often be +very great. Farrel observed at one of the Utah stations that during +a torrential rain--2.6 inches in 4 hours--the surface of the summer +fallowed plats was packed so solid that only one fourth inch, or +less than one tenth of the whole amount, soaked into the soil, while +on a neighboring stubble field, which offered greater hindrance to +the run-off, 1-1/2 inches or about 60 per cent were absorbed. + +It is not possible under any condition to prevent the run-off +altogether, although it can usually be reduced exceedingly. It is a +common dry-farm custom to plow along the slopes of the farm instead +of plowing up and down them. When this is done, the water which runs +down the slopes is caught by the succession of furrows and in that +way the runoff is diminished. During the fallow season the disk and +smoothing harrows are run along the hillsides for the same purpose +and with results that are nearly always advantageous to the +dry-farmer. Of necessity, each man must study his own farm in order +to devise methods that will prevent the run-off. + +The structure of soils + +Before examining more closely the possibility of storing water in +soils a brief review of the structure of soils is desirable. As +previously explained, soil is essentially a mixture of disintegrated +rock and the decomposing remains of plants. The rock particles which +constitute the major portion of soils vary greatly in size. The +largest ones are often 500 times the sizes of the smallest. It would +take 50 of the coarsest sand particles, and 25,000 of the finest +silt particles, to form one lineal inch. The clay particles are +often smaller and of such a nature that they cannot be accurately +measured. The total number of soil particles in even a small +quantity of cultivated soil is far beyond the ordinary limits of +thought, ranging from 125,000 particles of coarse sand to +15,625,000,000,000 particles of the finest silt in one cubic inch. +In other words, if all the particles in one cubic inch of soil +consisting of fine silt were placed side by side, they would form a +continuous chain over a thousand miles long. The farmer, when he +tills the soil, deals with countless numbers of individual soil +grains, far surpassing the understanding of the human mind. It is +the immense number of constituent soil particles that gives to the +soil many of its most valuable properties. + +It must be remembered that no natural soil is made up of particles +all of which are of the same size; all sizes, from the coarsest sand +to the finest clay, are usually present. These particles of all +sizes are not arranged in the soil in a regular, orderly way; they +are not placed side by side with geometrical regularity; they are +rather jumbled together in every possible way. The larger sand +grains touch and form comparatively large interstitial spaces into +which the finer silt and clay grains filter. Then, again, the clay +particles, which have cementing properties, bind, as it were, one +particle to another. A sand grain may have attached to it hundreds, +or it may be thousands, of the smaller silt grains; or a regiment of +smaller soil grains may themselves be clustered into one large grain +by cementing power of the clay. Further, in the presence of lime and +similar substances, these complex soil grains are grouped into yet +larger and more complex groups. The beneficial effect of lime is +usually due to this power of grouping untold numbers of soil +particles into larger groups. When by correct soil culture the +individual soil grains are thus grouped into large clusters, the +soil is said to be in good tilth. Anything that tends to destroy +these complex soil grains, as, for instance, plowing the soil when +it is too wet, weakens the crop-producing power of the soil. This +complexity of structure is one of the chief reasons for the +difficulty of understanding clearly the physical laws governing +soils. + +Pore-space of soils + +It follows from this description of soil structure that the soil +grains do not fill the whole of the soil space. The tendency is +rather to form clusters of soil grains which, though touching at +many points, leave comparatively large empty spaces. This pore space +in soils varies greatly, but with a maximum of about 55 per cent. In +soils formed under arid conditions the percentage of pore-space is +somewhere in the neighborhood of 50 per cent. There are some arid +soils, notably gypsum soils, the particles of which are so uniform +size that the pore-space is exceedingly small. Such soils are always +difficult to prepare for agricultural purposes. + +It is the pore-space in soils that permits the storage of +soil-moisture; and it is always important for the farmer so to +maintain his soil that the pore-space is large enough to give him +the best results, not only for the storage of moisture, but for the +growth and development of roots, and for the entrance into the soil +of air, germ life, and other forces that aid in making the soil fit +for the habitation of plants. This can always be best accomplished, +as will be shown hereafter, by deep plowing, when the soil is not +too wet, the exposure of the plowed soil to the elements, the +frequent cultivation of the soil through the growing season, and the +admixture of organic matter. The natural soil structure at depths +not reached by the plow evidently cannot be vitally changed by the +farmer. + +Hygroscopic soil-water + +Under normal conditions, a certain amount of water is always found +in all things occurring naturally, soils included. Clinging to every +tree, stone, or animal tissue is a small quantity of moisture +varying with the temperature, the amount of water in the air, and +with other well-known factors. It is impossible to rid any natural +substance wholly of water without heating it to a high temperature. +This water which, apparently, belongs to all natural objects is +commonly called hygroscopic water. Hilgard states that the soils of +the arid regions contain, under a temperature of 15 deg C. and an +atmosphere saturated with water, approximately 5-1/2 per cent of +hygroscopic water. In fact, however, the air over the arid region is +far from being saturated with water and the temperature is even +higher than 15 deg C., and the hygroscopic moisture actually found +in the soils of the dry-farm territory is considerably smaller than +the average above given. Under the conditions prevailing in the +Great Basin the hygroscopic water of soils varies from .75 per cent +to 3-1/2 per cent; the average amount is not far from 12 per cent. + +Whether or not the hygroscopic water of soils is of value in plant +growth is a disputed question. Hilgard believes that the hygroscopic +moisture can be of considerable help in carrying plants through +rainless summers, and further, that its presence prevents the +heating of the soil particles to a point dangerous to plant roots. +Other authorities maintain earnestly that the hygroscopic soil-water +is practically useless to plants. Considering the fact that wilting +occurs long before the hygroscopic water contained in the soil is +reached, it is very unlikely that water so held is of any real +benefit to plant growth. + +Gravitational water + +It often happens that a portion of the water in the soil is under +the immediate influence of gravitation. For instance, a stone which, +normally, is covered with hygroscopic water is dipped into water The +hydroscopic water is not thereby affected, but as the stone is drawn +out of the water a good part of the water runs off. This is +gravitational water That is, the gravitational water of soils is +that portion of the soil-water which filling the soil pores, flows +downward through the soil under the influence of gravity. When the +soil pores are completely filled, the maximum amount of +gravitational water is found there. In ordinary dry-farm soils this +total water capacity is between 35 and 40 per cent of the dry weight +of soil. + +The gravitational soil-water cannot long remain in that condition; +for, necessarily, the pull of gravity moves it downward through the +soil pores and if conditions are favorable, it finally reaches the +standing water-table, whence it is carried to the great rivers, and +finally to the ocean. In humid soils, under a large precipitation, +gravitational water moves down to the standing water-table after +every rain. In dry-farm soils the gravitational water seldom reaches +the standing water-table; for, as it moves downward, it wets the +soil grains and remains in the capillary condition as a thin film +around the soil grains. + +To the dry-farmer, the full water capacity is of importance only as +it pertains to the upper foot of soil. If, by proper plowing and +cultivation, the upper soil be loose and porous, the precipitation +is allowed to soak quickly into the soil, away from the action of +the wind and sun. From this temporary reservoir, the water, in +obedience to the pull of gravity, will move slowly downward to the +greater soil depths, where it will be stored permanently until +needed by plants. It is for this reason that dry-farmers find it +profitable to plow in the fall, as soon as possible after +harvesting. In fact, Campbell advocates that the harvester be +followed immediately by the disk, later to be followed by the plow +The essential thing is to keep the topsoil open and receptive to a +rain. + +Capillary soil-water + +The so-called capillary soil-water is of greatest importance to the +dry-farmer. This is the water that clings as a film around a marble +that has been dipped into water. There is a natural attraction +between water and nearly all known substances, as is witnessed by +the fact that nearly all things may be moistened. The water is held +around the marble because the attraction between the marble and the +water is greater than the pull of gravity upon the water. The +greater the attraction, the thicker the film; the smaller the +attraction, the thinner the film will be. The water that rises in a +capillary glass tube when placed in water does so by virtue of the +attraction between water and glass. Frequently, the force that makes +capillary water possible is called surface tension. + +Whenever there is a sufficient amount of water available, a thin +film of water is found around every soil grain; and where the soil +grains touch, or where they are very near together, water is held +pretty much as in capillary tubes. Not only are the soil particles +enveloped by such a film, but the plant roots foraging in the soil +are likewise covered; that is, the whole system of soil grains and +roots is covered, under favorable conditions, with a thin film of +capillary water. It is the water in this form upon which plants draw +during their periods of growth. The hygroscopic water and the +gravitational water are of comparatively little value in plant +growth. + +Field capacity of soils for capillary water + +The tremendously large number of soil grains found in even a small +amount of soil makes it possible for the soil to hold very large +quantities of capillary water. To illustrate: In one cubic inch of +sand soil the total surface exposed by the soil grains varies from +42 square inches to 27 square feet; in one cubic inch of silt soil, +from 27 square feet to 72 square feet, and in one cubic inch of an +ordinary soil the total surface exposed by the soil grains is about +25 square feet. This means that the total surface of the soil grains +contained in a column of soil 1 square foot at the top and 10 feet +deep is approximately 10 acres. When even a thin film of water is +spread over such a large area, it is clear that the total amount of +water involved must be large It is to be noticed, therefore, that +the fineness of the soil particles previously discussed has a direct +bearing upon the amount of water that soils may retain for the use +of plant growth. As the fineness of the soil grains increases, the +total surface increases' and the water-holding capacity also +increases. + +Naturally, the thickness of a water film held around the soil grains +is very minute. King has calculated that a film 275 millionths of an +inch thick, clinging around the soil particles, is equivalent to +14.24 per cent of water in a heavy clay; 7.2 per cent in a loam; +5.21 per cent in a sandy loam, and 1.41 per cent in a sandy soil. + +It is important to know the largest amount of water that soils can +hold in a capillary condition, for upon it depend, in a measure, the +possibilities of crop production under dry-farming conditions. King +states that the largest amount of capillary water that can be held +in sandy loams varies from 17.65 per cent to 10.67 per cent; in clay +loams from 22.67 per cent to 18.16 per cent, and in humus soils +(which are practically unknown in dry-farm sections) from 44.72 per +cent to 21.29 per cent. These results were not obtained under +dry-farm conditions and must be confirmed by investigations of arid +soils. + +The water that falls upon dry-farms is very seldom sufficient in +quantity to reach the standing water-table, and it is necessary, +therefore, to determine the largest percentage of water that a soil +can hold under the influence of gravity down to a depth of 8 or 10 +feet--the depth to which the roots penetrate and in which root +action is distinctly felt. This is somewhat difficult to determine +because the many conflicting factors acting upon the soil-water are +seldom in equilibrium. Moreover, a considerable time must usually +elapse before the rain-water is thoroughly distributed throughout +the soil. For instance, in sandy soils, the downward descent of +water is very rapid; in clay soils, where the preponderance of fine +particles makes minute soil pores, there is considerable hindrance +to the descent of water, and it may take weeks or months for +equilibrium to be established. It is believed that in a dry-farm +district, where the major part of the precipitation comes during +winter, the early springtime, before the spring rains come, is the +best time for determining the maximum water capacity of a soil. At +that season the water-dissipating influences, such as sunshine and +high temperature, are at a minimum, and a sufficient time has +elapsed to permit the rains of fall and winter to distribute +themselves uniformly throughout the soil. In districts of high +summer precipitation, the late fall after a fallow season will +probably be the best time for the determination of the field-water +capacity. + +Experiments on this subject have been conducted at the Utah Station. +As a result of several thousand trials it was found that, in the +spring, a uniform, sandy loam soil of true arid properties +contained, from year to year, an average of nearly 16-1/2 per cent +of water to a depth of 8 feet. This appeared to be practically the +maximum water capacity of that soil under field conditions, and it +may be called the field capacity of that soil for capillary water. +Other experiments on dry-farms showed the field capacity of a clay +soil to a depth of 8 feet to be 19 per cent; of a clay loam, to be +18 per cent; of a loam, 17 per cent; of another loam somewhat more +sandy, 16 per cent; of a sandy loam, 14-1/2 per cent; and of a very +sandy loam, 14 per cent. Leather found that in the calcareous arid +soil of India the upper 5 feet contained 18 per cent of water at the +close of the wet season. + +It may be concluded, therefore, that the field-water capacities of +ordinary dry-farm soils are not very high, ranging from 15 to 20 per +cent, with an average for ordinary dry-farm soils in the +neighborhood of 16 or 17 per cent. Expressed in another way this +means that a layer of water from 2 to 3 inches deep can be stored in +the soil to a depth of 12 inches. Sandy soils will hold less water +than clayey ones. It must not be forgotten that in the dry-farm +region are numerous types of soils, among them some consisting +chiefly of very fine soil grains and which would; consequently, +possess field-water capacities above the average here stated. The +first endeavor of the dry-farmer should be to have the soil filled +to its full field-water capacity before a crop is planted. + +Downward movement of soil-moisture + +One of the chief considerations in a discussion of the storing of +water in soils is the depth to which water may move under ordinary +dry-farm conditions. In humid regions, where the water table is near +the surface and where the rainfall is very abundant, no question has +been raised concerning the possibility of the descent of water +through the soil to the standing water. Considerable objection, +however, has been offered to the doctrine that the rainfall of arid +districts penetrates the soil to any great extent. Numerous writers +on the subject intimate that the rainfall under dry-farm conditions +reaches at the best the upper 3 or 4 feet of soil. This cannot be +true, for the deep rich soils of the arid region, which never have +been disturbed by the husbandman, are moist to very great depths. In +the deserts of the Great Basin, where vegetation is very scanty, +soil borings made almost anywhere will reveal the fact that moisture +exists in considerable quantities to the full depth of the ordinary +soil auger, usually 10 feet. The same is true for practically every +district of the arid region. + +Such water has not come from below, for in the majority of cases the +standing water is 50 to 500 feet below the surface. Whitney made +this observation many years ago and reported it as a striking +feature of agriculture in arid regions, worthy of serious +consideration. Investigations made at the Utah Station have shown +that undisturbed soils within the Great Basin frequently contain, to +a depth of 10 feet, an amount of water equivalent to 2 or 3 years of +the rainfall which normally occurs in that locality. These +quantities of water could not be found in such soils, unless, under +arid conditions, water has the power to move downward to +considerably greater depths than is usually believed by dry-farmers. + +In a series of irrigation experiments conducted at the Utah Station +it was demonstrated that on a loam soil, within a few hours after an +irrigation, some of the water applied had reached the eighth foot, +or at least had increased the percentage of water in the eighth +foot. In soil that was already well filled with water, the addition +of water was felt distinctly to the full depth of 8 feet. Moreover, +it was observed in these experiments that even very small rains +caused moisture changes to considerable depths a few hours after the +rain was over. For instance, 0.14 of an inch of rainfall was felt to +a depth of 2 feet within 3 hours; 0.93 of an inch was felt to a +depth of 3 feet within the same period. + +To determine whether or not the natural winter precipitation, upon +which the crops of a large portion of the dry-farm territory depend, +penetrates the soil to any great depth a series of tests were +undertaken. At the close of the harvest in August or September the +soil was carefully sampled to a depth of 8 feet, and in the +following spring similar samples were taken on the same soils to the +same depth. In every case, it was found that the winter +precipitation had caused moisture changes to the full depth reached +by the soil auger. Moreover, these changes were so great as to lead +the investigators to believe that moisture changes had occurred to +greater depths. + +In districts where the major part of the precipitation occurs during +the summer the same law is undoubtedly in operation; but, since +evaporation is most active in the summer, it is probable that a +smaller proportion reaches the greater soil depths. In the Great +Plains district, therefore, greater care will have to be exercised +during the summer in securing proper water storage than in the Great +Basin, for instance. The principle is, nevertheless, the same. Burr, +working under Great Plains conditions in Nebraska, has shown that +the spring and summer rains penetrate the soil to the depth of 6 +feet, the average depth of the borings, and that it undoubtedly +affects the soil-moisture to the depth of 10 feet. In general, the +dry-farmer may safely accept the doctrine that the water that falls +upon his land penetrates the soil far beyond the immediate reach of +the sun, though not so far away that plant roots cannot make use of +it. + +Importance of a moist subsoil + +In the consideration of the downward movement of soil-water it is to +be noted that it is only when the soil is tolerably moist that the +natural precipitation moves rapidly and freely to the deeper soil +layers. When the soil is dry, the downward movement of the water is +much slower and the bulk of the water is then stored near the +surface where the loss of moisture goes on most rapidly. It has been +observed repeatedly in the investigations at the Utah Station that +when desert land is broken for dry-farm purposes and then properly +cultivated, the precipitation penetrates farther and farther into +the soil with every year of cultivation. For example, on a dry-farm, +the soil of which is clay loam, and which was plowed in the fall of +1904 and farmed annually thereafter, the eighth foot contained in +the spring of 1905, 6.59 per cent of moisture; in the spring of +1906, 13.11 per cent, and in the spring of 1907, 14.75 per cent of +moisture. On another farm, with a very sandy soil and also plowed in +the fall of 1904, there was found in the eighth foot in the spring +of 1905, 5.63 per cent of moisture, in the spring of 1906, 11.41 per +cent of moisture, and in the spring of 1907, 15.49 per cent of +moisture. In both of these typical cases it is evident that as the +topsoil was loosened, the full field water capacity of the soil was +more nearly approached to a greater depth. It would seem that, as +the lower soil layers are moistened, the water is enabled, so to +speak, to slide down more easily into the depths of the soil. + +This is a very important principle for the dry farmer to understand. +It is always dangerous to permit the soil of a dry-farm to become +very dry, especially below the first foot. Dry-farms should be so +manipulated that even at the harvesting season a comparatively large +quantity of water remains in the soil to a depth of 8 feet or more. +The larger the quantity of water in the soil in the fall, the more +readily and quickly will the water that falls on the land during the +resting period of fall, winter, and early spring sink into the soil +and move away from the topsoil. The top or first foot will always +contain the largest percentage of water because it is the chief +receptacle of the water that falls as rain or snow but when the +subsoil is properly moist, the water will more completely leave the +topsoil. Further, crops planted on a soil saturated with water to a +depth of 8 feet are almost certain to mature and yield well. + +If the field-water capacity has not been filled, there is always the +danger that an unusually dry season or a series of hot winds or +other like circumstances may either seriously injure the crop or +cause a complete failure. The dry-farmer should keep a surplus of +moisture in the soil to be carried over from year to year, just as +the wise business man maintains a sufficient working capital for the +needs of his business. In fact, it is often safe to advise the +prospective dry-farmer to plow his newly cleared or broken land +carefully and then to grow no crop on it the first year, so that, +when crop production begins, the soil will have stored in it an +amount of water sufficient to carry a crop over periods of drouth. +Especially in districts of very low rainfall is this practice to be +recommended. In the Great Plains area, where the summer rains tempt +the farmer to give less attention to the soil-moisture problem than +in the dry districts with winter precipitation farther West, it is +important that a fallow season be occasionally given the land to +prevent the store of soil moisture from becoming dangerously low. + +To what extent is the rainfall stored in soils? + +What proportion of the actual amount of water falling upon the soil +can be stored in the soil and carried over from season to season? +This question naturally arises in view of the conclusion that water +penetrates the soil to considerable depths. There is comparatively +little available information with which to answer this question, +because the great majority of students of soil moisture have +concerned themselves wholly with the upper two, three, or four feet +of soil. The results of such investigations are practically useless +in answering this question. In humid regions it may be very +satisfactory to confine soil-moisture investigations to the upper +few feet; but in arid regions, where dry-farming is a living +question, such a method leads to erroneous or incomplete +conclusions. + +Since the average field capacity of soils for water is about 2.5 +inches per foot, it follows that it is possible to store 25 inches +of water in 10 feet of soil. This is from two to one and a half +times one year's rainfall over the better dry-farming sections. +Theoretically, therefore, there is no reason why the rainfall of one +season or more could not be stored in the soil. Careful +investigations have borne out this theory. Atkinson found, for +example, at the Montana Station, that soil, which to a depth of 9 +feet contained 7.7 per cent of moisture in the fall contained 11.5 +per cent in the spring and, after carrying it through the summer by +proper methods of cultivation, 11 per cent. + +It may certainly be concluded from this experiment that it is +possible to carry over the soil moisture from season to season. The +elaborate investigations at the Utah Station have demonstrated that +the winter precipitation, that is, the precipitation that comes +during the wettest period of the year, may be retained in a large +measure in the soil. Naturally, the amount of the natural +precipitation accounted for in the upper eight feet will depend upon +the dryness of the soil at the time the investigation commenced. If +at the beginning of the wet season the upper eight feet of soil are +fairly well stored with moisture, the precipitation will move down +to even greater depths, beyond the reach of the soil auger. If, on +the other hand, the soil is comparatively dry at the beginning of +the season, the natural precipitation will distribute itself through +the upper few feet, and thus be readily measured by the soil auger. + +In the Utah investigations it was found that of the water which fell +as rain and snow during the winter, as high as 95-1/2 per cent was +found stored in the first eight feet of soil at the beginning of the +growing season. Naturally, much smaller percentages were also found, +but on an average, in soils somewhat dry at the beginning of the dry +season, more than three fourths of the natural precipitation was +found stored in the soil in the spring. The results were all +obtained in a locality where the bulk of the precipitation comes in +the winter, yet similar results would undoubtedly be obtained where +the precipitation occurs mainly in the summer. The storage of water +in the soil cannot be a whit less important on the Great Plains than +in the Great Basin. In fact, Burr has clearly demonstrated for +western Nebraska that over 50 per cent of the rainfall of the spring +and summer may be stored in the soil to the depth of six feet. +Without question, some is stored also at greater depths. + +All the evidence at hand shows that a large portion of the +precipitation falling upon properly prepared soil, whether it be +summer or winter, is stored in the soil until evaporation is allowed +to withdraw it Whether or not water so stored may be made to remain +in the soil throughout the season or the year will be discussed in +the next chapter. It must be said, however, that the possibility of +storing water in the soil, that is, making the water descend to +relatively great soil depths away from the immediate and direct +action of the sunshine and winds, is the most fundamental principle +in successful dry-farming. + +The fallow + +It may be safely concluded that a large portion of the water that +falls as rain or snow may be stored in the soil to considerable +depths (eight feet or more). However, the question remains, Is it +possible to store the rainfall of successive years in the soil for +the use of one crop? In short, Does the practice of clean fallowing +or resting the ground with proper cultivation for one season enable +the farmer to store in the soil the larger portion of the rainfall +of two years, to be used for one crop? It is unquestionably true, as +will be shown later, that clean fallowing or "summer tillage" is one +of the oldest and safest practices of dry-farming as practiced in +the West, but it is not generally understood why fallowing is +desirable. + +Considerable doubt has recently been cast upon the doctrine that one +of the beneficial effects of fallowing in dry-farming is to store +the rainfall of successive seasons in the soil for the use of one +crop. Since it has been shown that a large proportion of the winter +precipitation can be stored in the soil during the wet season, it +merely becomes a question of the possibility of preventing the +evaporation of this water during the drier season. As will be shown +in the next chapter, this can well be effected by proper +cultivation. + +There is no good reason, therefore, for believing that the +precipitation of successive seasons may not be added to water +already stored in the soil. King has shown that fallowing the soil +one year carried over per square foot, in the upper four feet, 9.38 +pounds of water more than was found in a cropped soil in a parallel +experiment; and, moreover, the beneficial effect of this. water +advantage was felt for a whole succeeding season. King concludes, +therefore, that one of the advantages of fallowing is to increase +the moisture content of the soil. The Utah experiments show that the +tendency of fallowing is always to increase the soil-moisture +content. In dry-farming, water is the critical factor, and any +practice that helps to conserve water should be adopted. For that +reason, fallowing, which gathers soil-moisture, should be strongly +advocated. In Chapter IX another important value of the fallow will +be discussed. + +In view of the discussion in this chapter it is easily understood +why students of soil-moisture have not found a material increase in +soil-moisture due to fallowing. Usually such investigations have +been made to shallow depths which already were fairly well filled +with moisture. Water falling upon such soils would sink beyond the +depth reached by the soil augers, and it became impossible to judge +accurately of the moisture-storing advantage of the fallow. A +critical analysis of the literature on this subject will reveal the +weakness of most experiments in this respect. + +It may be mentioned here that the only fallow that should be +practiced by the dry-farmer is the clean fallow. Water storage is +manifestly impossible when crops are growing upon a soil. A healthy +crop of sagebrush, sunflowers, or other weeds consumes as much water +as a first-class stand of corn, wheat, or potatoes. Weeds should be +abhorred by the farmer. A weedy fallow is a sure forerunner of a +crop failure. How to maintain a good fallow is discussed in Chapter +VIII, under the head of Cultivation. Moreover, the practice of +fallowing should be varied with the climatic conditions. In +districts of low rainfall, 10-15 inches, the land should be clean +summer-fallowed every other year; under very low rainfall perhaps +even two out of three years; in districts of more abundant rainfall, +15-20 inches, perhaps one year out of every three or four is +sufficient. Where the precipitation comes during the growing season, +as in the Great Plains area, fallowing for the storage of water is +less important than where the major part of the rainfall comes +during the fall and winter. However, any system of dry-farming that +omits fallowing wholly from its practices is in danger of failure in +dry years. + +Deep plowing for water storage + +It has been attempted in this chapter to demonstrate that water +falling upon a soil may descend to great depths, and may be stored +in the soil from year to year, subject to the needs of the crop that +may be planted. By what cultural treatment may this downward descent +of the water be accelerated by the farmer? First and foremost, by +plowing at the right time and to the right depth. Plowing should be +done deeply and thoroughly so that the falling water may immediately +be drawn down to the full depth of the loose, spongy, plowed soil, +away from the action of the sunshine or winds. The moisture thus +caught will slowly work its way down into the lower layers of the +soil. Deep plowing is always to be recommended for successful +dry-farming. + +In humid districts where there is a great difference between the +soil and the subsoil, it is often dangerous to turn up the lifeless +subsoil, but in arid districts where there is no real +differentiation between the soil and the subsoil, deep plowing may +safely be recommended. True, occasionally, soils are found in the +dry-farm territory which are underlaid near the surface by an inert +clay or infertile layer of lime or gypsum which forbids the farmer +putting the plow too deeply into the soil. Such soils, however' are +seldom worth while trying for dry-farm purposes. Deep plowing must +be practiced for the best dry-farming results. + +It naturally follows that subsoiling should be a beneficial practice +on dry-farms. Whether or not the great cost of subsoiling is offset +by the resulting increased yields is an open question; it is, in +fact, quite doubtful. Deep plowing done at the right time and +frequently enough is possibly sufficient. By deep plowing is meant +stirring or turning the soil to a depth of six to ten inches below +the surface of the land. + +Fall plowing far water storage + +It is not alone sufficient to plow and to plow deeply; it is also +necessary that the plowing be done at the right time. In the very +great majority of cases over the whole dry-farm territory, plowing +should be done in the fall. There are three reasons for this: First, +after the crop is harvested, the soil should be stirred immediately, +so that it can be exposed to the full action of the weathering +agencies, whether the winters be open or closed. If for any reason +plowing cannot be done early it is often advantageous to follow the +harvester with a disk and to plow later when convenient. The +chemical effect on the soil resulting from the weathering, made +possible by fall plowing, as will be shown in Chapter IX, is of +itself so great as to warrant the teaching of the general practice +of fall plowing. Secondly, the early stirring of the soil prevents +evaporation of the moisture in the soil during late summer and the +fall. Thirdly, in the parts of the dry-farm territory where much +precipitation occurs in the fall, winter, or early spring, fall +plowing permits much of this precipitation to enter the soil and be +stored there until needed by plants. + +A number of experiment stations have compared plowing done in the +early fall with plowing done late in the fall or in the spring, and +with almost no exception it has been found that early fall plowing +is water-conserving and in other ways advantageous. It was observed +on a Utah dry-farm that the fall-plowed land contained, to a depth +of 10 feet, 7.47 acre-inches more water than the adjoining +spring-plowed land--a saving of nearly one half of a year's +precipitation. The ground should be plowed in the early fall as soon +as possible after the crop is harvested. It should then be left in +the rough throughout the winter, so that it may be mellowed and +broken down by the elements. The rough lend further has a tendency +to catch and hold the snow that may be blown by the wind, thus +insuring a more even distribution of the water from the melting +snow. + +A common objection to fall plowing is that the ground is so dry in +the fall that it does not plow up well, and that the great dry clods +of earth do much to injure the physical condition of the soil. It is +very doubtful if such an objection is generally valid, especially if +the soil is so cropped as to leave a fair margin of moisture in the +soil at harvest time. The atmospheric agencies will usually break +down the clods, and the physical result of the treatment will be +beneficial. Undoubtedly, the fall plowing of dry land is somewhat +difficult, but the good results more than pay the farmer for his +trouble. Late fall plowing, after the fall rains have softened the +land, is preferable to spring plowing. If for any reason the farmer +feels that he must practice spring plowing, he should do it as early +as possible in the spring. Of course, it is inadvisable to plow the +soil when it is so wet as to injure its tilth seriously, but as soon +as that danger period has passed, the plow should be placed in the +ground. The moisture in the soil will thereby be conserved, and +whatever water may fall during the spring months will be conserved +also. This is of especial importance in the Great Plains region and +in any district where the precipitation comes in the spring and +winter months. + +Likewise, after fall plowing, the land must be well stirred in the +early spring with the disk harrow or a similar implement, to enable +the spring rains to enter the soil easily and to prevent the +evaporation of the water already stored. Where the rainfall is quite +abundant and the plowed land has been beaten down by the frequent +rains, the land should be plowed again in the spring. Where such +conditions do not exist, the treatment of the soil with the disk and +harrow in the spring is usually sufficient. + +In recent dry-farm experience it has been fairly completely +demonstrated that, providing the soil is well stored with water, +crops will mature even if no rain falls during the growing season. +Naturally, under most circumstances, any rains that may fall on a +well-prepared soil during the season of crop growth will tend to +increase the crop yield, but some profitable yield is assured, in +spite of the season, if the soil is well stored with water at seed +time. This is an important principle in the system of dry-farming. + + + + + + +CHAPTER VIII + +REGULATING THE EVAPORATION + + + + + +The demonstration in the last chapter that the water which falls as +rain or snow may be stored in the soil for the use of plants is of +first importance in dry-farming, for it makes the farmer +independent, in a large measure, of the distribution of the +rainfall. The dry-farmer who goes into the summer with a soil well +stored with water cares little whether summer rains come or not, for +he knows that his crops will mature in spite of external drouth. In +fact, as will be shown later, in many dry-farm sections where the +summer rains are light they are a positive detriment to the farmer +who by careful farming has stored his deep soil with an abundance of +water. Storing the soil with water is, however, only the first step +in making the rains of fall, winter, or the preceding year available +for plant growth. As soon as warm growing weather comes, +water-dissipating forces come into play, and water is lost by +evaporation. The farmer must, therefore, use all precautions to keep +the moisture in the soil until such time as the roots of the crop +may draw it into the plants to be used in plant production. That is, +as far as possible, direct evaporation of water from the soil must +be prevented. + +Few farmers really realize the immense possible annual evaporation +in the dry-farm territory. It is always much larger than the total +annual rainfall. In fact, an arid region may be defined as one in +which under natural conditions several times more water evaporates +annually from a free water surface than falls as rain and snow. For +that reason many students of aridity pay little attention to +temperature, relative humidity, or winds, and simply measure the +evaporation from a free water surface in the locality in question. +In order to obtain a measure of the aridity, MacDougal has +constructed the following table, showing the annual precipitation +and the annual evaporation at several well-known localities in the +dry-farm territory. + +True, the localities included in the following table are extreme, +but they illustrate the large possible evaporation, ranging from +about six to thirty-five times the precipitation. At the same time +it must be borne in mind that while such rates of evaporation may +occur from free water surfaces, the evaporation from agricultural +soils under like conditions is very much smaller. + + +Place Annual Precipitation Annual Evaporation Ratio + (In Inches) (In Inches) +El Paso, Texas 9.23 80 8.7 +Fort Wingate, +New Mexico 14.00 80 5.7 +Fort Yuma, +Arizona 2.84 100 35.2 +Tucson, AZ 11.74 90 7.7 +Mohave, CA 4.97 95 19.1 +Hawthorne, +Nevada 4.50 80 17.5 +Winnemucca, +Nevada 9.51 80 9.6 +St. George, Utah 6.46 90 13.9 +Fort Duchesne, +Utah 6.49 75 11.6 +Pineville, +Oregon 9.01 70 7.8 +Lost River, +Idaho 8.47 70 8.3 +Laramie, +Wyoming 9.81 70 7.1 +Torres, Mexico 16.97 100 6.0 + + + +To understand the methods employed for checking evaporation from the +soil, it is necessary to review briefly the conditions that +determine the evaporation of water into the air, and the manner in +which water moves in the soil. + +The formation of water vapor + +Whenever water is left freely exposed to the air, it evaporates; +that is, it passes into the gaseous state and mixes with the gases +of the air. Even snow and ice give off water vapor, though in very +small quantities. The quantity of water vapor which can enter a +given volume of air is definitely limited. For instance, at the +temperature of freezing water 2.126 grains of water vapor can enter +one cubic foot of air, but no more. When air contains all the water +possible, it is said to be saturated, and evaporation then ceases. +The practical effect of this is the well-known experience that on +the seashore, where the air is often very nearly fully saturated +with water vapor, the drying of clothes goes on very slowly, whereas +in the interior, like the dry-farming territory, away from the +ocean, where the air is far from being saturated, drying goes on +very rapidly. + +The amount of water necessary to saturate air varies greatly with +the temperature. It is to be noted that as the temperature +increases, the amount of water that may be held by the air also +increases; and proportionately more rapidly than the increase in +temperature. This is generally well understood in common experience, +as in drying clothes rapidly by hanging them before a hot fire. At a +temperature of 100 deg F., which is often reached in portions of the +dry-farm territory during the growing season, a given volume of air +can hold more than nine times as much water vapor as at the +temperature of freezing water. This is an exceedingly important +principle in dry-farm practices, for it explains the relatively easy +possibility of storing water during the fall and winter when the +temperature is low and the moisture usually abundant, and the +greater difficulty of storing the rain that falls largely, as in the +Great Plains area, in the summer when water-dissipating forces are +very active. This law also emphasizes the truth that it is in times +of warm weather that every precaution must be taken to prevent the +evaporation of water from the soil surface. + + +Temperature Grains of Water held in +in Degrees F. One Cubic Foot of Air +32 2.126 +40 2.862 +50 4.089 +60 5.756 +70 7.992 +80 10.949 +90 14.810 +100 19.790 + + +It is of course well understood that the atmosphere as a whole is +never saturated with water vapor. Such saturation is at the best +only local, as, for instance, on the seashore during quiet days, +when the layer of air over the water may be fully saturated, or in a +field containing much water from which, on quiet warm days, enough +water may evaporate to saturate the layer of air immediately upon +the soil and around the plants. Whenever, in such cases, the air +begins to move and the wind blows, the saturated air is mixed with +the larger portion of unsaturated air, and evaporation is again +increased. Meanwhile, it must be borne in mind that into a layer of +saturated air resting upon a field of growing plants very little +water evaporates, and that the chief water-dissipating power of +winds lies in the removal of this saturated layer. Winds or air +movements of any kind, therefore, become enemies of the farmer who +depends upon a limited rainfall. + +The amount of water actually found in a given volume of air at a +certain temperature, compared with the largest amount it can hold, +is called the relative humidity of the air. As shown in Chapter IV, +the relative humidity becomes smaller as the rainfall decreases. The +lower the relative humidity is at a given temperature, the more +rapidly will water evaporate into the air. There is no more striking +confirmation of this law than the fact that at a temperature of 90 +deg sunstrokes and similar ailments are reported in great number +from New York, while the people of Salt Lake City are perfectly +comfortable. In New York the relative humidity in summer is about 73 +per cent; in Salt Lake City, about 35 per cent. At a high summer +temperature evaporation from the skin goes on slowly in New York and +rapidly in Salt Lake City, with the resulting discomfort or comfort. +Similarly, evaporation from soils goes on rapidly under a low and +slowly under a high percentage of relative humidity. + +Evaporation from water surfaces is hastened, therefore, by (1) an +increase in the temperature, (2) an increase in the air movements or +winds, and (3) a decrease in the relative humidity. The temperature +is higher; the relative humidity lower, and the winds usually more +abundant in arid than in humid regions. The dry-farmer must +consequently use all possible precautions to prevent evaporation +from the soil. + +Conditions of evaporation from from soils + +Evaporation does not alone occur from a surface of free water. All +wet or moist substances lose by evaporation most of the water that +they hold, providing the conditions of temperature and relative +humidity are favorable. Thus, from a wet soil, evaporation is +continually removing water. Yet, under ordinary conditions, it is +impossible to remove all the water, for a small quantity is +attracted so strongly by the soil particles that only a temperature +above the boiling point of water will drive it out. This part of the +soil is the hygroscopic moisture spoken of in the last chapter. + +Moreover, it must be kept in mind that evaporation does not occur as +rapidly from wet soil as from a water surface, unless all the soil +pores are so completely filled with water that the soil surface is +practically a water surface. The reason for this reduced evaporation +from a wet soil is almost self-evident. There is a comparatively +strong attraction between soil and water, which enables the moisture +to cling as a thin capillary film around the soil particles, against +the force of gravity. Ordinarily, only capillary water is found in +well-tilled soil, and the force causing evaporation must be strong +enough to overcome this attraction besides changing the water into +vapor. + +The less water there is in a soil, the thinner the water film, and +the more firmly is the water held. Hence, the rate of evaporation +decreases with the decrease in soil-moisture. This law is confirmed +by actual field tests. For instance, as an average of 274 trials +made at the Utah Station, it was found that three soils, otherwise +alike, that contained, respectively, 22.63 per cent, 17.14 per cent, +and 12.75 per cent of water lost in two weeks, to a depth of eight +feet, respectively 21.0, 17. 1, and 10.0 pounds of water per square +foot. Similar experiments conducted elsewhere also furnish proof of +the correctness of this principle. From this point of view the +dry-farmer does not want his soils to be unnecessarily moist. The +dry-farmer can reduce the per cent of water in the soil without +diminishing the total amount of water by so treating the soil that +the water will distribute itself to considerable depths. This brings +into prominence again the practices of fall plowing, deep plowing, +subsoiling, and the choice of deep soils for dry-farming. + +Very much for the same reasons, evaporation goes on more slowly from +water in which salt or other substances have been dissolved. The +attraction between the water and the dissolved salt seems to be +strong enough to resist partially the force causing evaporation. +Soil-water always contains some of the soil ingredients in solution, +and consequently under the given conditions evaporation occurs more +slowly from soil-water than from pure water. Now, the more fertile a +soil is, that is, the more soluble plant-food it contains, the more +material will be dissolved in the soil-water, and as a result the +more slowly will evaporation take place. Fallowing, cultivation, +thorough plowing and manuring, which increase the store of soluble +plant-food, all tend to diminish evaporation. While these conditions +may have little value in the eyes of the farmer who is under an +abundant rainfall, they are of great importance to the dry-farmer. +It is only by utilizing every possibility of conserving water and +fertility that dry-farming may be made a perfectly safe practice. + +Loss by evaporation chiefly at the surface + +Evaporation goes on from every wet substance. Water evaporates +therefore from the wet soil grains under the surface as well as from +those at the surface. In developing a system of practice which will +reduce evaporation to a minimum it must be learned whether the water +which evaporates from the soil particles far below the surface is +carried in large quantities into the atmosphere and thus lost to +plant use. Over forty years ago, Nessler subjected this question to +experiment and found that the loss by evaporation occurs almost +wholly at the soil surface, and that very little if any is lost +directly by evaporation from the lower soil layers. Other +experimenters have confirmed this conclusion, and very recently +Buckingham, examining the same subject, found that while there is a +very slow upward movement of the soil gases into the atmosphere, the +total quantity of the water thus lost by direct evaporation from +soil, a foot below the surface, amounted at most to one inch of +rainfall in six years. This is insignificant even under semiarid and +arid conditions. However, the rate of loss of water by direct +evaporation from the lower soil layers increases with the porosity +of the soil, that is, with the space not filled with soil particles +or water. Fine-grained soils, therefore, lose the least water in +this manner. Nevertheless, if coarse-grained soils are well filled +with water, by deep fall plowing and by proper summer fallowing for +the conservation of moisture, the loss of moisture by direct +evaporation from the lower soil layers need not be larger than from +finer grained soils + +Thus again are emphasized the principles previously laid down that, +for the most successful dry-farming, the soil should always be kept +well filled with moisture, even if it means that the land, after +being broken, must lie fallow for one or two seasons, until a +sufficient amount of moisture has accumulated. Further, the +correlative principle is emphasized that the moisture in dry-farm +lands should be stored deeply, away from the immediate action of the +sun's rays upon the land surface. The necessity for deep soils is +thus again brought out. + +The great loss of soil moisture due to an accumulation of water in +the upper twelve inches is well brought out in the experiments +conducted by the Utah Station. The following is selected from the +numerous data on the subject. Two soils, almost identical in +character, contained respectively 17.57 per cent and 16.55 per cent +of water on an average to a depth of eight feet; that is, the total +amount of water held by the two soils was practically identical. +Owing to varying cultural treatment, the distribution of the water +in the soil was not uniform; one contained 23.22 per cent and the +other 16.64 per cent of water in the first twelve inches. During the +first seven days the soil that contained the highest percentage of +water in the first foot lost 13.30 pounds of water, while the other +lost only 8.48 pounds per square foot. This great difference was due +no doubt to the fact that direct evaporation takes place in +considerable quantity only in the upper twelve inches of soil, where +the sun's heat has a full chance to act. + +Any practice which enables the rains to sink quickly to considerable +depths should be adopted by the dry-farmer. This is perhaps one of +the great reasons for advocating the expensive but usually effective +subsoil plowing on dry-farms. It is a very common experience, in the +arid region, that great, deep cracks form during hot weather. From +the walls of these cracks evaporation goes on, as from the topsoil, +and the passing winds renew the air so that the evaporation may go +on rapidly. The dry-farmer must go over the land as often as needs +be with some implement that will destroy and fill up the cracks that +may have been formed. In a field of growing crops this is often +difficult to do; but it is not impossible that hand hoeing, +expensive as it is, would pay well in the saving of soil moisture +and the consequent increase in crop yield. + +How soil water reaches the surface + +It may be accepted as an established truth that the direct +evaporation of water from wet soils occurs almost wholly at the +surface. Yet it is well known that evaporation from the soil surface +may continue until the soil-moisture to a depth of eight or ten feet +or more is depleted. This is shown by the following analyses of +dry-farm soil in early spring and midsummer. No attempt was made to +conserve the moisture in the soil:-- + + +Per cent of water in Early spring Midsummer +1st foot 20.84 8.83 +2nd foot 20.06 8.87 +3rd foot 19.62 11.03 +4th foot 18.28 9.59 +5th foot 18.70 11.27 +6th foot 14.29 11.03 +7th foot 14.48 8.95 +8th foot 13.83 9.47 +Avg 17.51 9.88 + + +In this case water had undoubtedly passed by capillary movement from +the depth of eight feet to a point near the surface where direct +evaporation could occur. As explained in the last chapter, water +which is held as a film around the soil particles is called +capillary water; and it is in the capillary form that water may be +stored in dry-farm soils. Moreover, it is the capillary +soil-moisture alone which is of real value in crop production. This +capillary water tends to distribute itself uniformly throughout the +soil, in accordance with the prevailing conditions and forces. If no +water is removed from the soil, in course of time the distribution +of the soil-water will be such that the thickness of the film at any +point in the soil mass is a direct resultant of the various forces +acting at that particular point. There will then be no appreciable +movement of the soil-moisture. Such a condition is approximated in +late winter or early spring before planting begins. During the +greater part of the year, however, no such quiescent state can +occur, for there are numerous disturbing elements that normally are +active, among which the three most effective are (l) the addition of +water to the soil by rains; (2) the evaporation of water from the +topsoil, due to the more active meteorological factors during +spring, summer, and fall; and (3) the abstraction of water from the +soil by plant roots. + +Water, entering the soil, moves downward under the influence of +gravity as gravitational water, until under the attractive influence +of the soil it has been converted into capillary water and adheres +to the soil particles as a film. If the soil were dry, and the film +therefore thin, the rain water would move downward only a short +distance as gravitational water; if the soil were wet, and the film +therefore thick, the water would move down to a greater distance +before being exhausted. If, as is often the case in humid districts, +the soil is saturated, that is, the film is as thick as the +particles can hold, the water would pass right through the soil and +connect with the standing water below. This, of course, is seldom +the case in dry-farm districts. In any soil, excepting one already +saturated, the addition of water will produce a thickening of the +soil-water film to the full descent of the water. This immediately +destroys the conditions of equilibrium formerly existing, for the +moisture is not now uniformly distributed. Consequently a process of +redistribution begins which continues until the nearest approach to +equilibrium is restored. In this process water will pass in every +direction from the wet portion of the soil to the drier; it does not +necessarily mean that water will actually pass from the wet portion +to the drier portion; usually, at the driest point a little water is +drawn from the adjoining point, which in turn draws from the next, +and that from the next, until the redistribution is complete. The +process is very much like stuffing wool into a sack which already is +loosely filled. The new wool does not reach the bottom of the sack, +yet there is more wool in the bottom than there was before. + +If a plant-root is actively feeding some distance under the soil +surface, the reverse process occurs. At the feeding point the root +continually abstracts water from the soil grains and thus makes the +film thinner in that locality. This causes a movement of moisture +similar to the one above described, from the wetter portions of the +soil to the portion being dried out by the action of the plant-root. +Soil many feet or even rods distant may assist in supplying such an +active root with moisture. When the thousands of tiny roots sent out +by each plant are recalled. it may well be understood what a +confusion of pulls and counter-pulls upon the soil-moisture exists +in any cultivated soil. In fact, the soil-water film may be viewed +as being in a state of trembling activity, tending to place itself +in full equilibrium with the surrounding contending forces which, +themselves, constantly change. Were it not that the water film held +closely around the soil particles is possessed of extreme mobility, +it would not be possible to meet the demands of the plants upon the +water at comparatively great distances. Even as it is, it frequently +happens that when crops are planted too thickly on dry-farms, the +soil-moisture cannot move quickly enough to the absorbing roots to +maintain plant growth, and crop failure results. Incidentally, this +points to planting that shall be proportional to the moisture +contained by the soil. See Chapter XI. + +As the temperature rises in spring, with a decrease in the relative +humidity, and an increase in direct sunshine, evaporation from the +soil surface increases greatly. However, as the topsoil becomes +drier, that is, as the water fihn becomes thinner, there is an +attempt at readjustment, and water moves upward to take the place of +that lost by evaporation. As this continues throughout the season, +the moisture stored eight or ten feet or more below the surface is +gradually brought to the top and evaporated, and thus lost to plant +use. + +The effect of rapid top drying of soils + +As the water held by soils diminishes, and the water film around the +soil grains becomes thinner, the capillary movement of the +soil-water is retarded. This is easily understood by recalling that +the soil particles have an attraction for water, which is of +definite value, and may be measured by the thickest film that may be +held against gravity. When the film is thinned, it does not diminish +the attraction of the soil for water; it simply results in a +stronger pull upon the water and a firmer holding of the film +against the surfaces of the soil grains. To move soil-water under +such conditions requires the expenditure of more energy than is +necessary for moving water in a saturated or nearly saturated soil. +Under like conditions, therefore, the thinner the soil-water film +the more difficult will be the upward movement of the soil-water and +the slower the evaporation from the topsoil. + +As drying goes on, a point is reached at which the capillary +movement of the water wholly ceases. This is probably when little +more than the hygroscopic moisture remains. In fact, very dry soil +and water repel each other. This is shown in the common experience +of driving along a road in summer, immediately after a light shower. +The masses of dust are wetted only on the outside, and as the wheels +pass through them the dry dust is revealed. It is an important fact +that very dry soil furnishes a very effective protection against the +capillary movement of water. + +In accordance with the principle above established if the surface +soil could be dried to the point where capillarity is very slow, the +evaporation would be diminished or almost wholly stopped. More than +a quarter of a century ago, Eser showed experimentally that +soil-water may be saved by drying the surface soil rapidly. Under +dry-farm conditions it frequently occurs that the draft upon the +water of the soil is so great that nearly all the water is quickly +and so completely abstracted from the upper few inches of soil that +they are left as an effective protection against further +evaporation. For instance, in localities where hot dry winds are of +common occurrence, the upper layer of soil is sometimes completely +dried before the water in the lower layers can by slow capillary +movement reach the top. The dry soil layer then prevents further +loss of water, and the wind because of its intensity has helped to +conserve the soil-moisture. Similarly in localities where the +relative humidity is low, the sunshine abundant, and the temperature +high, evaporation may go on so rapidly that the lower soil layers +cannot supply the demands made, and the topsoil then dries out so +completely as to form a protective covering against further +evaporation. It is on this principle that the native desert soils of +the United States, untouched by the plow, and the surfaces of which +are sun-baked, are often found to possess large percentages of water +at lower depths. Whitney recorded this observation with considerable +surprise, many years ago, and other observers have found the same +conditions at nearly all points of the arid region. This matter has +been subjected to further study by Buckingham, who placed a variety +of soils under artificially arid and humid conditions. It was found +in every case that, the initial evaporation was greater under arid +conditions, but as the process went on and the topsoil of the arid +soil became dry, more water was lost under humid conditions. For the +whole experimental period, also, more water was lost under humid +conditions. It was notable that the dry protective layer was formed +more slowly on alkali soils, which would point to the inadvisability +of using alkali lands for dry-farm purposes. All in all, however, it +appears "that under very arid conditions a soil automatically +protects itself from drying by the formation of a natural mulch on +the surface." + +Naturally, dry-farm soils differ greatly in their power of forming +such a mulch. A heavy clay or a light sandy soil appears to have +less power of such automatic protection than a loamy soil. An +admixture of limestone seems to favor the formation of such a +natural protective mulch. Ordinarily, the farmer can further the +formation of a dry topsoil layer by stirring the soil thoroughly. +This assists the sunshine and the air to evaporate the water very +quickly. Such cultivation is very desirable for other reasons also, +as will soon be discussed. Meanwhile, the water-dissipating forces +of the dry-farm section are not wholly objectionable, for whether +the land be cultivated or not, they tend to hasten the formation of +dry surface layers of soil which guard against excessive +evaporation. It is in moist cloudy weather, when the drying process +is slow, that evaporation causes the greatest losses of +soil-moisture. + +The effect of shading + +Direct sunshine is, next to temperature, the most active cause of +rapid evaporation from moist soil surfaces. Whenever, therefore, +evaporation is not rapid enough to form a dry protective layer of +topsoil, shading helps materially in reducing surface losses of +soil-water. Under very arid conditions, however, it is questionable +whether in all cases shading has a really beneficial effect, though +under semiarid or sub-humid conditions the benefits derived from +shading are increased largely. Ebermayer showed in 1873 that the +shading due to the forest cover reduced evaporation 62 per cent, and +many experiments since that day have confirmed this conclusion. At +the Utah Station, under arid conditions, it was found that shading a +pot of soil, which otherwise was subjected to water-dissipating +influences, saved 29 per cent of the loss due to evaporation from a +pot which was not shaded. This principle cannot be applied very +greatly in practice, but it points to a somewhat thick planting, +proportioned to the water held by the soil. It also shows a possible +benefit to be derived from the high header straw which is allowed to +stand for several weeks in dry-farm sections where the harvest comes +early and the fall plowing is done late, as in the mountain states. +The high header stubble shades the ground very thoroughly. Thus the +stubble may be made to conserve the soil-moisture in dry-farm +sections, where grain is harvested by the "header" method. + +A special case of shading is the mulching of land with straw or +other barnyard litter, or with leaves, as in the forest. Such +mulching reduces evaporation, but only in part, because of its +shading action, since it acts also as a loose top layer of soil +matter breaking communication with the lower soil layers. + +Whenever the soil is carefully stirred, as will be described, the +value of shading as a means or checking evaporation disappears +almost entirely. It is only with soils which are tolerably moist at +the surface that shading acts beneficially. + +Alfalfa in cultivated rows. This practice is employed to make +possible the growth of alfalfa and other perennial crops on arid +lands without irrigation. + +The effect of tillage + +Capillary soil-moisture moves from particle to particle until the +surface is reached. The closer the soil grains are packed together, +the greater the number of points or contact, and the more easily +will the movement of the soil-moisture proceed. If by any means a +layer of the soil is so loosened as to reduce the number of points +of contact, the movement of the soil-moisture is correspondingly +hindered. The process is somewhat similar to the experience in large +r airway stations. Just before train time a great crowd of people is +gathered outside or the gates ready to show their tickets. If one +gate is opened, a certain number of passengers can pass through each +minute; if two are opened, nearly twice as many may be admitted in +the same time; if more gates are opened, the passengers will be able +to enter the train more rapidly. The water in the lower layers of +the soil is ready to move upward whenever a call is made upon it. To +reach the surface it must pass from soil grain to soil grain, and +the larger the number of grains that touch, the more quickly and +easily will the water reach the surface, for the points of contact +of the soil particles may be likened to the gates of the railway +station. Now if, by a thorough stirring and loosening of the +topsoil, the number of points of contact between the top and subsoil +is greatly reduced, the upward flow of water is thereby largely +checked. Such a loosening of the topsoil for the purpose of reducing +evaporation from the topsoil has come to be called cultivation, and +includes plowing, harrowing, disking, hoeing, and other cultural +operations by which the topsoil is stirred. The breaking of the +points of contact between the top and subsoil is undoubtedly the +main reason for the efficiency of cultivation, but it is also to be +remembered that such stirring helps to dry the top soil very +thoroughly, and as has been explained a layer of dry soil of itself +is a very effective check upon surface evaporation. + +That the stirring or cultivation of the topsoil really does diminish +evaporation of water from the soil has been shown by numerous +investigations. In 1868, Nessler found that during six weeks of an +ordinary German summer a stirred soil lost 510 grams of water per +square foot, while the adjoining compacted soil lost 1680 grams,--a +saving due to cultivation of nearly 60 per cent. Wagner, testing the +correctness of Nessler's work, found, in 1874, that cultivation +reduced the evaporation a little more than 60 per cent; Johnson, in +1878, confirmed the truth of the principle on American soils, and +Levi Stockbridge, working about the same time, also on American +soils, found that cultivation diminished evaporation on a clay soil +about 23 per cent, on a sandy loam 55 per cent, and on a heavy loam +nearly 13 per cent. All the early work done on this subject was done +under humid conditions, and it is only in recent years that +confirmation of this important principle has been obtained for the +soils of the dry-farm region. Fortier, working under California +conditions, determined that cultivation reduced the evaporation from +the soil surface over 55 per cent. At the Utah Station similar +experiments have shown that the saving of soil-moisture by +cultivation was 63 per cent for a clay soil, 34 per cent for a +coarse sand, and 13 per cent for a clay loam. Further, practical +experience has demonstrated time and time again that in cultivation +the dry-farmer has a powerful means of preventing evaporation from +agricultural soils. + +Closely connected with cultivation is the practice of scattering +straw or other litter over the ground. Such artificial mulches are +very effective in reducing evaporation. Ebermayer found that by +spreading straw on the land, the evaporation was reduced 22 per +cent; Wagner found under similar conditions a saving of 38 per cent, +and these results have been confirmed by many other investigators. +On the modern dry-farms, which are large in area, the artificial +mulching of soils cannot become a very extensive practice, yet it is +well to bear the principle in mind. The practice of harvesting +dry-farm grain with the header and plowing under the high stubble in +the fall is a phase of cultivation for water conservation that +deserves special notice. The straw, thus incorporated into the soil, +decomposes quite readily in spite of the popular notion to the +contrary, and makes the soil more porous, and, therefore, more +effectively worked for the prevention of evaporation. When this +practice is continued for considerable periods, the topsoil becomes +rich in organic matter, which assists in retarding evaporation, +besides increasing the fertility of the land. When straw cannot be +fed to advantage, as is yet the case on many of the western +dry-farms, it would be better to scatter it over the land than to +burn it, as is often done. Anything that covers the ground or +loosens the topsoil prevents in a measure the evaporation of the +water stored in lower soil depths for the use of crops. + +Depth of cultivation + +The all-important practice for the dry-farmer who is entering upon +the growing season is cultivation. The soil must be covered +continually with a deep layer of dry loose soil, which because of +its looseness and dryness makes evaporation difficult. A leading +question in connection with cultivation is the depth to which the +soil should be stirred for the best results. Many of the early +students of the subject found that a soil mulch only one half inch +in depth was effective in retaining a large part of the +soil-moisture which noncultivated soils would lose by evaporation. +Soils differ greatly in the rate of evaporation from their surfaces. +Some form a natural mulch when dried, which prevents further water +loss. Others form only a thin hard crust, below which lies an active +evaporating surface of wet soil. Soils which dry out readily and +crumble on top into a natural mulch should be cultivated deeply, for +a shallow cultivation does not extend beyond the naturally formed +mulch. In fact, on certain calcareous soils, the surfaces of which +dry out quickly and form a good protection against evaporation, +shallow cultivations often cause a greater evaporation by disturbing +the almost perfect natural mulch. Clay or sand soils, which do not +so well form a natural mulch, will respond much better to shallow +cultivations. In general, however, the deeper the cultivation, the +more effective it is in reducing evaporation. Fortier, in the +experiments in California to which allusion has already been made, +showed the greater value of deep cultivation. During a period of +fifteen days, beginning immediately after an irrigation, the soil +which had not been mulched lost by evaporation nearly one fourth of +the total amount of water that had been added. A mulch 4 inches deep +saved about 72 per cent of the evaporation; a mulch 8 inches deep +saved about 88 per cent, and a mulch 10 inches deep stopped +evaporation almost wholly. It is a most serious mistake for the +dry-farmer, who attempts cultivation for soil-moisture conservation, +to fail to get the best results simply to save a few cents per acre +in added labor. + +When to cultivate or till + +It has already been shown that the rate of evaporation is greater +from a wet than from a dry surface. It follows, therefore, that the +critical time for preventing evaporation is when the soil is +wettest. After the soil is tolerably dry, a very large portion of +the soil-moisture has been lost, which possibly might have been +saved by earlier cultivation. The truth of this statement is well +shown by experiments conducted by the Utah Station. In one case on a +soil well filled with water, during a three weeks' period, nearly +one half of the total loss occurred the first, while only one fifth +fell on the third week. Of the amount lost during the first week, +over 60 per cent occurred during the first three days. Cultivation +should, therefore, be practiced as soon as possible after conditions +favorable for evaporation have been established. This means, first, +that in early spring, just as soon as the land is dry enough to be +worked without causing puddling, the soil should be deeply and +thoroughly stirred. Spring plowing, done as early as possible, is an +excellent practice for forming a mulch against evaporation. Even +when the land has been fall-plowed, spring plowing is very +beneficial, though on fall-plowed land the disk harrow is usually +used in early spring, and if it is set at rather a sharp angle, and +properly weighted, so that it cuts deeply into the ground, it is +practically as effective as spring plowing. The chief danger to the +dry-farmer is that he will permit the early spring days to slip by +until, when at last he begins spring cultivation, a large portion of +the stored soil-water has been evaporated. It may be said that deep +fall plowing, by permitting the moisture to sink quickly into the +lower layers of soil, makes it possible to get upon the ground +earlier in the spring. In fact, unplowed land cannot be cultivated +as early as that which has gone through the winter in a plowed +condition + +If the land carries a fall-sown crop, early spring cultivation is +doubly important. As soon as the plants are well up in spring the +land should be gone over thoroughly several times if necessary, with +an iron tooth harrow, the teeth of which are set to slant backward +in order not to tear up the plants. The loose earth mulch thus +formed is very effective in conserving moisture; and the few plants +torn up are more than paid for by the increased water supply for the +remaining plants. The wise dry-fanner cultivates his land, whether +fallow or cropped, as early as possible in the spring. + +Following the first spring plowing, disking, or cultivation, must +come more cultivation. Soon after the spring plowing, the land +should be disked and. then harrowed. Every device should be used to +secure the formation of a layer of loose drying soil over the land +surface. The season's crop will depend largely upon the +effectiveness of this spring treatment. + +As the season advances, three causes combine to permit the +evaporation of soil-moisture. + +First, there is a natural tendency, under the somewhat moist +conditions of spring, for the soil to settle compactly and thus to +restore the numerous capillary connections with the lower soil +layers through which water escapes. Careful watch should therefore +be kept upon the soil surface, and whenever the mulch is not loose, +the disk or harrow should be run over the land. + +Secondly, every rain of spring or summer tends to establish +connections with the store of moisture in the soil. In fact, late +spring and summer rains are often a disadvantage on dry-farms, which +by cultural treatment have been made to contain a large store of +moisture. It has been shown repeatedly that light rains draw +moisture very quickly from soil layers many feet below the surface. +The rainless summer is not feared by the dry-farmer whose soils are +fertile and rich in moisture. It is imperative that at the very +earliest moment after a spring or summer rain the topsoil be well +stirred to prevent evaporation. It thus happens that in sections of +frequent summer rains, as in the Great Plains area, the farmer has +to harrow his land many times in succession, but the increased crop +yields invariably justify the added expenditure of effort. + +Thirdly, on the summer-fallowed ground weeds start vigorously in the +spring and draw upon the soil-moisture, if allowed to grow, fully as +heavily as a crop of wheat or corn. The dry-farmer must not allow a +weed upon his land. Cultivation must he so continuous as to make +weeds an impossibility. The belief that the elements added to the +soil by weeds offset the loss of soil-moisture is wholly erroneous. +The growth of weeds on a fallow dry-farm is more dangerous than the +packed uncared-for topsoil. Many implements have been devised for +the easy killing of weeds, but none appear to be better than the +plow and the disk which are found on every farm. (See Chapter XV.) + +When crops are growing on the land, thorough summer cultivation is +somewhat more difficult, but must be practiced for the greatest +certainty of crop yields. Potatoes, corn, and similar crops may be +cultivated with comparative ease, by the use of ordinary +cultivators. With wheat and the other small grains, generally, the +damage done to the crop by harrowing late in the season is too +great, and reliance is therefore placed on the shading power of the +plants to prevent undue evaporation. However, until the wheat and +other grains are ten to twelve inches high, it is perfectly safe to +harrow them. The teeth should be set backward to diminish the +tearing up of the plants, and the implement weighted enough to break +the soil crust thoroughly. This practice has been fully tried out +over the larger part of the dry-farm territory and found +satisfactory. + +So vitally important is a permanent soil mulch for the conservation +for plant use of the water stored in the soil that many attempts +have been made to devise means for the effective cultivation of land +on which small grains and grasses are growing. In many places plants +have been grown in rows so far apart that a man with a hoe could +pass between them. Scofield has described this method as practiced +successfully in Tunis. Campbell and others in America have proposed +that a drill hole be closed every three feet to form a path wide +enough for a horse to travel in and to pull a large spring tooth +cultivator' with teeth so spaced as to strike between the rows of +wheat. It is yet doubtful whether, under average conditions, such +careful cultivation, at least of grain crops, is justified by the +returns. Under conditions of high aridity, or where the store of +soil-moisture is low, such treatment frequently stands between crop +success and failure, and it is not unlikely that methods will be +devised which will permit of the cheap and rapid cultivation between +the rows of growing wheat. Meanwhile, the dry-farmer must always +remember that the margin under which he works is small, and that his +success depends upon the degree to which he prevents small wastes. + +Dry-farm potatoes, Rosebud Co., Montana, 1909. Yield, 282 bushels +per acre. + +The conservation of soil-moisture depends upon the vigorous, +unremitting, continuous stirring of the topsoil. Cultivation! +cultivation! and more cultivation! must be the war-cry of the +dry-farmer who battles against the water thieves of an arid climate. + + + + + + +CHAPTER IX + +REGULATING THE TRANSPIRATION + + + + + +Water that has entered the soil may be lost in three ways. First, it +may escape by downward seepage, whereby it passes beyond the reach +of plant roots and often reaches the standing water. In dry-farm +districts such loss is a rare occurrence, for the natural +precipitation is not sufficiently large to connect with the country +drainage, and it may, therefore, be eliminated from consideration. +Second, soil-water may be lost by direct evaporation from the +surface soil. The conditions prevailing in arid districts favor +strongly this manner of loss of soil-moisture. It has been shown, +however, in the preceding chapter that the farmer, by proper and +persistent cultivation of the topsoil, has it in his power to reduce +this loss enough to be almost negligible in the farmer's +consideration. Third, soil-water may be lost by evaporation from the +plants themselves. While it is not generally understood, this source +of loss is, in districts where dry-farming is properly carried on, +very much larger than that resulting either from seepage or from +direct evaporation. While plants are growing, evaporation from +plants, ordinarily called transpiration, continues. Experiments +performed in various arid districts have shown that one and a half +to three times more water evaporates from the plant than directly +from well-tilled soil. To the present very little has been learned +concerning the most effective methods of checking or controlling +this continual loss of water. Transpiration, or the evaporation of +water from the plants themselves and the means of controlling this +loss, are subjects of the deepest importance to the dry-farmer. + +Absorption + +To understand the methods for reducing transpiration, as proposed in +this chapter, it is necessary to review briefly the manner in which +plants take water from the soil. The roots are the organs of water +absorption. Practically no water is taken into the plants by the +stems or leaves, even under conditions of heavy rainfall. Such small +quantities as may enter the plant through the stems and leaves are +of very little value in furthering the life and growth of the plant. +The roots alone are of real consequence in water absorption. All +parts of the roots do not possess equal power of taking up +soil-water. In the process of water absorption the younger roots are +most active and effective. Even of the young roots, however, only +certain parts are actively engaged in water absorption. At the very +tips of the young growing roots are numerous fine hairs. These +root-hairs, which cluster about the growing point of the young +roots, are the organs of the plant that absorb soil-water. They are +of value only for limited periods of time, for as they grow older, +they lose their power of water absorption. In fact, they are active +only when they are in actual process of growth. It follows, +therefore, that water absorption occurs near the tips of the growing +roots, and whenever a plant ceases to grow the water absorption +ceases also. The root-hairs are filled with a dilute solution of +various substances, as yet poorly understood, which plays an +important tent part in the ab sorption of water and plant-food from +the soil. + +Owing to their minuteness, the root-hairs are in most cases immersed +in the water film that surrounds the soil particles, and the +soil-water is taken directly into the roots from the soil-water film +by the process known as osmosis. The explanation of this inward +movement is complicated and need not be discussed here. It is +sufficient to say that the concentration or strength of the solution +within the root-hair is of different degree from the soil-water +solution. The water tends, therefore, to move from the soil into the +root, in order to make the solutions inside and outside of the root +of the same concentration. If it should ever occur that the +soil-water and the water within the root-hair became the same +concentration, that is to say, contained the same substances in the +same proportional amounts, there would be no further inward movement +of water. Moreover, if it should happen that the soil-water is +stronger than the water within the root-hair, the water would tend +to pass from the plant into the soil. This is the condition that +prevails in many alkali lands of the West, and is the cause of the +death of plants growing on such lands. + +It is clear that under these circumstances not only water enters the +root-hairs, but many of the substances found in solution in the +soil-water enter the plant also. Among these are the mineral +substances which are indispensable for the proper life and growth of +plants. These plant nutrients are so indispensable that if any one +of them is absent, it is absolutely impossible for the plant to +continue its life functions. The indispensable plant-foods gathered +from the soil by the root-hairs, in addition to water, are: +potassium, calcium, magnesium, iron, nitrogen, and phosphorus,--all +in their proper combinations. How the plant uses these substances is +yet poorly understood, but we are fairly certain that each one has +some particular function in the life of the plant. For instance, +nitrogen and phosphorus are probably necessary in the formation of +the protein or the flesh-forming portions of the plant, while potash +is especially valuable in the formation of starch. + +There is a constant movement of the indispensable plant nutrients +after they have entered the root-hairs, through the stems and into +the leaves. This constant movement of the plant-foods depends upon +the fact that the plant consumes in its growth considerable +quantities of these substances, and as the plant juices are +diminished in their content of particular plant-foods, more enters +from the soil solution. The necessary plant-foods do not alone enter +the plant but whatever may be in solution in the soil-water enters +the plant in variable quantities. Nevertheless, since the plant uses +only a few definite substances and leaves the unnecessary ones in +solution, there is soon a cessation of the inward movement of the +unimportant constituents of the soil solution. This process is often +spoken of as selective absorption; that is, the plant, because of +its vital activity, appears to have the power of selecting from the +soil certain substances and rejecting others. + +Movement of water through plant + +The soil-water, holding in solution a great variety of plant +nutrients, passes from the root-hairs into the adjoining cells and +gradually moves from cell to cell throughout the whole plant. In +many plants this stream of water does not simply pass from cell to +cell, but moves through tubes that apparently have been formed for +the specific purpose of aiding the movement of water through the +plant. The rapidity of this current is often considerable. +Ordinarily, it varies from one foot to six feet per hour, though +observations are on record showing that the movement often reaches +the rate of eighteen feet per hour. It is evident, then, that in an +actively growing plant it does not take long for the water which is +in the soil to find its way to the uppermost parts of the plant. + +The work of leaves + +Whether water passes upward from cell to cell or through especially +provided tubes, it reaches at last the leaves, where evaporation +takes place. It is necessary to consider in greater detail what +takes place in leaves in order that we may more clearly understand +the loss due to transpiration. One half or more of every plant is +made up of the element carbon. The remainder of the plant consists +of the mineral substances taken from the soil (not more than two to +10 per cent of the dry plant) and water which has been combined with +the carbon and these mineral substances to form the characteristic +products of plant life. The carbon which forms over half of the +plant substance is gathered from the air by the leaves and it is +evident that the leaves are very active agents of plant growth. The +atmosphere consists chiefly of the gases oxygen and nitrogen in the +proportion of one to four, but associated with them are small +quantities of various other substances. Chief among the secondary +constituents of the atmosphere is the gas carbon dioxid, which is +formed when carbon burns, that is, when carbon unites with the +oxygen of the air. Whenever coal or wood or any carbonaceous +substance burns, carbon dioxid is formed. Leaves have the power of +absorbing the gas carbon dioxid from the air and separating the +carbon from the oxygen. The oxygen is returned to the atmosphere +while the carbon is retained to be used as the fundamental substance +in the construction by the plant of oils, fats, starches, sugars, +protein, and all the other products of plant growth. + +This important process known as carbon assimilation is made possible +by the aid of countless small openings which exist chicfly on the +surfaces of leaves and known as "stomata." The stomata are +delicately balanced valves, exceedingly sensitive to external +influences. They are more numerous on the lower side than on the +upper side of plants. In fact, there is often five times more on the +under side than on the upper side of a leaf. It has been estimated +that 150,000 stomata or more are often found per square inch on the +under side of the leaves of ordinary cultivated plants. The stomata +or breathing-pores are so constructed that they may open and close +very readily. In wilted leaves they are practically closed; often +they also close immediately after a rain; but in strong sunlight +they are usually wide open. It is through the stomata that the gases +of the air enter the plant through which the discarded oxygen +returns to the atmosphere. + +It is also through the stomata that the water which is drawn from +the soil by the roots through the stems is evaporated into the air. +There is some evaporation of water from the stems and branches of +plants, but it is seldom more than a thirtieth or a fortieth of the +total transpiration. The evaporation of water from the leaves +through the breathing-pores is the so-called transpiration, which is +the greatest cause of the loss of soil-water under dry-farm +conditions. It is to the prevention of this transpiration that much +investigation must be given by future students of dry-farming. + +Transpiration + +As water evaporates through the breathing-pores from the leaves it +necessarily follows that a demand is made upon the lower portions of +the plant for more water. The effect of the loss of water is felt +throughout the whole plant and is, undoubtedly, one of the chief +causes of the absorption of water from the soil. As evaporation is +diminished the amount of water that enters the plants is also +diminished. Yet transpiration appears to be a process wholly +necessary for plant life. The question is, simply, to what extent it +may be diminished without injuring plant growth. Many students +believe that the carbon assimilation of the plant, which is +fundamentally important in plant growth, cannot be continued unless +there is a steady stream of water passing through the plant and then +evaporating from the leaves. + +Of one thing we are fairly sure: if the upward stream of water is +wholly stopped for even a few hours, the plant is likely to be so +severely injured as to be greatly handicapped in its future growth. + +Botanical authorities agree that transpiration is of value to plant +growth, first, because it helps to distribute the mineral nutrients +necessary for plant growth uniformly throughout the plant; secondly, +because it permits an active assimilation of the carbon by the +leaves; thirdly, because it is not unlikely that the heat required +to evaporate water, in large part taken from the plant itself, +prevents the plant from being overheated. This last mentioned value +of transpiration is especially important in dry-farm districts, +where, during the summer, the heat is often intense. Fourthly, +transpiration apparently influences plant growth and development in +a number of ways not yet clearly understood. + +Conditions influencing transpiration + +In general, the conditions that determine the evaporation of water +from the leaves are the same as those that favor the direct +evaporation of water from soils, although there seems to be +something in the life process of the plant, a physiological factor, +which permits or prevents the ordinary water-dissipating factors +from exercising their full powers. That the evaporation of water +from the soil or from a free water surface is not the same as that +from plant leaves may be shown in a general way from the fact that +the amount of water transpired from a given area of leaf surface may +be very much larger or very much smaller than that evaporated from +an equal surface of free water exposed to the same conditions. It is +further shown by the fact that whereas evaporation from a free water +surface goes on with little or no interruption throughout the +twenty-four hours of the day, transpiration is virtually at a +standstill at night even though the conditions for the rapid +evaporation from a free water surface are present. + +Some of the conditions influencing the transpiration may be +enumerated as follows:-- + +First, transpiration is influenced by the relative humidity. In dry +air, under otherwise similar conditions, plants transpire more water +than in moist air though it is to be noted that even when the +atmosphere is fully saturated, so that no water evaporates from a +free water surface, the transpiration of plants still continues in a +small degree. This is explained by the observation that since the +life process of a plant produces a certain amount of heat, the plant +is always warmer than the surrounding air and that transpiration +into an atmosphere fully charged with water vapor is consequently +made possible. The fact that transpiration is greater under a low +relative humidity is of greatest importance to the dry-farmer who +has to contend with the dry atmosphere. + +Second, transpiration increases with the increase in temperature; +that is, under conditions otherwise the same, transpiration is more +rapid on a warm day than on a cold one. The temperature increase of +itself, however, is not sufficient to cause transpiration. + +Third, transpiration increases with the increase of air currents, +which is to say, that on a windy day transpiration is much more +rapid than on a quiet day. + +Fourth, transpiration increases with the increase of direct +sunlight. It is an interesting observation that even with the same +relative humidity, temperature, and wind, transpiration is reduced +to a minimum during the night and increases manyfold during the day +when direct sunlight is available. This condition is again to be +noted by the dry-farmer, for the dry-farm districts are +characterized by an abundance of sunshine. + +Fifth, transpiration is decreased by the presence in the soil-water +of large quantities of the substances which the plant needs for its +food material. This will be discussed more fully in the next +section. + +Sixth, any mechanical vibration of the plant seems to have some +effect upon the transpiration. At times it is increased and at times +it is decreased by such mechanical disturbance. + +Seventh, transpiration varies also with the age of the plant. In the +young plant it is comparatively small. Just before blooming it is +very much larger and in time of bloom it is the largest in the +history of the plant. As the plant grows older transpiration +diminishes, and finally at the ripening stage it almost ceases. + +Eighth, transpiration varies greatly with the crop. Not all plants +take water from the soil at the same rate. Very little is as yet +known about the relative water requirements of crops on the basis of +transpiration. As an illustration, MacDougall has reported that +sagebrush uses about one fourth as much water as a tomato plant. +Even greater differences exist between other plants. This is one of +the interesting subjects yet to be investigated by those who are +engaged in the reclamation of dry-farm districts. Moreover, the same +crop grown under different conditions varies in its rate of +transpiration. For instance, plants grown for some time under arid +conditions greatly modify their rate of transpiration, as shown by +Spalding, who reports that a plant reared under humid conditions +gave off 3.7 times as much water as the same plant reared under arid +conditions. This very interesting observation tends to confirm the +view commonly held that plants grown under arid conditions will +gradually adapt themselves to the prevailing conditions, and in +spite of the greater water dissipating conditions will live with the +expenditure of less water than would be the case under humid +conditions. Further, Sorauer found, many years ago, that different +varieties of the same crop possess very different rates of +transpiration. This also is an interesting subject that should be +more fully investigated in the future. + +Ninth, the vigor of growth of a crop appears to have a strong +influence on transpiration. It does not follow, however, that the +more vigorously a crop grows, the more rapidly does it transpire +water, for it is well known that the most luxuriant plant growth +occurs in the tropics, where the transpiration is exceedingly low. +It seems to be true that under the same conditions, plants that grow +most vigorously tend to use proportionately the smallest amount of +water. + +Tenth, the root system--its depth and manner of growth--influences +the rate of transpiration. The more vigorous and extensive the root +system, the more rapidly can water be secured from the soil by the +plant. + +The conditions above enumerated as influencing transpiration are +nearly all of a physical character, and it must not be forgotten +that they may all be annulled or changed by a physiological +regulation. It must be admitted that the subject of transpiration is +yet poorly understood, though it is one of the most important +subjects in its applications to plant production in localities where +water is scaree. It should also be noted that nearly all of the +above conditions influencing transpiration are beyond the control of +the farmer. The one that seems most readily controlled in ordinary +agricultural practice will be discussed in the following section. + +Plant-food and transpiration + +It has been observed repeatedly by students of transpiration that +the amount of water which actually evaporates from the leaves is +varied materially by the substances held in solution by the +soil-water. That is, transpiration depends upon the nature and +concentration of soil solution. This fact, though not commonly +applied even at the present time, has really been known for a very +long time. Woodward, in 1699, observed that the amount of water +transpired by a plant growing in rain water was 192.3 grams; in +spring water, 163.6 grams, and in water from the River Thames, 159.5 +grams; that is, the amount of water transpired by the plant in the +comparatively pure rain water was nearly 20 per cent higher than +that used by the plant growing in the notoriously impure water of +the River Thames. Sachs, in 1859, carried on an elaborate series of +experiments on transpiration in which he showed that the addition of +potassium nitrate, ammonium sulphate or common salt to the solution +in which plants grew reduced the transpiration; in fact, the +reduction was large, varying from 10 to 75 per cent. This was +confirmed by a number of later workers, among them, for instance, +Buergerstein, who, in 1875, showed that whenever acids were added to +a soil or to water in which plants are growing, the transpiration is +increased greatly; but when alkalies of any kind are added, +transpiration decreases. This is of special interest in the +development of dry-farming, since dry-farm soils, as a rule, contain +more substances that may be classed as alkalies than do soils +maintained under humid conditions. Sour soils are very +characteristic of districts where the rainfall is abundant; the +vegetation growing on such soils transpires excessively and the +crops are consequently more subject to drouth. + +The investigators of almost a generation ago also determined beyond +question that whenever a complete nutrient solution is presented to +plants, that is, a solution containing all the necessary plant-foods +in the proper proportions, the transpiration is reduced immensely. +It is not necessary that the plant-foods should be presented in a +water solution in order to effect this reduction in transpiration; +if they are added to the soil on which plants are growing, the same +effect will result. The addition of commercial fertilizers to the +soil will therefore diminish transpiration. It was further +discovered nearly half a century ago that similar plants growing on +different soils evaporate different amounts of water from their +leaves; this difference, undoubtedly, is due to the conditions in +the fertility of the soils, for the more fertile a soil is, the +richer will the soil-water be in the necessary plant-foods. The +principle that transpiration or the evaporation of water from the +plants depends on the nature and concentration of the soil solution +is of far-reaching importance in the development of a rational +practice of dry-farming. + +Transpiration for a pound of dry matter + +Is plant growth proportional to transpiration? Do plants that +evaporate much water grow more rapidly than those that evaporate +less? These questions arose very early in the period characterized +by an active study of transpiration. If varying the transpiration +varies the growth, there would be no special advantage in reducing +the transpiration. From an economic point of view the important +question is this: Does the plant when its rate of transpiration is +reduced still grow with the same vigor? If that be the case, then +every effort should be made by the farmer to control and to diminish +the rate of transpiration. + +One of the very earliest experiments on transpiration, conducted by +Woodward in 1699, showed that it required less water to produce a +pound of dry matter if the soil solution were of the proper +concentration and contained the elements necessary for plant growth. +Little more was done to answer the above questions for over one +hundred and fifty years. Perhaps the question was not even asked +during this period, for scientific agriculture was just coming into +being in countries where the rainfall was abundant. However, +Tschaplowitz, in 1878, investigated the subject and found that the +increase in dry matter is greatest when the transpiration is the +smallest. Sorauer, in researches conducted from 1880 to 1882, +determined with almost absolute certainty that less water is +required to produce a pound of dry matter when the soil is +fertilized than when it is not fertilized. Moreover, he observed +that the enriching of the soil solution by the addition of +artificial fertilizers enabled the plant to produce dry matter with +less water. He further found that if a soil is properly tilled so as +to set free plant-food and in that way to enrich the soil solution +the water-cost of dry plant substance is decreased. Hellriegel, in +1883, confirmed this law and laid down the law that poor plant +nutrition increases the water-cost of every pound of dry matter +produced. It was about this time that the Rothamsted Experiment +Station reported that its experiments had shown that during periods +of drouth the well-tilled and well-fertilized fields yielded good +crops, while the unfertilized fields yielded poor crops or crop +failures--indicating thereby, since rainfall was the critical +factor, that the fertility of the soil is important in determining +whether or not with a small amount of water a good crop can be +produced. Pagnoul, working in 1895 with fescue grass, arrived at the +same conclusion. On a poor clay soil it required 1109 pounds of +water to produce one pound of dry matter, while on a rich calcareous +soil only 574 pounds were required. Gardner of the United States +Department of Agriculture, Bureau of Soils, working in 1908, on the +manuring of soils, came to the conclusion that the more fertile the +soil the less water is required to produce a pound of dry matter. He +incidentally called attention to the fact that in countries of +limited rainfall this might be a very important principle to apply +in crop production. Hopkins in his study of the soils of Illinois +has repeatedly observed, in connection with certain soils, that +where the land is kept fertile, injury from drouth is not common, +implying thereby that fertile soils will produce dry matter at a +lower water-cost. The most recent experiments on this subject, +conducted by the Utah Station, confirm these conclusions. The +experiments, which covered several years, were conducted in pots +filled with different soils. On a soil, naturally fertile, 908 +pounds of water were transpired for each pound of dry matter (corn) +produced; by adding to this soil an ordinary dressing of manure' +this was reduced to 613 pounds, and by adding a small amount of +sodium nitrate it was reduced to 585 pounds. If so large a reduction +could be secured in practice, it would seem to justify the use of +commercial fertilizers in years when the dry-farm year opens with +little water stored in the soil. Similar results, as will be shown +below, were obtained by the use of various cultural methods. It may +therefore, be stated as a law, that any cultural treatment which +enables the soil-water to acquire larger quantities of plant-food +also enables the plant to produce dry matter with the use of a +smaller amount of water. In dry-farming, where the limiting factor +is water, this principle must he emphasized in every cultural +operation. + +Methods of controlling transpiration + +It would appear that at present the only means possessed by the +farmer for controlling transpiration and making possible maximum +crops with the minimum amount of water in a properly tilled soil is +to keep the soil as fertile as is possible. In the light of this +principle the practices already recommended for the storing of water +and for the prevention of the direct evaporation of water from the +soil are again emphasized. Deep and frequent plowing, preferably in +the fall so that the weathering of the winter may be felt deeply and +strongly, is of first importance in liberating plant-food. +Cultivation which has been recommended for the prevention of the +direct evaporation of water is of itself an effective factor in +setting free plant-food and thus in reducing the amount of water +required by plants. The experiments at the Utah Station, already +referred to, bring out very strikingly the value of cultivation in +reducing the transpiration. For instance, in a series of experiments +the following results were obtained. On a sandy loam, not +cultivated, 603 pounds of water were transpired to produce one pound +of dry matter of corn; on the same soil, cultivated, only 252 pounds +were required. On a clay loam, not cultivated, 535 pounds of water +were transpired for each pound of dry matter, whereas on the +cultivated soil only 428 pounds were necessary. On a clay soil, not +cultivated, 753 pounds of water were transpired for each pound of +dry matter; on the cultivated soil, only 582 pounds. The farmer who +faithfully cultivates the soil throughout the summer and after every +rain has therefore the satisfaction of knowing that he is +accomplishing two very important things: he is keeping the moisture +in the soil, and he is making it possible for good crops to be grown +with much less water than would otherwise be required. Even in the +case of a peculiar soil on which ordinary cultivation did not reduce +the direct evaporation, the effect upon the transpiration was very +marked. On the soil which was not cultivated, 451 pounds of water +were required to produce one pound of dry matter (corn), while on +the cultivated soils, though the direct evaporation was no smaller, +the number of pounds of water for each pound of dry substance was as +low as 265. + +One of the chief values of fallowing lies in the liberation of the +plant-food during the fallow year, which reduces the quantity of +water required the next year for the full growth of crops. The Utah +experiments to which reference has already been made show the effect +of the previous soil treatment upon the water requirements of crops. +One half of the three types of soil had been cropped for three +successive years, while the other half had been left bare. During +the fourth year both halves were planted to corn. For the sandy loam +it was found that, on the part that had been cropped previously, 659 +pounds of water were required for each pound of dry matter produced, +while on the part that had been bare only 573 pounds were required. +For the clay loam 889 pounds on the cropped part and 550 on the +previously bare part were required for each pound of dry matter. For +the clay 7466 pounds on the cropped part and 1739 pounds on the +previously bare part were required for each pound of dry matter. +These results teach clearly and emphatically that the fertile +condition of the soil induced by fallowing makes it possible to +produce dry matter with a smaller amount of water than can be done +on soils that are cropped continuously. The beneficial effects of +fallowing are therefore clearly twofold: to store the moisture of +two seasons for the use of one crop; and to set free fertility to +enable the plant to grow with the least amount of water. It is not +yet fully understood what changes occur in fallowing to give the +soil the fertility which reduces the water needs of the plant. The +researches of Atkinson in Montana, Stewart and Graves in Utah, and +Jensen in South Dakota make it seem probable that the formation of +nitrates plays an important part in the whole process. If a soil is +of such a nature that neither careful, deep plowing at the right +time nor constant crust cultivation are sufficient to set free an +abundance of plant-food, it may be necessary to apply manures or +commercial fertilizers to the soil. While the question of restoring +soil fertility has not yet come to be a leading one in dry-farming, +yet in view of what has been said in this chapter it is not +impossible that the time will come when the farmers must give +primary attention to soil fertility in addition to the storing and +conservation of soil-moisture. The fertilizing of lands with proper +plant-foods, as shown in the last sections, tends to check +transpiration and makes possible the production of dry matter at the +lowest water-cost. + +The recent practice in practically all dry-farm districts, at least +in the intermountain and far West, to use the header for harvesting +bears directly upon the subject considered in this chapter. The high +stubble which remains contains much valuable plant-food, often +gathered many feet below the surface by the plant roots. When this +stubble is plowed under there is a valuable addition of the +plant-food to the upper soil. Further, as the stubble decays, acid +substances are produced that act upon the soil grains to set free +the plant-food locked up in them. The plowing under of stubble is +therefore of great value to the dry-farmer. The plowing under of any +other organic substance has the same effect. In both cases fertility +is concentrated near the surface, which dissolves in the soil-water +and enables the crop to mature with the Ieast quantity of water. + +The lesson then to be learned from this chapter is, that it is not +aufficient for the dry-farmer to store an abundance of water in the +soil and to prevent that water from evaporating directly from the +soil; but the soil must be kept in such a state of high fertility +that plants are enabled to utilize the stored moisture in the most +economical manner. Water storage, the prevention of evaporation, and +the maintenance of soil fertility go hand in hand in the development +of a successful system of farming without irrigation. + + + + + + +CHAPTER X + +PLOWING AND FALLOWING + + + + + +The soil treatment prescribed in the preceding chapters rests upon +(1) deep and thorough plowing, done preferably in the fall; (2) +thorough cultivation to form a mulch over the surface of the land, +and (3) clean summer fallowing every other year under low rainfall +or every third or fourth year under abundant rainfall. + +Students of dry-farming all agree that thorough cultivation of the +topsoil prevents the evaporation of soil-moisture, but some have +questioned the value of deep and fall plowing and the occasional +clean summer fallow. It is the purpose of this chapter to state the +findings of practical men with reference to the value of plowing and +fallowing in producing large crop yields under dry-farm conditions. + +It will be shown in Chapter XVIII that the first attempts to produce +crops without irrigation under a limited rainfall were made +independently in many diverse places. California, Utah, and the +Columbia Basin, as far as can now be learned, as well as the Great +Plains area, were all independent pioneers in the art of +dry-farming. It is a most significant fact that these diverse +localities, operating under different conditions as to soil and +climate, have developed practically the same system of dry-farming. +In all these places the best dry-farmers practice deep plowing +wherever the subsoil will permit it; fall plowing wherever the +climate will permit it; the sowing of fall grain wherever the +winters will permit it, and the clean summer fallow every other +year, or every third or fourth year. H. W. Campbell, who has been +the leading exponent of dry-farming in the Great Plains area, began +his work without the clean summer fallow as a part of his system, +but has long since adopted it for that section of the country. It is +scarcely to be believed that these practices, developed laboriously +through a long succession of years in widely separated localities, +do not rest upon correct scientific principles. In any case, the +accumulated experience of the dry-farmers in this country confirms +the doctrines of soil tillage for dry-farms laid down in the +preceding chapters. + +At the Dry-Farming Congresses large numbers of practical farmers +assemble for the purpose of exchanging experiences and views. The +reports of the Congress show a great difference of opinion on minor +matters and a wonderful unanimity of opinion on the more fundamental +questions. For instance, deep plowing was recommended by all who +touched upon the subject in their remarks; though one farmer, who +lived in a locality the subsoil of which was very inert, recommended +that the depth of plowing should be increased gradually until the +full depth is reached, to avoid a succession of poor crop years +while the lifeless soil was being vivified. The states of Utah, +Montana, Wyoming, South Dakota, Colorado, Kansas, Nebraska, and the +provinces of Alberta and Saskatchewan of Canada all specifically +declared through one to eight representatives from each state in +favor of deep plowing as a fundamental practice in dry-farming. Fall +plowing, wherever the climatic conditions make it possible, was +similarly advocated by all the speakers. Farmers in certain +localities had found the soil so dry in the fall that plowing was +difficult, but Campbell insisted that even in such places it would +be profitable to use power enough to break up the land before the +winter season set in. Numerous speakers from the states of Utah, +Wyoming, Montana, Nebraska, and a number of the Great Plains states, +as well as from the Chinese Empire, declared themselves as favoring +fall plowing. Scareely a dissenting voice was raised. + +In the discussion of the clean summer fallow as a vital principle of +dry-farming a slight difference of opinion was discovered. Farmers +from some of the localities insisted that the clean summer fallow +every other year was indispensable; others that one in three years +was sufficient; and others one in four years, and a few doubtful the +wisdom of it altogether. However, all the speakers agreed that clean +and thorough cultivation should be practiced faithfully during the +spring, and fall of the fallow year. The appreciation of the fact +that weeds consume precious moisture and fertility seemed to be +general among the dry-farmers from all sections of the country. The +following states, provinces, and countries declared themselves as +being definitely and emphatically in favor of clean summer +fallowing: + +California, Utah, Nevada, Washington, Montana, Idaho, Colorado, New +Mexico, North Dakota, Nebraska, Alberta, Saskatchewan, Russia, +Turkey, the Transvaal, Brazil, and Australia. Each of these many +districts was represented by one to ten or more representatives. The +only state to declare somewhat vigorously against it was from the +Great Plains area, and a warning voice was heard from the United +States Department of Agriculture. The recorded practical experience +of the farmers over the whole of the dry-farm territory of the +United States leads to the conviction that fallowing must he +accepted as a practice which resulted in successful dry-farming. +Further, the experimental leaders in the dry-farm movement, whether +working under private, state, or governmental direction, are, with +very few exceptions, strongly in favor of deep fall plowing and +clean summer fallowing as parts of the dry-farm system. + +The chief reluctance to accept clean summer fallowing as a principle +of dry-farming appears chicfly among students of the Great Plains +area. Even there it is admitted by all that a wheat crop following a +fallow year is larger and better than one following wheat. There +seem, however, to be two serious reasons for objecting to it. First, +a fear that a clean summer fallow, practiced every second, third, or +fourth year, will cause a large diminution of the organic matter in +the soil, resulting finally in complete crop failure; and second, a +belief that a hoed crop, like corn or potatoes, exerts the same +beneficial effect. + +It is undoubtedly true that the thorough tillage involved in +dry-farming exposes to the action of the elements the organic matter +of the soil and thereby favors rapid oxidation. For that reason the +different ways in which organic matter may be supplied regularly to +dry-farms are pointed out in Chapter XIV. It may also be observed +that the header harvesting system employed over a large part of the +dry-farm territory leaves the large header stubble to be plowed +under, and it is probable that under such methods more organic +matter is added to the soil during the year of cropping than is lost +during the year of fallowing. It may, moreover, be observed that +thorough tillage of a crop like corn or potatoes tends to cause a +loss of the organic matter of the soil to a degree nearly as large +as is the case when a fallow field is well cultivated. The thorough +stirring of the soil under an arid or semiarid climate, which is an +essential feature of dry-farming, will always result in a decrease +in organic matter. It matters little whether the soil is fallow or +in crop during the process of cultivation, so far as the result is +concerned. + +A serious matter connected with fallowing in the Great Plains area +is the blowing of the loose well-tilled soil of the fallow fields, +which results from the heavy winds that blow so steadily over a +large part of the western slope of the Mississippi Valley. This is +largely avoided when crops are grown on the land, even when it is +well tilled. + +The theory, recently proposed, that in the Great Plains area, where +the rains come chicfly in summer, the growing of hoed crops may take +the place of the summer fallow, is said to be based on experimental +data not yet published. Careful and conscientious experimenters, as +Chilcott and his co-laborers, indicate in their statements that in +many cases the yields of wheat, after a hoed crop, have been larger +than after a fallow year. The doctrine has, therefore, been rather +widely disseminated that fallowing has no place in the dry-farming +of the Great Plains area and should be replaced by the growing of +hoed crops. Chilcott, who is the chief exponent of this doctrine, +declares, however, that it is only with spring-grown crops and for a +succession of normal years that fallowing may be omitted, and that +fallowing must be resorted to as a safeguard or temporary expedient +to guard against total loss of crop where extreme drouth is +anticipated; that is, where the rainfall falls below the average. He +further explains that continuous grain cropping, even with careful +plowing and spring and fall tillage, is unsuccessful; but holds that +certain rotations of crops, including grain and a hoed crop every +other year, are often more profitable than grain alternating with +clean summer fallow. He further believes that the fallow year every +third or fourth year is sufficient for Great Plains conditions. +Jardine explains that whenever fall grain is grown in the Great +Plains area, the fallow is remarkably helpful, and in fact because +of the dry winters is practically indispensable. + +This latter view is confirmed by the experimental results obtained +by Atkinson and others at the Montana Experiment Stations, which are +conducted under approximately Great Plains conditions. + +It should be mentioned also that in Saskatchewan, in the north end +of the Great Plains area, and which is characteristic, except for a +lower annual temperature, of the whole area, and where dry-farming +has been practiced for a quarter of a century, the clean summer +fallow has come to be an established practice. + +This recent discussion of the place of fallowing in the agriculture +of the Great Plains area illustrates what has been said so often in +this volume about the adapting of principles to local conditions. +Wherever the summer rainfall is sufficient to mature a crop, +fallowing for the purpose of storing moisture in the soil is +unnecessary; the only value of the fallow year under such conditions +would be to set free fertility. In the Great Plains area the +rainfall is somewhat higher than elsewhere in the dry-farm territory +and most of it comes in summer; and the summer precipitation is +probably enough in average years to mature crops, providing soil +conditions are favorable. The main considerations, then, are to keep +the soils open for the reception of water and to maintain the soils +in a sufficiently fertile condition to produce, as explained in +Chapter IX, plants with a minimum amount of water. This is +accomplished very largely by the year of hoed crop, when the soil is +as well stirred as under a clean fallow. + +The dry-farmer must never forget that the critical element in +dry-farming is water and that the annual rainfall will in the very +nature of things vary from year to year, with the result that the +dry year, or the year with a precipitation below the average, is +sure to come. In somewhat wet years the moisture stored in the soil +is of comparatively little consequence, but in a year of drouth it +will be the main dependence of the farmer. Now, whether a crop be +hoed or not, it requires water for its growth, and land which is +continuously cropped even with a variety of crops is likely to be so +largely depleted of its moisture that, when the year of drouth +comes, failure will probably result. + +The precariousness of dry-farming must be done away with. The year +of drouth must be expected every year. Only as certainty of crop +yield is assured will dry-farming rise to a respected place by the +side of other branches of agriculture. To attain such certainty and +respect clean summer fallowing every second, third, or fourth year, +according to the average rainfall, is probably indispensable; and +future investigations, long enough continued, will doubtless confirm +this prediction. Undoubtedly, a rotation of crops, including hoed +crops, will find an important place in dry-farming, but probably not +to the complete exclusion of the clean summer fallow. + +Jethro Tull, two hundred years ago, discovered that thorough tillage +of the soil gave crops that in some cases could not be produced by +the addition of manure, and he came to the erroneous conclusion that +"tillage is manure." In recent days we have learned the value of +tillage in conserving moisture and in enabling plants to reach +maturity with the least amount of water, and we may be tempted to +believe that "tillage is moisture." This, like Tull's statement, is +a fallacy and must be avoided. Tillage can take the place of +moisture only to a limited degree. Water is the essential +consideration in dry-farming, else there would be no dry-farming. + + + + + + +CHAPTER XI + +SOWING AND HARVESTING + + + + + +The careful application of the principles of soil treatment +discussed in the preceding chapters will leave the soil in good +condition for sowing, either in the fall or spring. Nevertheless, +though proper dry-farming insures a first-class seed-bed, the +problem of sowing is one of the most difficult in the successful +production of crops without irrigation. This is chiefly due to the +difficulty of choosing, under somewhat rainless conditions, a time +for sowing that will insure rapid and complete germination and the +establishmcnt of a root system capable of producing good plants. In +some respects fewer definite, reliable principles can be laid down +concerning sowing than any other principle of important application +in the practice of dry-farming. The experience of the last fifteen +years has taught that the occasional failures to which even good +dry-farmers have been subjected have been caused almost wholly by +uncontrollable unfavorable conditions prevailing at the time of +sowing. + +Conditions of germination + +Three conditions determine germination: (1) heat, (2) oxygen, and +(3) water. Unless these three conditions are all favorable, seeds +cannot germinate properly. The first requisite for successful seed +germination is a proper degree of heat. For every kind of seed there +is a temperature below which germination does not occur; another, +above which it does not occur, and another, the best, at which, +providing the other factors are favorable, germination will go on +most rapidly. The following table, constructed by Goodale, shows the +latest, highest, and best germination temperatures for wheat, +barley, and corn. Other seeds germinate approximately within the +same ranges of temperature:-- + + +Germination Temperatures (Degrees Farenheit) + + Lowest Highest Best +Wheat 41 108 84 +Barley 41 100 84 +Corn 49 115 91 + + +Germination occurs within the considerable range between the highest +and lowest temperatures of this table, though the rapidity of +germination decreases as the temperature recedes from the best. This +explains the early spring and late fall germination when the +temperature is comparatively low. If the temperature falls below the +lowest required for germination, dry seeds are not injured, and even +a temperature far below the freezing point of water will not affect +seeds unfavorably if they are not too moist. The warmth of the soil, +essential to germination, cannot well be controlled by the farmer; +and planting must, therefore, be done in seasons when, from past +experience, it is probable that the temperature is and will remain +in the neighborhood of the best degree for germination. More heat is +required to raise the temperature of wet soils; therefore, seeds +will generally germinate more slowly in wet than in dry soils, as is +illustrated in the rapid germination often observed in well-tilled +dry-farm soils. Consequently, it is safer at a low temperature to +sow in dry soils than in wet ones. Dark soils absorb heat more +rapidly than lighter colored ones, and under the same conditions of +temperature germination is therefore more likely to go on rapidly in +dark colored soils. Over the dry-farm territory the soils are +generally light colored, which would tend to delay germination. The +incorporation of organic matter with the soil, which tends to darken +the soil, has a slight though important bearing on germination as +well as on the general fertility of the soil, and should be made an +important dry-farm practice. Meanwhile, the temperature of the soil +depends almost wholly upon the prevailing temperature conditions in +the district and is not to any material degree under the control of +the farmer. + +A sufficient supply of oxygen in the soil is indispensable to +germination. Oxygen, as is well known, forms about one fifth of the +atmosphere and is the active principle in combustion and in tile +changes in the animal body occasioned by respiration. Oxygen should +be present in the soil air in approximately the proportion in which +it is found in the atmosphere. Germination is hindered by a larger +or smaller proportion than is found in the atmosphere. The soil must +be in such a condition that the air can easily enter or leave the +upper soil layer; that is, the soil must be somewhat loose. In order +that the seeds may have access to the necessary oxygen, then, sowing +should not be done in wet or packed soils, nor should the sowing +implements be such as to press the soil too closely around the +seeds. Well-fallowed soil is in an ideal condition for admitting +oxygen. + +If the temperature is right, germination begins by the forcible +absorption of water by the seed from the surrounding soil. The force +of this absorption is very great, ranging from four hundred to five +hundred pounds per square inch, and continues until the seed is +completely saturated. The great vigor with which water is thus +absorbed from the soil explains how seeds are able to secure the +necessary water from the thin water film surrounding the soil +grains. The following table, based upon numerous investigations +conducted in Germany and in Utah, shows the maximum percentages of +water contained by seeds when the absorption is complete. These +quantities are reached only when water is easily accessible:-- + + +Percentage of Water contained by Seeds at Saturation + + German Utah +Rye 58 -- +Wheat 57 52 +Oats 58 43 +Barley 56 44 +Corn 44 57 +Beans 95 88 +Lucern 78 67 + + +Germination itself does not go on freely until this maximum +saturation has been reached. Therefore, if the moisture in the soil +is low, the absorption of water is made difficult and germination is +retarded. This shows itself in a decreased percentage of +germination. The effect upon germination of the percentage of water +in the soil is well shown by some of the Utah experiments, as +follows:-- + + +Effect of Varying Amounts of Water on Percentage of Germination + +Percent water in soil 7.5 10 12.5 15 17.5 20 22.5 25 +Wheat in sandy loam 0.0 98 94 86 82 82 82 6 +Wheat in clay 30 48 84 94 84 82 86 58 +Beans in sandy loam 0 0 20 46 66 18 8 9 +Beans in clay 0 0 6 20 22 32 30 36 +Lucern in Sandy loam 0 18 68 54 54 8 8 9 +Lucern in clay 8 8 54 48 50 32 15 14 + + +In a sandy soil a small percentage of water will cause better +germination than in a clay soil. While different seeds vary in their +power to abstract water from soils, yet it seems that for the +majority of plants, the best percentage of soil-water for +germination purposes is that which is in the neighborhood of the +maximum field capacity of soils for water, as explained in Chapter +VII. Bogdanoff has estimated that the best amount of water in the +soil for germination purposes is about twice the maximum percentage +of hygroscopic water. This would not be far from the field-water +capacity as described in the preceding chapter. + +During the absorption of water, seeds swell considerably, in many +cases from two to three times their normal size. This has the very +desirable effect of crowding the seed walls against the soil +particles and thus, by establishing more points of contact, enabling +the seed to absorb moisture with greater facility. As seeds begin to +absorb water, heat is also produced. In many cases the temperature +surrounding the seeds is increased one degree on the Centigrade +scale by the mere process of water absorption. This favors rapid +germination. Moreover, the fertility of the soil has a direct +influence upon germination. In fertile soils the germination is more +rapid and more complete than in infertile soils. Especially active +in favoring direct germination are the nitrates. When it is recalled +that the constant cultivation and well-kept summer fallow of +dry-farming develop large quantities of nitrates in the soil, it +will be understood that the methods of dry-farming as already +outlined accelerate germination very greatly. + +It scareely need be said that the soil of the seed-bed should be +fine, mellow, and uniform in physical texture so that the seeds can +be planted evenly and in close contact with the soil particles. All +the requisite conditions for germination are best met by the +conditions prevailing in a well-kept summer fallowed soil. + +Time to sow + +In the consideration of the time to sow, the first question to be +disposed of by the dry-farmer is that of fall as against spring +sowing. The small grains occur as fall and spring varieties, and it +is vitally important to determine which season, under dry-farm +conditions, is the best for sowing. + +The advantages of fall sowing are many. As stated, successful +germination is favored by the presence of an abundance of fertility, +especially of nitrates, in the soil. In summer-fallowed land +nitrates are always found in abundance in the fall, ready to +stimulate the seed into rapid germination and the young plants into +vigorous growth. During the late fall and winter months the nitrates +disappear, at least in part, anti from the point of view of +fertility the spring is not so desirable as the fall for +germination. More important, grain sown in the fall under favorable +conditions will establish a good root system which is ready for use +and in action in the early spring as soon as the temperature is +right and long before the farmer can go out on the ground with his +implements. As a result, the crop has the use of the early spring +moisture, which under the conditions of spring sowing is evaporated +into the air. Where the natural precipitation is light and the +amount of water stored in the soil is not large, the gain resulting +from the use of the early spring moisture. often decides the +question in favor of fall sowing. + +The disadvantages of fall sowing are also many. The uncertainty of +the fall rains must first be considered. In ordinary practice, seed +sown in the fall does not germinate until a rain comes, unless +indeed sowing is done immediately after a rain. The fall rains are +uncertain as to quantity. In many cases they are so light that they +suffice only to start germination and not to complete it and give +the plants the proper start. Such incomplete germination frequently +causes the total loss of the crop. Even if the stand of the fall +crop is satisfactory, there is always the danger of winter-killing +to be reckoned with. The real cause of winter-killing is not yet +clearly understood, though it seems that repeated thawing and +freezing, drying winter winds, accompanied by dry cold or protracted +periods of intense cold, destroy the vitality of the seed and young +root system. Continuous but moderate cold is not ordinarily very +injurious. The liability to winter-killing is, therefore, very much +greater wherever the winters are open than in places where the snow +covers the ground the larger part of the winter. It is also to be +kept in mind that some varieties are very resistant to +winter-killing, while others require well-covered winters. Fall +sowing is preferable wherever the bulk of the precipitation comes in +winter and spring and where the winters are covered for some time +with snow and the summers are dry. Under such conditions it is very +important that the crop make use of the moisture stored in the soil +in the early spring. Wherever the precipitation comes largely in +late spring and summer, the arguments in favor of fall sowing are +not so strong, and in such localities spring sowing is often more +desirable than fall sowing. In the Great Plains district, therefore, +spring sowing is usually recommended, though fall-sown crops nearly +always, even there, yield the larger crops. In the intermountain +states, with wet winters and dry summers, fall sowing has almost +wholly replaced spring sowing. In fact, Farrell reports that upon +the Nephi (Utah) substation the average of six years shows about +twenty bushels of wheat from fall-sown seed as against about +thirteen bushels from spring-sown seed. Under the California +climate, with wet winters and a winter temperature high enough for +plant growth, fall sowing is also a general practice. Wherever the +conditions are favorable, fall sowing should be practiced, for it is +in harmony with the best principles of water conservation. Even in +districts where the precipitation comes chiefly in the summer, it +may be found that fall sowing, after all, is preferable. + +The right time to sow in the fall can be fixed only with great +difficulty, for so much depends upon the climatic conditions. In +fact the practice varies in accordance with differences in fall +precipitation and early fall frosts. Where numerous fall rains +maintain the soil in a fairly moist condition and the temperature is +not too low, the problem is comparatively simple. In such districts, +for latitudes represented by the dry-farm sections of the United +States, a good time for fall planting is ordinarily from the first +of September to the middle of October. If sown much earlier in such +districts, the growth is likely to be too rank and subject to +dangerous injury by frosts, and as suggested by Farrell the very +large development of the root system in the fall may cause, the +following summer, a dangerously large growth of foliage; that is, +the crop may run to straw at the expense of the grain. If sown much +later, the chances are that the crop will not possess sufficient +vitality to withstand the cold of late fall and winter. In +localities where the late summer and the early fall are rainless, it +is much more difficult to lay down a definite rule covering the time +of fall sowing. The dry-farmers in such places usually sow at any +convenient time in the hope that an early rain will start the +process of germination and growth. In other cases planting is +delayed until the arrival of the first fall rain. This is an certain +and usually unsatisfactory practice, since it often happens that the +sowing is delayed until too late in the fall for the best results. + +In districts of dry late summer and fall, the greatest danger in +depending upon the fall rains for germination lies in the fact that +the precipitation is often so small that it initiates germination +without being sufficient to complete it. This means that when the +seed is well started in germination, the moisture gives out. When +another slight rain comes a little later, germination is again +started and possibly again stopped. In some seasons this may occur +several times, to the permanent injury of the crop. Dry-farmers try +to provide against this danger by using an unusually large amount of +seed, assuming that a certain amount will fail to come up because of +the repeated partial germinations. A number of investigators have +demonstrated that a seed may start to germinate, then be dried, and +again be started to germinate several times in succession without +wholly destroying the vitality of the seed. + +In these experiments wheat and other seeds were allowed to germinate +and dry seven times in succession. With each partial germination the +percentage of total germination decreased until at the seventh +germination only a few seeds of wheat, barley, and oats retained +their power. This, however, is practically the condition in dry-farm +districts with rainless summers and falls, where fall seeding is +practiced. In such localities little dependence should be placed on +the fall rains and greater reliance placed on a method of soil +treatment that will insure good germination. For this purpose the +summer fallow has been demonstrated to be the most desirable +practice. If the soil has been treated according to the principles +laid down in earlier chapters, the fallowed land will, in the fall, +contain a sufficient amount of moisture to produce complete +germination though no rains may fall. Under such conditions the main +consideration is to plant the seed so deep that it may draw freely +upon the stored soil-moisture. This method makes fall germination +sure in districts where the natural precipitation is not to be +depended upon. + +When sowing is done in the spring, there are few factors to +consider. Whenever the temperature is right and the soil has dried +out sufficiently so that agricultural implements may be used +properly, it is usually safe to begin sowing. The customs which +prevail generally with regard to the time of spring sowing may be +adopted in dry-farm practices also. + +Depth of seeding + +The depth to which seed should be planted in the soil is of +importance in a system of dry-farming. The reserve materials in +seeds are used to produce the first roots and the young plants. No +new nutriment beyond that stored in the soil can be obtained by the +plant until the leaves are above the ground able to gather Carleton +from the atmosphere. The danger of deep planting lies, therefore, in +exhausting the reserve materials of the seeds before the plant has +been able to push its leaves above the ground. Should this occur, +the plant will probably die in the soil. On the other hand, if the +seed is not planted deeply enough, it may happen that the roots +cannot be sent down far enough to connect with the soil-water +reservoir below. Then, the root system will not be strong and deep, +but will have to depend for its development upon the surface water, +which is always a dangerous practice in dry-farming. The rule as to +the depth of seeding is simply: Plant as deeply as is safe. The +depth to which seeds may be safely placed depends upon the nature of +the soil, its fertility, its physical condition, and the water that +it contains. In sandy soils, planting may be deeper than in clay +soils, for it requires less energy for a plant to push roots, stems, +and leaves through the loose sandy soil than through the more +compact clay soil; in a dry soil planting may be deeper than in wet +soils; likewise, deep planting is safer in a loose soil than in one +firmly compacted; finally, where the moist soil is considerable +distance below the surface, deeper planting may be practiced than +when the moist soil is near the surface. Countless experiments have +been conducted on the subject of depth of seeding. In a few cases, +ordinary agricultural seeds planted eight inches deep have come up +and produced satisfactory plants. However, the consensus of opinion +is that from one to three inches are best in humid districts, but +that, everything considered, four inches is the best depth under +dry-farm conditions. Under a low natural precipitation, where the +methods of dry-farming are practiced, it is always safe to plant +deeply, for such a practice will develop and strengthen the root +system, which is one big step toward successful dry-farming. + +Quantity to sow + +Numerous dry-farm failures may be charged wholly to ignorance +concerning the quantity of seed to sow. In no other practice has the +custom of humid countries been followed more religiously by +dry-farmers, and failure has nearly always resulted. The discussions +in this volume have brought out the fact that every plant of +whatever character requires a large amount of water for its growth. +From the first day of its growth to the day of its maturity, large +amounts of water are taken from the soil through the plant and +evaporated into the air through the leaves. When the large +quantities of seed employed in humid countries have been sown on dry +lands, the result has usually been an excellent stand early in the +season, with a crop splendid in appearance up to early summer. .A +luxuriant spring crop reduces, however, the water content of the +soil so greatly that when the heat of the summer arrives, there is +not sufficient water left in the soil to support the final +development and ripening. A thick stand in early spring is no +assurance to the dry-farmer of a good harvest. On the contrary, it +is usually the field with a thin stand in spring that stands up best +through the summer and yields most at the time of harvest. The +quantity of seed sown should vary with the soil conditions: the more +fertile the soil is, the more seed may be used; the more water in +the soil, the more seed may be sown; as the fertility or the water +content diminishes, the amount of seed should likewise be +diminished. Under dry-farm conditions the fertility is good, but the +moisture is low. As a general principle, therefore, light seeding +should be practiced on dry-farms, though it should be sufficient to +yield a crop that will shade the ground well. If the sowing is done +early, in fall or spring, less seed may be used than if the sowing +is late, because the early sowing gives a better chance for root +development, which results, ordinarily, in more vigorous plants that +consume more moisture than the smaller and weaker plants of later +sowing. If the winters are mild and well covered with snow, less +seed may be used than in districts where severe or open winters +cause a certain amount of winter-killing. On a good seed-bed of +fallowed soil less seed may be used than where the soil has not been +carefully tilled and is somewhat rough and lumpy and unfavorable for +complete germination. The yield of any crop is not directly +proportional to the amount sown, unless all factors contributing to +germination are alike. In the case of wheat and other grains, thin +seeding also gives a plant a better chance for stooling, which is +Nature's method of adapting the plant to the prevailing moisture and +fertility conditions. When plants are crowded, stooling cannot occur +to any marked degree, and the crop is rendered helpless in attempts +to adapt itself to surrounding conditions. + +In general the rule may be laid down that a little more than one +half as much seed should be used in dry-farm districts with an +annual rainfall of about fifteen inches than is used in humid +districts. That is, as against the customary five pecks of wheat +used per acre in humid countries about three pecks or even two pecks +should be used on dry-farms. Merrill recommends the seeding of oats +at the rate of about three pecks per acre; of barley, about three +pecks; of rye, two pecks; of alfalfa, six pounds; of corn, two +kernels to the hill, and other crops in the same proportion. No +invariable rule can be laid down for perfect germination. A small +quantity of seed is usually sufficient; but where germination +frequently fails in part, more seed must be used. If the stand is +too thick at the beginning of the growing season, it must be +harrowed out. Naturally, the quantity of seed to be used should be +based on the number of kernels as well as on the weight. For +instance, since the larger the individual wheat kernels the fewer in +a bushel, fewer plants would be produced from a bushel of large than +from a bushel of small seed wheat. The size of the seed in +determining the amount for sowing is often important and should be +determined by some simple method, such as counting the seeds +required to fill a small bottle. + +Method of sowing + +There should really be no need of discussing the method of sowing +were it not that even at this day there are farmers in the dry-farm +district who sow by broadcasting and insist upon the superiority of +this method. The broadcasting of seed has no place in any system of +scientific agriculture, least of all in dry-farming, where success +depends upon the degree with which all conditions are controlled. In +all good dry-farm practice seed should be placed in rows, preferably +by means of one of the numerous forms of drill seeders found upon +the market. The advantages of the drill are almost self-evident. It +permits uniform distribution of the seed, which is indispensable for +success on soils that receive limited rainfall. The seed may be +placed at an even depth, which is very necessary, especially in fall +sowing, where the seed depends for proper germination upon the +moisture already stored in the soil. The deep seeding often +necessary under dry-farm conditions makes the drill indispensable. +Moreover, Hunt has explained that the drill furrows themselves have +definite advantages. During the winter the furrows catch the snow, +and because of the protection thus rendered, the seed is less likely +to be heaved out by repeated freezing and thawing. The drill furrow +also protects to a certain extent against the drying action of winds +and in that way, though the furrows are small, they aid materially +in enabling the young plant to pass through the winter successfully. +The rains of fall and spring are accumulated in the furrows and made +easily accessible to plants. Moreover, many of the drills have +attachments whereby the soil is pressed around the seed and the +topsoil afterwards stirred to prevent evaporation. This permits of a +much more rapid and complete germination. The drill, the advantages +of which were taught two hundred years ago by Jethro Tull, is one of +the most valuable implements of modern agriculture. On dry-farms it +is indispensable. The dry-farmer should make a careful study of the +drills on the market and choose such as comply with the principles +of the successful prosecution of dry-farming. Drill culture is the +only method of sowing that can be permitted if uniform success is +desired. + +The care of the crop + +Excepting the special treatment for soil-moisture conservation, +dry-farm crops should receive the treatment usually given crops +growing under humid conditions. The light rains that frequently fall +in autumn sometimes form a crust on the top of the soil, which +hinders the proper germination and growth of the fall-sown crop. It +may be necessary, therefore, for the farmer to go over the land in +the fall with a disk or more preferably with a corrugated roller. + +Ordinarily, however, after fall sowing there is no further need of +treatment until the following spring. The spring treatment is of +considerably more importance, for when the warmth of spring and +early summer begins to make itself felt, a crust forms over many +kinds of dry-farm soils. This is especially true where the soil is +of the distinctively arid kind and poor in organic matter. Such a +crust should be broken early in order to give the young plants a +chance to develop freely. This may be accomplished, as above stated, +by the use of a disk, corrugated roller, or ordinary smoothing +harrow. + +When the young grain is well under way, it may be found to be too +thick. If so, the crop may be thinned by going over the field with a +good irontooth harrow with the teeth so set as to tear out a portion +of the plants. This treatment may enable the remaining plants to +mature with the limited amount of moisture in the soil. +Paradoxically, if the crop seems to be too thin in the spring, +harrowing may also be of service. In such a case the teeth should be +slanted backwards and the harrowing done simply for the purpose of +stirring the soil without injury to the plant, to conserve the +moisture stored in the soil and to accelerate the formation of +nitrates.--The conserved moisture and added fertility will +strengthen the growth and diminish the water requirements of the +plants, and thus yield a larger crop. The iron-tooth harrow is a +very useful implement on the dry-farm when the crops are young. +After the plants are up so high that the harrow cannot be used on +them no special care need be given them, unless indeed they are +cultivated crops like corn or potatoes which, of course, as +explained in previous chapters, should receive continual +cultivation. + +Harvesting + +The methods of harvesting crops on dry-farms are practically those +for farms in humid districts. The one great exception may be the use +of the header on the grain farms of the dry-farm sections. The +header has now become well-nigh general in its use. Instead of +cutting and binding the grain, as in the old method, the heads are +simply cut off and piled in large stacks which later are threshed. +The high straw which remains is plowed under in the fall and helps +to supply the soil with organic matter. The maintenance of dry-farms +for over a generation without the addition of manures has been made +possible by the organic matter added to the soil in the decay of the +high vigorous straw remaining after the header. In fact, the changes +occurring in the soil in connection with the decaying of the header +stubble appear to have actually increased the available fertility. +Hundreds of Utah dry wheat farms during the last ten or twelve years +have increased in fertility, or at least in productive power, due +undoubtedly to the introduction of the header system of harvesting. +This system of harvesting also makes the practice of fallowing much +more effective, for it helps maintain the organic matter which is +drawn upon by the fallow seasons. The header should be used wherever +practicable. The fear has been expressed that the high header straw +plowed under will make the soil so loose as to render proper sowing +difficult and also, because of the easy circulation of air in the +upper soil layers, cause a large loss of soil-moisture. This fear +has been found to be groundless, for wherever the header straw has +been plowed under; especially in connection with fallowing, the soil +has been benefited. + +Rapidity and economy in harvesting are vital factors in dry-farming, +and new devices are constantly being offered to expedite the work. +Of recent years the combined harvester and thresher has come into +general use. It is a large header combined with an ordinary +threshing machine. The grain is headed and threshed in one operation +and the sacks dropped along the path of the machine. The straw is +scattered over the field where it belongs. + +All in all, the question of sowing, care of crop, and harvesting may +be answered by the methods that have been so well developed in +countries of abundant rainfall, except as new methods may be +required to offset the deficiency in the rainfall which is the +determining condition of dry-farming. + + + + + + +CHAPTER XII + +CROPS FOR DRY-FARMING + + + + + +The work of the dry-farmer is only half done when the soil has been +properly prepared, by deep plowing, cultivation, fallowing, for the +planting of the crop. The choice of the crop, its proper seeding, +and its correct care and harvesting are as important as rational +soil treatment in the successful pursuit of dry-farming. It is true +that in general the kinds of crops ordinarily cultivated in humid +regions are grown also on arid lands, but varieties especially +adapted to the prevailing dry-farm conditions must be used if any +certainty of harvest is desired. Plants possess a marvelous power of +adaptation to environment, and this power becomes stronger as +successive generations of plants are grown under the given +conditions. Thus, plants which have been grown for long periods of +time in countries of abundant rainfall and characteristic humid +climate and soil yield well under such conditions, but usually +suffer and die or at best yield scantily if planted in hot rainless +countries with deep soils. Yet, such plants, if grown year after +year under arid conditions, become accustomed to warmth and dryness +and in time will yield perhaps nearly as well or it may be better in +their new surroundings. The dry-farmer who looks for large harvests +must use every care to secure varieties of crops that through +generations of breeding have become adapted to the conditions +prevailing on his farm. Home-grown seeds, if grown properly, are +therefore of the highest value. In fact, in the districts where +dry-farming has been practiced longest the best yielding varieties +are, with very few exceptions, those that have been grown for many +successive years on the same lands. The comparative newness of the +attempts to produce profitable crops in the present dry-farming +territory and the consequent absence of home-grown seed has rendered +it wise to explore other regions of the world, with similar climatic +conditions, but long inhabited, for suitable crop varieties. The +United States Department of Agriculture has accomplished much good +work in this direction. The breeding of new varieties by scientific +methods is also important, though really valuable results cannot be +expected for many years to come. When results do come from breeding +experiments, they will probably be of the greatest value to the +dry-farmer. Meanwhile, it must be acknowledged that at the present, +our knowledge of dry-farm crops is extremely limited. Every year +will probably bring new additions to the list and great improvements +of the crops and varieties now recommended. The progressive +dry-farmer should therefore keep in close touch with state and +government workers concerning the best varieties to use. + +Moreover, while the various sections of the dry-farming territory +are alike in receiving a small amount of rainfall, they are widely +different in other conditions affecting plant growth, such as soils, +winds, average temperature, and character and severity of the +winters. Until trials have been made in all these varying +localities, it is not safe to make unqualified recommendations of +any crop or crop variety. At the present we can only say that for +dry-farm purposes we must have plants that will produce the maximum +quantity of dry matter with the minimum quantity of water; and that +their periods of growth must be the shortest possible. However, +enough work has been done to establish some general rules for the +guidance of the dry-farmer in the selection of crops. Undoubtedly, +we have as yet had only a glimpse of the vast crop possibilities of +the dry-farming territory in the United States, as well as in other +countries. + +Wheat + +Wheat is the leading dry-farm crop. Every prospect indicates that it +will retain its preëminence. Not only is it the most generally +used cereal, but the world is rapidly learning to depend more and +more upon the dry-farming areas of the world for wheat production. +In the arid and semiarid regions it is now a commonly accepted +doctrine that upon the expensive irrigated lands should be grown +fruits, vegetables, sugar beets, and other intensive crops, while +wheat, corn, and other grains and even much of the forage should be +grown as extensive crops upon the non-irrigated or dry-farm lands. +It is to be hoped that the time is near at hand when it will be a +rarity to see grain grown upon irrigated soil, providing the +climatic conditions permit the raising of more extensive crops. + +In view of the present and future greatness of the wheat crop on +semiarid lands, it is very important to secure the varieties that +will best meet the varying dry-farm conditions. Much has been done +to this end, but more needs to be done. Our knowledge of the best +wheats is still fragmentary. This is even more true of other +dry-farm crops. According to Jardine, the dry-farm wheats grown at +present in the United States may be classificd as follows:-- + + +I. Hard spring wheats: +(a) Common +(b) Durum + +II. Winter wheats: +(a) Hard wheats (Crimean) +(b) Semihard wheats (Intermountain) +(c) Soft wheats (Pactfic) + + +The common varieties of hard _spring wheats _are grown principally +in districts where winter wheats have not as yet been successful; +that is, in the Dakotas, northwestern Nebraska, and other localities +with long winters and periods of alternate thawing and severe +freezing. The superior value of winter wheat has been so clearly +demonstrated that attempts are being made to develop in every +locality winter wheats that can endure the prevailing climatic +conditions. Spring wheats are also grown in a scattering way and in +small quantities over the whole dry-farm territory. The two most +valuable varieties of the common hard spring wheat are Blue Stem and +Red Fife, both well-established varieties of excellent milling +qualities, grown in immense quantities in the Northeastern corner of +the dry-farm territory of the United States and commanding the best +prices on the markets of the world. It is notable that Red Fife +originated in Russia, the country which has given us so many good +dry-farm crops. + +The durum wheats or macaroni wheats, as they are often called, are +also spring wheats which promise to displace all other spring +varieties because of their excellent yields under extreme dry-farm +conditions. These wheats, though known for more than a generation +through occasional shipments from Russia, Algeria, and Chile, were +introduced to the farmers of the United States only in 1900, through +the explorations and enthusiastic advocacy of Carleton of the United +States Department of Agriculture. Since that time they have been +grown in nearly all the dryfarm states and especially in the Great +Plains area. Wherever tried they have yielded well, in some cases as +much as the old established winter varieties. The extreme hardness +of these wheats made it difficult to induce the millers operating +mills fitted for grinding softer wheats to accept them for +flourmaking purposes. This prejudice has, however, gradually +vanished, and to-day the durum wheats are in great demand, +especially for blending with the softer wheats and for the making of +macaroni. Recently the popularity of the durum wheats among the +farmers has been enhanced, owing to the discovery that they are +strongly rust resistant. + +The _winter wheats, _as has been repeatedly suggested in preceding +chapters, are most desirable for dry-farm purposes, wherever they +can be grown, and especially in localities where a fair +precipitation occurs in the winter and spring. The hard winter +wheats are represented mainly by the Crimean group, the chief +members of which are Turkey, Kharkow, and Crimean. These wheats also +originated in Russia and are said to have been brought to the United +States a generation ago by Mennonite colonists. At present these +wheats are grown chiefly in the central and southern parts of the +Great Plains area and in Canada, though they are rapidly spreading +over the intermountain country. These are good milling wheats of +high gluten content and yielding abundantly under dry-farm +conditions. It is quite clear that these wheats will soon displace +the older winter wheats formerly grown on dry-farms. Turkey wheat +promises to become the leading dry-farm wheat. The semisoft winter +wheats are grown chiefly in the intermountain country. They are +represented by a very large number of varieties, all tending toward +softness and starchiness. This may in part be due to climatic, soil, +and irrigation conditions, but is more likely a result of inherent +qualities in the varieties used. They are rapidly being displaced by +hard varieties. + +The group of soft winter wheats includes numerous varieties grown +extensively in the famous wheat districts of California, Oregon, +Washington, and northern Idaho. The main varieties are Red Russian +and Palouse Blue Stem, in Washington and Idaho, Red Chaff and Foise +in Oregon, and Defiance, Little Club, Sonora, and White Australian +in California. These are all soft, white, and rather poor in gluten. +It is believed that under given climatic, soil, and cultural +conditions, all wheat varieties will approach one type, distinctive +of the conditions in question, and that the California wheat type is +a result of prevailing unchangeable conditions. More researeh is +needed, however, before definite principles can be laid down +concerning the formation of distinctive wheat types in the various +dry-farm sections. Under any condition, a change of seed, keeping +improvement always in view, should be baneficial. + +Jardine has reminded the dry-farmers of the United States that +before the production of wheat on the dry-farms can reach its full +possibilities under any acreage, sufficient quantities must be grown +of a few varieties to affect the large markets. This is especially +important in the intermountain country where no uniformity exists, +but the warning should be heeded also by the Pacific coast and Great +Plains wheat areas. As soon as the best varieties are found they +should displace the miscellaneous collection of wheat varieties now +grown. The individual farmer can be a law unto himself no more in +wheat growing than in fruit growing, if he desires to reap the +largest reward of his efforts. Only by uniformity of kind and +quality and large production will any one locality impress itself +upon the markets and create a demand. The changes now in progress by +the dry-farmers of the United States indicate that this lesson has +been taken to heart. The principle is equally important for all +countries where dry-farming is practiced. + +Other small grains + +_Oats _is undoubtedly a coming dry-farm crop. Several varieties have +been found which yield well on lands that receive an average annual +rainfall of less than fifteen inches. Others will no doubt be +discovered or developed as special attention is given to dry-farm +oats. Oats occurs as spring and winter varieties, but only one +winter variety has as yet found place in the list of dry-farm crops. +The leading; spring varieties of oats are the Sixty-Day, Kherson, +Burt, and Swedish Select. The one winter variety, which is grown +chiefly in Utah, is the Boswell, a black variety originally brought +from England about 1901. + +_Barley, _like the other common grains, occurs in varieties that +grow well on dry-farms. In comparison with wheat very little seareh +has been made for dry-farm barleys, and, naturally, the list of +tested varieties is very small. Like wheat and oats, barley occurs +in spring and winter varieties, but as in the case of oats only one +winter variety has as yet found its way into the approved list of +dry-farm crops. The best dry-farm spring barleys are those belonging +to the beardless and hull-less types, though the more common +varieties also yield well, especially the six-rowed beardless +barley. The winter variety is the Tennessee Winter, which is already +well distributed over the Great Plains district. + +_Rye _is one of the surest dry-farm crops. It yields good crops of +straw and grain, both of which are valuable stock foods. In fact, +the great power of rye to survive and grow luxuriantly under the +most trying dry-farm conditions is the chief objection to it. Once +started, it is hard to eradicate. Properly cultivated and used +either as a stock feed or as green manure, it is very valuable. Rye +occurs as both spring and winter varieties. The winter varieties are +usually most satisfactory. + +Carleton has recommended _emmer _as a crop peculiarly adapted to +semiarid conditions. Emmer is a species of wheat to the berries of +which the chaff adheres very closely. It is highly prized as a stock +feed. In Russia and Germany it is grown in very large quantities. It +is especially adapted to arid and semiarid conditions, but will +probably thrive best where the winters are dry and summers wet. It +exists as spring and winter varieties. is with the other small +grains, the success of emmer will depend largely upon the +satisfactory development of winter varieties. + +Corn + +Of all crops yet tried on dry-farms, corn is perhaps the most +uniformly successful under extreme dry conditions. If the soil +treatment and planting have been right, the failures that have been +reported may invariably be traced to the use of seed which had not +been acclimated. The American Indians grow corn which is excellent +for dry-farm purposes; many of the western farmers have likewise +produced strains that use the minimum of moisture, and, moreover, +corn brought from humid sections adapts itself to arid conditions in +a very few years. Escobar reports a native corn grown in Mexico with +low stalks and small ears that well endures desert conditions. In +extremely dry years corn does not always produce a profitable crop +of seed, but the crop as a whole, for forage purposes, seldom fails +to pay expenses and leave a margin for profit. In wetter years there +is a corresponding increase of the corn crop. The dryfarming +territory does not yet realize the value of corn as a dry-farm crop. +The known facts concerning corn make it safe to predict, however, +that its dry farm acreage will increase rapidly, and that in time it +will crowd the wheat crop for preëminence. + +Sorghums + +Among dry-farm crops not popularly known are the sorghums, which +promise to become excellent yielders under arid conditions. The +sorghums are supposed to have come grown the tropical sections of +the globe, but they are now scattered over the earth in all climes. +The sorghums have been known in the United States for over half a +century, but it was only when dry-farming began to develop so +tremendously that the drouth-resisting power of the sorghums was +recalled. According to Ball, the sorghums fall into the following +classes:-- + + +THE SORGHUMS + +1. Broom corns +2. Sorgas or sweet sorghums +3. Kafirs +4. Durras + + +The broom corns are grown only for their brush, and are not +considered in dry-farming; the sorgas for forage and sirups, and are +especially adapted for irrigation or humid conditions, though they +are said to endure dry-farm conditions better than corn. The Kafirs +are dry-farm crops and are grown for grain and forage. This group +includes Red Kafir, White Kafir, Black-hulled White Kafir, and White +Milo, all of which are valuable for dry-farming. The Durras are +grown almost exclusively for seed and include Jerusalem corn, Brown +Durra, and Milo. The work of Ball has made Milo one of the most +important dry-farm crops. As improved, the crop is from four to four +and a half feet high, with mostly erect heads, carrying a large +quantity of seeds. Milo is already a staple crop in parts of Texas, +Oklahoma, Kansas, and New Mexico. It has further been shown to be +adapted to conditions in the Dakotas, Nebraska, Colorado, Arizona, +Utah, and Idaho. It will probably be found, in some varietal form, +valuable over the whole dry-farm territory where the altitude is not +too high and the average temperature not too low. + +It has yielded an average of forty bushels of seed to the acre. + +Lucern or alfalfa + +Next to human intelligence and industry, alfalfa has probably been +the chief factor in the development of the irrigated West. It has +made possible a rational system of agriculture, with the live-stock +industry and the maintenance of soil fertility as the central +considerations. Alfalfa is now being recognized as a desirable crop +in humid as well as in irrigated sections, and it is probable that +alfalfa will soon become the chief hay crop of the United States. +Originally, lucern came from the hot dry countries of Asia, where it +supplied feed to the animals of the first historical peoples. +Moreover, its long; tap roots, penetrating sometimes forty or fifty +feet into the ground, suggest that lucern may make ready use of +deeply stored soil-moisture. On these considerations, alone, lucern +should prove itself a crop well suited for dry-farming. In fact, it +has been demonstrated that where conditions are favorable, lucern +may be made to yield profitable crops under a rainfall between +twelve and fifteen inches. Alfalfa prefers calcareous loamy soils; +sandy and heavy clay soils are not so well adapted for successful +alfalfa production. Under dry-farm conditions the utmost care must +be used to prevent too thick seeding. The vast majority of alfalfa +failures on dry-farms have resulted from an insufficient supply of +moisture for the thickly planted crop. The alfalfa field does not +attain its maturity until after the second year, and a crop which +looks just right the second year will probably be much too thick the +third and fourth years. From four to six pounds of seed per acre are +usually ample. Another main cause of failure is the common idea that +the lucern field needs little or no cultivation, when, in fact, the +alfalfa field should receive as careful soil treatment as the wheat +field. Heavy, thorough disking in spring or fall, or both, is +advisable, for it leaves the topsoil in a condition to prevent +evaporation and admit air. In Asiatic and North African countries, +lucern is frequently cultivated between rows throughout the hot +season. This has been tried by Brand in this country and with very +good results. Since the crop should always be sown with a drill, it +is comparatively easy to regulate the distance between the rows so +that cultivating implements may be used. If thin seeding and +thorough soil stirring are practiced, lucern usually grows well, and +with such treatment should become one of the great dry-farm crops. +The yield of hay is not large, but sufficient to leave a comfortable +margin of profit. Many farmers find it more profitable to grow +dry-farm lucern for seed. In good years from fifty to one hundred +and fifty dollars may be taken from an acre of lucern seed. However, +at the present, the principles of lucern seed production are not +well established, and the seed crop is uncertain. + +Alfalfa is a leguminous crop and gathers nitrogen from the air. It +is therefore a good fertilizer. The question of soil fertility will +become more important with the passing of the years, and the value +of lucern as a land improver will then be more evident than it is +to-day. + +Other leguminous crops + +The group of leguminous or pod-bearing crops is of great importance; +first, because it is rich in nitrogenous substances which are +valuable animal foods, and, secondly, because it has the power of +gathering nitrogen from the air, which can be used for maintaining +the fertility of the soil. Dry-farming will not be a wholly safe +practice of agriculture until suitable leguminous crops are found +and made part of the crop system. It is notable that over the whole +of the dry-farm territory of this and other countries wild +leguminous plants flourish. That is, nitrogen-gathering plants are +at work on the deserts. The farmer upsets this natural order of +things by cropping the land with wheat and wheat only, so long as +the land will produce profitably. The leguminous plants native to +dry-farm areas have not as yet been subjected to extensive economic +study, and in truth very little is known concerning leguminous +plants adapted to dry-farming. + +In California, Colorado, and other dry-farm states the field pea has +been grown with great profit. Indeed it has been found much more +profitable than wheat production. The field bean, likewise, has been +grown successfully under dry-farm conditions, under a great variety +of climates. In Mexico and other southern climates, the native +population produce large quantities of beans upon their dry lands. + +Shaw suggests that sanfoin, long famous for its service to European +agriculture, may be found to be a profitable dry-farm crop, and that +sand vetch promises to become an excellent dry-farm crop. It is very +likely, however, that many of the leguminous crops which have been +developed under conditions of abundant rainfall will be valueless on +dry-farm lands. Every year will furnish new and more complete +information on this subject. Leguminous plants will surely become +important members of the association of dry-farm crops. + +Trees and shrubs + +So far, trees cannot be said to be dry-farm crops, though facts are +on record that indicate that by the application of correct dry-farm +principles trees may be made to grow and yield profitably on +dry-farm lands. Of course, it is a well-known fact that native trees +of various kinds are occasionally found growing on the deserts, +where the rainfall is very light and the soil has been given no +care. Examples of such vegetation are the native cedars found +throughout the Great Basin region and the mesquite tree in Arizona +and the Southwest. Few farmers in the arid region have as yet +undertaken tree culture without the aid of irrigation. + +At least one peach orchard is known in Utah which grows under a +rainfall of about fifteen inches without irrigation and produces +regularly a small crop of most delicious fruit. Parsons describes +his Colorado dry-farm orchard in which, under a rainfall of almost +fourteen inches, he grows, with great profit, cherries, plums, and +apples. A number of prospering young orchards are growing without +irrigation in the Great Plains area. Mason discovered a few years +ago two olive orchards in Arizona and the Colorado desert which, +planted about fourteen years previously, were thriving under an +annual rainfall of eight and a half and four and a half inches, +respectively. These olive orchards had been set out under canals +which later failed. Such attested facts lead to the thought that +trees may yet take their place as dry-farm crops. This hope is +strengthened when it is recalled that the great nations of +antiquity, living in countries of low rainfall, grew profitably and +without irrigation many valuable trees, some of which are still +cultivated in those countries. The olive industry, for example, is +even now being successfully developed by modern methods in Asiatic +and African sections, where the average annual rainfall is under ten +inches. Since 1881, under French management, the dry-farm olive +trees around Tunis have increased from 45,000 to 400,000 +individuals. Mason and also Aaronsohn suggest as trees that do well +in the arid parts of the old world the so-called "Chinese date" or +JuJube tree, the sycamore fig, and the Carob tree, which yields the +"St. John's Bread" so dear to childhood. + +Of this last tree, Aaronsolm says that twenty trees to the acre, +under a rainfall of twelve inches, will produce 8000 pounds of fruit +containing 40 per cent of sugar and 7 to 8 per cent of protein. This +surpasses the best harvest of alfalfa. Kearnley, who has made a +special study of dry-land olive culture in northern Africa, states +that in his belief a large variety of fruit trees may be found which +will do well under arid and semiarid conditions, and may even yield +more profit than the grains. + +It is also said that many shade and ornamental and other useful +plants can be grown on dry-farms; as, for instance, locust, elm, +black walnut, silverpoplar, catalpa, live oak, black oak, yellow +pine, red spruce, Douglas fir, and cedar. + +The secret of success in tree growing on dry-farms seems to lie, +first, in planting a few trees per acre,--the distance apart should +be twice the ordinary distance,--and, secondly, in applying +vigorously and unceasingly the established principles of soil +cultivation. In a soil stored deeply with moisture and properly +cultivated, most plants will grow. If the soil has not been +carefully fallowed before planting, it may be necessary to water the +young trees slightly during the first two seasons. + +Small fruits have been tried on many farms with great success. +Plums, currants, and gooseberries have all been successful. Grapes +grow and yield well in many dry-farm districts, especially along the +warm foothills of the Great Basin. Tree growing on dry-farm lands is +not yet well established and, therefore, should be undertaken with +great care. Varieties accustomed to the climatic environment should +be chosen, and the principles outlined in the preceding pages should +be carefully used. + +Potatoes + +In recent years, potatoes have become one of the best dry-farm +crops. Almost wherever tried on lands under a rainfall of twelve +inches or more potatoes have given comparatively large yields. +To-day, the growing of dry-farm potatoes is becoming an important +industry. The principles of light seeding and thorough cultivation +are indispensable for success. Potatoes are well adapted for use in +rotations, where summer fallowing is not thought desirable. +Macdonald enumerates the following as the best varieties at present +used on dry-farms: Ohio, Mammoth, Pearl, Rural New Yorker, and +Burbank. + +Miscellaneous + +A further list of dry-farm crops would include representatives of +nearly all economic plants, most of them tried in small quantity in +various localities. Sugar beets, vegetables, bulbous plants, etc., +have all been grown without irrigation under dry-farm conditions. +Some of these will no doubt be found to be profitable and will then +be brought into the commercial scheme of dry-farming. + +Meanwhile, the crop problems of dry-farming demand that much careful +work be done in the immediate future by the agencies having such +work in charge. The best varieties of crops already in profitable +use need to be determined. More new plants from all parts of the +world need to be brought to this new dry-farm territory and tried +out. Many of the native plants need examination with a view to their +economic use. For instance, the sego lily bulbs, upon which the Utah +pioneers subsisted for several seasons of famine, may possibly be +made a cultivated crop. Finally, it remains to be said that it is +doubtful wisdom to attempt to grow the more intensive crops on +dry-farms. Irrigation and dry-farming will always go together. They +are supplementary systems of agriculture in arid and semiarid +regions. On the irrigated lands should be grown the crops that +require much labor per acre and that in return yield largely per +acre. New crops and varieties should besought for the irrigated +farms. On the dry-farms should be grown the crops that can be +handled in a large way and at a small cost per acre, and that yield +only moderate acre returns. By such cooperation between irrigation +and dry-farming will the regions of the world with a scanty rainfall +become the healthiest, wealthiest, happiest, and most populous on +earth. + + + + + + +CHAPTER XIII + +THE COMPOSITION OF DRY-FARM CROPS + + + + + +The acre-yields of crops on dry-farms, even under the most favorable +methods of culture, are likely to be much smaller than in humid +sections with fertile soils. The necessity for frequent fallowing or +resting periods over a large portion of the dry-farm territory +further decreases the average annual yield. It does not follow from +this condition that dry-farming is less profitable than humid-or +irrigation-farming, for it has been fully demonstrated that the +profit on the investment is as high under proper dry-farming as +under any other similar generally adopted system of farming in any +part of the world. Yet the practice of dry-farming would appear to +be, and indeed would be, much more desirable could the crop yield be +increased. The discovery of any condition which will offset the +small annual yields is, therefore, of the highest importance to the +advancement of dry-farming. The recognition of the superior quality +of practically all crops grown without irrigation under a limited +rainfall has done much to stimulate faith in the great +profitableness of dry-farming. As the varying nature of the +materials used by man for food, clothing, and shelter has become +more clearly understood, more attention has been given to the +valuation of commercial products on the basis of quality as well as +of quantity. Sugar beets, for instance, are bought by the sugar +factories under a guarantee of a minimum sugar content; and many +factories of Europe vary the price paid according to the sugar +contained by the beets. The millers, especially in certain parts of +the country where wheat has deteriorated, distinguish carefully +between the flour-producing qualities of wheats from various +sections and fix the price accordingly. Even in the household, +information concerning the real nutritive value of various foods is +being sought eagerly, and foods let down to possess the highest +value in the maintenance of life are displacing, even at a higher +cost, the inferior products. The quality valuation is, in fact, +being extended as rapidly as the growth of knowledge will permit to +the chief food materials of commerce. As this practice becomes fixed +the dry-farmer will be able to command the best market prices for +his products, for it is undoubtedly true that from the point of view +of quality, dry-farm food products may be placed safely in +competition with any farm products on the markets of the world. + +Proportion of plant parts + +It need hardly be said, after the discussions in the preceding +chapters, that the nature of plant growth is deeply modified by the +arid conditions prevailing in dry-farming. This shows itself first +in the proportion of the various plant parts, such as roots, stems, +leaves, and seeds. The root systems of dry-farm crops are generally +greatly developed, and it is a common observation that in adverse +seasons the plants that possess the largest and most vigorous roots +endure best the drouth and burning heat. The first function of the +leaves is to gather materials for the building and strengthening of +the roots, and only after this has been done do the stems lengthen +and the leaves thicken. Usually, the short season is largely gone +before the stem and leaf growth begins, and, consequently, a +somewhat dwarfed appearance is characteristic of dry-farm crops. The +size of sugar beets, potato tubers, and such underground parts +depends upon the available water and food supply when the plant has +established a satisfactory root and leaf system. If the water and +food are scarce, a thin beet results; if abundant, a well-filled +beet may result. + +Dry-farming is characterized by a somewhat short season. Even if +good growing weather prevails, the decrease of water in the soil has +the effect of hastening maturity. The formation of flowers and seed +begins, therefore, earlier and is completed more quickly under arid +than under humid conditions. Moreover, and resulting probably from +the greater abundance of materials stored in the root system, the +proportion of heads to leaves and stems is highest in dry-farm +crops. In fact, it is a general law that the proportion of heads to +straw in grain crops increases as the water supply decreases. This +is shown very well even under humid or irrigation conditions when +different seasons or different applications of irrigation water are +compared. For instance, Hall quotes from the Rothamsted experiments +to the effect that in 1879, which was a wet year (41 inches), the +wheat crop yielded 38 pounds of grain for every 100 pounds of straw; +whereas, in 1893, which was a dry year (23 inches), the wheat crop +yielded 95 pounds of grain to every 100 pounds of straw. The Utah +station likewise has established the same law under arid conditions. +In one series of experiments it was shown as an average of three +years' trial that a field which had received 22.5 inches of +irrigation water produced a wheat crop that gave 67 pounds of grain +to every 100 pounds of straw; while another field which received +only 7.5 inches of irrigation water produced a crop that gave 100 +pounds of grain for every 100 pounds of straw. Since wheat is grown +essentially for the grain, such a variation is of tremendous +importance. The amount of available water affects every part of the +plant. Thus, as an illustration, Carleton states that the per cent +of meat in oats grown in Wisconsin under humid conditions was 67.24, +while in North Dakota, Kansas, and Montana, under arid and semiarid +conditions, it was 71.51. Similar variations of plant parts may be +observed as a direct result of varying the amount of available +water. In general then, it may be said that the roots of dry-farm +crops are well developed; the parts above ground somewhat dwarfed; +the proportion of seed to straw high, and the proportion of meat or +nutritive materials in the plant parts likewise high. + +The water in dry-farm crops + +One of the constant constituents of all plants and plant parts is +water. Hay, flour, and starch contain comparatively large quantities +of water, which can be removed only by heat. The water in green +plants is often very large. In young lucern, for instance, it +reaches 85 per cent, and in young peas nearly 90 per cent, or more +than is found in good cow's milk. The water so held by plants has no +nutritive value above ordinary water. It is, therefore, profitable +for the consumer to buy dry foods. In this particular, again, +dry-farm crops have a distinct advantage: During growth there is not +perhaps a great difference in the water content of plants, due to +climatic differences, but after harvest the drying-out process goes +on much more completely in dry-farm than in humid districts. Hay, +cured in humid regions, often contains from 12 to 20 per cent of +water; in arid climates it contains as little as 5 per cent and +seldom more than 12 per cent. The drier hay is naturally more +valuable pound for pound than the moister hay, and a difference in +price, based upon the difference in water content, is already being +felt in certain sections of the West. + +The moisture content of dry-farm wheat, the chief dry-farm crop, is +even more important. According to Wiley the average water content of +wheat for the United States is 10.62 per cent, ranging from 15 to 7 +per cent. Stewart and Greaves examined a large number of wheats +grown on the dry-farms of Utah and found that the average per cent +of water in the common bread varieties was 8.46 and in the durum +varieties 8.89. This means that the Utah dry-farm wheats transported +to ordinary humid conditions would take up enough water from the air +to increase their weight one fortieth, or 2.2 per cent, before they +reached the average water content of American wheats. In other +words, 1,000,000 bushels of Utah dry-farm wheat contain as much +nutritive matter as 1,025,000 bushels of wheat grown and kept under +humid conditions. This difference should be and now is recognized in +the prices paid. In fact, shrewd dealers, acquainted with the +dryness of dry-farm wheat, have for some years bought wheat from the +dry-farms at a slightly increased price, and trusted to the increase +in weight due to water absorption in more humid climates for their +profits. The time should be near at hand when grains and similar +products should be purchased upon the basis of a moisture test. + +While it is undoubtedly true that dry-farm crops are naturally drier +than those of humid countries, yet it must also be kept in mind that +the driest dry-farm crops are always obtained where the summers are +hot and rainless. In sections where the precipitation comes chiefly +in the spring and summer the difference would not be so great. +Therefore, the crops raised on the Great Plains would not be so dry +as those raised in California or in the Great Basin. Yet, wherever +the annual rainfall is so small as to establish dry-farm conditions, +whether it comes in the winter or summer, the cured crops are drier +than those produced under conditions of a much higher rainfall, and +dry farmers should insist that, so far as possible in the future, +sales be based on dry matter. + +The nutritive substances in crops + +The dry matter of all plants and plant parts consists of three very +distinct classes of substances: First, ash or the mineral +constituents. Ash is used by the body in building bones and in +supplying the blood with compounds essential to the various life +processes. Second, protein or the substances containing the element +nitrogen. Protein is used by the body in making blood, muscle, +tendons, hair, and nails, and under certain conditions it is burned +within the body for the production of heat. Protein is perhaps the +most important food constituent. Third, non-nitrogenous substances, +including fats, woody fiber, and nitrogen-free extract, a name given +to the group of sugars, starehes, and related substances. These +substances are used by the body in the production of fat, and are +also burned for the production of heat. Of these valuable food +constituents protein is probably the most important, first, because +it forms the most important tissues of the body and, secondly, +because it is less abundant than the fats, starches, and sugars. +Indeed, plants rich in protein nearly always command the highest +prices. + +The composition of any class of plants varies considerably in +different localities and in different seasons. This may be due to +the nature of the soil, or to the fertilizer applied, though +variations in plant composition resulting from soil conditions are +comparatively small. The greater variations are almost wholly the +result of varying climate and water supply. As far as it is now +known the strongest single factor in changing the composition of +plants is the amount of water available to the growing plant. + +Variations due to varying water supply + +The Utah station has conducted numerous experiments upon the effect +of water upon plant composition. The method in every case has been +to apply different amounts of water throughout the growing season on +contiguous plats of uniform land. [Lengthy table deleated from this +edition.] Even a casual study of . . . [the results show] that the +quantity of water used influenced the composition of the plant +parts. The ash and the fiber do not appear to be greatly influenced, +but the other constituents vary with considerable regularity with +the variations in the amount of irrigation water. The protein shows +the greatest variation. As the irrigation water is increased, the +percentage of protein decreases. In the case of wheat the variation +was over 9 per cent. The percentage of fat and nitrogen-free +extract, on the other hand, becomes larger as the water increases. +That is, crops grown with little water, as in dry-farming, are rich +in the important flesh-and blood-forming substance protein, and +comparatively poor in fat, sugar, stareh, and other of the more +abundant heat and fat-producing substances. This difference is of +tremendous importance in placing dry-farming products on the food +markets of the world. Not only seeds, tubers, and roots show this +variation, but the stems and leaves of plants grown with little +water are found to contain a higher percentage of protein than those +grown in more humid climates. + +The direct effect of water upon the composition of plants has been +observed by many students. For instance, Mayer, working in Holland, +found that, in a soil containing throughout the season 10 per cent +of water, oats was produced containing 10.6 per cent of protein; in +soil containing 30 per cent of water, the protein percentage was +only 5.6 per cent, and in soil containing 70 per cent of water, it +was only 5.2 per cent. Carleton, in a study of analyses of the same +varieties of wheat grown in humid and semi-arid districts of the +United States, found that the percentage of protein in wheat from +the semiarid area was 14.4 per cent as against 11.94 per cent in the +wheat from the humid area. The average protein content of the wheat +of the United States is a little more than 12 per cent; Stewart and +Greaves found an average of 16.76 per cent of protein in Utah +dry-farm wheats of the common bread varieties and 17.14 per cent in +the durum varieties. The experiments conducted at Rothamsted, +England, as given by Hall, confirm these results. For example, +during 1893, a very dry year, barley kernels contained 12.99 per +cent of protein, while in 1894, a wet, though free-growing year, the +barley contained only 9.81 per cent of protein. Quotations might be +multiplied confirming the principle that crops grown with little +water contain much protein and little heat-and fat-producing +substances. + +Climate and composition + +The general climate, especially as regards the length of the growing +season and naturally including the water supply, has a strong effect +upon the composition of plants. Carleton observed that the same +varieties of wheat grown at Nephi, Utah, contained 16.61 per cent +protein; at Amarillo, Texas, 15.25 per cent; and at McPherson, +Kansas, a humid station, 13.04 per cent. This variation is +undoubtedly due in part to the varying annual precipitation but, +also, and in large part, to the varying general climatic conditions +at the three stations. + +An extremely interesting and important experiment, showing the +effect of locality upon the composition of wheat kernels, is +reported by LeClerc and Leavitt. Wheat grown in 1905 in Kansas was +planted in 1906 in Kansas, California, and Texas In 1907 samples of +the seeds grown at these three points were planted side by side at +each of the three states All the crops from the three localities +were analyzed separately each year. + +The results are striking and convincing. The original seed grown in +Kansas in 1905 contained 16.22 per cent of protein. The 1906 crop +grown from this seed in Kansas contained 19.13 per cent protein; in +California, 10.38 percent; and in Texas, 12.18 percent. In 1907 the +crop harvested in Kansas from the 1906 seed from these widely +separated places and of very different composition contained +uniformly somewhat more than 22 per cent of protein; harvested in +California, somewhat more than 11 per cent; and harvested in Texas, +about 18 per cent. In short, the composition of wheat kernels is +independent of the composition of the seed or the nature of the +soil, but depends primarily upon the prevailing climatic conditions, +including the water supply. The weight of the wheat per bushel, that +is, the average size and weight of the wheat kernel, and also the +hardness or flinty character of the kernels, were strongly affected +by the varying climatic conditions. It is generally true that +dry-farm grain weighs more per bushel than grain grown under humid +conditions; hardness usually accompanies a high protein content and +is therefore characteristic of dry-farm wheat. These notable lessons +teach the futility of bringing in new seed from far distant places +in the hope that better and larger crops may be secured. The +conditions under which growth occurs determine chiefly the nature of +the crop. It is a common experience in the West that farmers who do +not understand this principle send to the Middle West for seed corn, +with the result that great crops of stalks and leaves with no ears +are obtained. The only safe rule for the dry-farmer to follow is to +use seed which has been grown for many years under dry-farm +conditions. + +A reason for variation in composition + +It is possible to suggest a reason for the high protein content of +dry-farm crops. It is well known that all plants secure most of +their nitrogen early in the growing period. From the nitrogen, +protein is formed, and all young plants are, therefore, very rich in +protein. As the plant becomes older, little more protein is added, +but more and more carbon is taken from the air to form the fats, +starches, sugars, and other non-nitrogenous substances. +Consequently, the proportion or percentage of protein becomes +smaller as the plant becomes older. The impelling purpose of the +plant is to produce seed. Whenever the water supply begins to give +out, or the season shortens in any other way, the plant immediately +begins to ripen. Now, the essential effect of dry-farm conditions is +to shorten the season; the comparatively young plants, yet rich in +protein, begin to produce seed; and at harvest, seed, and leaves, +and stalks are rich in the flesh-and blood-forming element of +plants. In more humid countries plants delay the time of seed +production and thus enable the plants to store up more carbon and +thus reduce the percent of protein. The short growing season, +induced by the shortness of water, is undoubtedly the main reason +for the higher protein content and consequently higher nutritive +value of all dry-farm crops. + +Nutritive value of dry-farm hay, straw, and flour + +All the parts of dry-farm crops are highly nutritious. This needs to +be more clearly understood by the dry-farmers. Dry-farm hay, for +instance, because of its high protein content, may be fed with crops +not so rich in this element, thereby making a larger profit for the +farmer. Dry-farm straw often has the feeding value of good hay, as +has been demonstrated by analyses and by feeding tests conducted in +times of hay scarcity. Especially is the header straw of high +feeding value, for it represents the upper and more nutritious ends +of the stalks. Dry-farm straw, therefore, should be carefully kept +and fed to animals instead of being scattered over the ground or +even burned as is too often the case. Only few feeding experiments +having in view the relative feeding value of dry-farm crops have as +yet been made, but the few on record agree in showing the superior +value of dry-farm crops, whether fed singly or in combination. + +The differences in the chemical composition of plants and plant +products induced by differences in the water-supply and climatic +environment appear in the manufactured products, such as flour, +bran, and shorts. Flour made from Fife wheat grown on the dry-farms +of Utah contained practically 16 per cent of protein, while flour +made from Fife wheat grown in Lorraine and the Middle West is +reported by the Maine Station as containing from 13.03 to 13.75 per +cent of protein. Flour made from Blue Stem wheat grown on the Utah +dry-farms contained 15.52 per cent of protein; from the same variety +grown in Maine and in the Middle West 11.69 and 11.51 per cent of +protein respectively. The moist and dry gluten, the gliadin and the +glutenin, all of which make possible the best and most nourishing +kinds of bread, are present in largest quantity and best proportion +in flours made from wheats grown under typical dry-farm conditions. +The by-products of the milling process, likewise, are rich in +nutritive elements. + +Future Needs + +It has already been pointed out that there is a growing tendency to +purchase food materials on the basis of composition. New discoveries +in the domains of plant composition and animal nutrition and the +improved methods of rapid and accurate valuation will accelerate +this tendency. Even now, manufacturers of food products print on +cartons and in advertising matter quality reasons for the superior +food values of certain articles. At least one firm produces two +parallel sets of its manufactured foods, one for the man who does +hard physical labor, and the other for the brain worker. Quality, as +related to the needs of the body, whether of beast or man, is +rapidly becoming the first question in judging any food material. +The present era of high prices makes this matter even more +important. + +In view of this condition and tendency, the fact that dry-farm +products are unusually rich in the most valuable nutritive materials +is of tremendous importance to the development of dry-farming. The +small average yields of dry-farm crops do not look so small when it +is known that they command higher prices per pound in competition +with the larger crops of more humid climates. More elaborate +investigations should be undertaken to determine the quality of +crops grown in different dry-farm districts. As far as possible each +section, great or small, should confine itself to the growing of a +variety of each crop yielding well and possessing the highest +nutritive value. In that manner each section of the great dry-farm +territory would soon come to stand for some dependable special +quality that would compel a first-class market. Further, the +superior feeding value of dry-farm products should be thoroughly +advertised among the consumers in order to create a demand on the +markets for a quality valuation. A few years of such systematic +honest work would do much to improve the financial basis of +dry-farming. + +CHAPER XIV + +MAINTAINING THE SOIL FERTILITY + +All plants when carefully burned leave a portion of ash, ranging +widely in quantity, averaging about 5 per cent, and often exceeding +10 per cent of the dry weight of the plant. This plant ash +represents inorganic substances taken from the soil by the roots. In +addition, the nitrogen of plants, averaging about 2 per cent and +often amounting to 4 per cent, which, in burning, passes off in +gaseous form, is also usually taken from the soil by the plant +roots. A comparatively large quantity of the plant is, therefore, +drawn directly from the soil. Among the ash ingredients are many +which are taken up by the plant simply because they are present in +the soil; others, on the other hand, as has been shown by numerous +classical investigations, are indispensable to plant growth. If any +one of these indispensable ash ingredients be absent, it is +impossible for a plant to mature on such a soil. In fact, it is +pretty well established that, providing the physical conditions and +the water supply are satisfactory, the fertility of a soil depends +largely upon the amount of available ash ingredients, or plant-food. + +A clear distinction must be made between the_ total _and _available +_plant-food. The essential plant-foods often occur in insoluble +combinations, valueless to plants; only the plant-foods that are +soluble in the soil-water or in the juices of plant roots are of +value to plants. It is true that practically all soils contain all +the indispensable plant-foods; it is also true, however, that in +most soils they are present, as available plant-foods, in +comparatively small quantities. When crops are removed from the land +year after year, without any return being made, it naturally follows +that under ordinary conditions the amount of available plant-food is +diminished, with a strong probability of a corresponding diminution +in crop-producing power. In fact, the soils of many of the older +countries have been permanently injured by continuous cropping, with +nothing returned, practiced through centuries. Even in many of the +younger states, continuous cropping to wheat or other crops for a +generation or less has resulted in a large decrease in the crop +yield. + +Practice and experiment have shown that such diminishing fertility +may be retarded or wholly avoided, first, by so working or +cultivating the soil as to set free much of the insoluble plant-food +and, secondly, by returning to the soil all or part of the +plant-food taken away. The recent development of the commercial +fertilizer industry is a response to this truth. It may be said +that, so far as the agricultural soils of the world are now known, +only three of the essential plant-foods are likely to be absent, +namely, potash, phosphoric acid, and nitrogen; of these, by far the +most important is nitrogen. The whole question of maintaining the +supply of plant-foods in the soil concerns itself in the main with +the supply of these three substances. + +The persistent fertility of dry-farms + +In recent years, numerous farmers and some investigators have stated +that under dry-farm conditions the fertility of soils is not +impaired by cropping without manuring. This view has been taken +because of the well-known fact that in localities where dry-farming +has been practiced on the same soils from twenty-five to forty-five +years, without the addition of manures, the average crop yield has +not only failed to diminish, but in most cases has increased. In +fact, it is the almost unanimous testimony of the oldest dry-farmers +of the United States, operating under a rainfall from twelve to +twenty inches, that the crop yields have increased as the cultural +methods have been perfected. If any adverse effect of the steady +removal of plant-foods has occurred, it has been wholly overshadowed +by other factors. The older dry-farms in Utah, for instance, which +are among the oldest of the country, have never been manured, yet +are yielding better to-day than they did a generation ago. Strangely +enough, this is not true of the irrigated farms, operating under +like soil and climatic conditions. This behavior of crop production +under dry-farm conditions has led to the belief that the question of +soil fertility is not an important one to dry-farmers. Nevertheless, +if our present theories of plant nutrition are correct, it is also +true that, if continuous cropping is practiced on our dry-farm soils +without some form of manuring, the time must come when the +productive power of the soils will be injured and the only recourse +of the farmer will be to return to the soils some of the plant-food +taken from it. + +The view that soil fertility is not diminished by dry-farming +appears at first sight to be strengthened by the results obtained by +investigators who have made determinations of the actual plant-food +in soils that have long been dry-farmed. The sparsely settled +condition of the dry-farm territory furnishes as yet an excellent +opportunity to compare virgin and dry-farmed lands and which +frequently may be found side by side in even the older dry-farm +sections. Stewart found that Utah dry-farm soils, cultivated for +fifteen to forty years and never manured, were in many cases richer +in nitrogen than neighboring virgin lands. Bradley found that the +soils of the great dry-farm wheat belt of Eastern Oregon contained, +after having been farmed for a quarter of a century, practically as +much nitrogen as the adjoining virgin lands. These determinations +were made to a depth of eighteen inches. Alway and Trumbull, on the +other hand, found in a soil from Indian Head, Saskatchewan, that in +twenty-five years of cultivation the total amount of nitrogen had +been reduced about one third, though the alternation of fallow and +crop, commonly practiced in dry-farming, did not show a greater loss +of soil nitrogen than other methods of cultivation. It must be kept +in mind that the soil of Indian Head contains from two to three +times as much nitrogen as is ordinarily found in the soils of the +Great Plains and from three to four times as much as is found in the +soils of the Great Basin and the High Plateaus. It may be assumed, +therefore, that the Indian Head soil was peculiarly liable to +nitrogen losses. Headden, in an investigation of the nitrogen +content of Colorado soils, has come to the conclusion that arid +conditions, like those of Colorado, favor the direct accumulation of +nitrogen in soils. All in all, the undiminished crop yield and the +composition of the cultivated fields lead to the belief that +soil-fertility problems under dry-farm conditions are widely +different from the old well-known problems under humid conditions. + +Reasons for dry-farming fertility + +It is not really difficult to understand why the yields and, +apparently, the fertility of dry-farms have continued to increase +during the period of recorded dry-farm history--nearly half a +century. + +First, the intrinsic fertility of arid as compared with humid soils +is very high. (See Chapter V.) The production and removal of many +successive bountiful crops would not have as marked an effect on +arid as on humid soils, for both yield and composition change more +slowly on fertile soils. The natural extraordinarily high fertility +of dry-farm soils explains, therefore, primarily and chiefly, the +increasing yields on dry-farm soils that receive proper cultivation. + +The intrinsic fertility of arid soils is not alone sufficient to +explain the increase in plant-food which undoubtedly occurs in the +upper foot or two of cultivated dry-farm lands. In seeking a +suitable explanation of this phenomenon it must be recalled that the +proportion of available plant-food in arid soils is very uniform to +great depths, and that plants grown under proper dry-farm conditions +are deep rooted and gather much nourishment from the lower soil +layers. As a consequence, the drain of a heavy crop does not fall +upon the upper few feet as is usually the case in humid soils. The +dry-farmer has several farms, one upon the other, which permit even +improper methods of farming to go on longer than would be the case +on shallower soils. + +The great depth of arid soils further permits the storage of rain +and snow water, as has been explained in previous chapters, to +depths of from ten to fifteen feet. As the growing season proceeds, +this water is gradually drawn towards the surface, and with it much +of the plant-food dissolved by the water in the lower soil layers. +This process repeated year after year results in a concentration in +the upper soil layers of fertility normally distributed in the soil +to the full depth reach by the soil-moisture. At certain seasons, +especially in the fall, this concentration may be detected with +greatest certainty. In general, the same action occurs in virgin +lands, but the methods of dry-farm cultivation and cropping which +permit a deeper penetration of the natural precipitation and a freer +movement of the soil-water result in a larger quantity of plant-food +reaching the upper two or three feet from the lower soil depths. +Such concentration near the surface, when it is not excessive, +favors the production of increased yields of crops. + +The characteristic high fertility and great depth of arid soils are +probably the two main factors explaining the apparent increase of +the fertility of dry-farms under a system of agriculture which does +not include the practice of manuring. Yet, there are other +conditions that contribute largely to the result. For instance, +every cultural method accepted in dry-farming, such as deep plowing, +fallowing, and frequent cultivation, enables the weathering forces +to act upon the soil particles. Especially is it made easy for the +air to enter the soil. Under such conditions, the plant-food +unavailable to plants because of its insoluble condition is +liberated and made available. The practice of dry-farming is of +itself more conducive to such accumulation of available plant food +than are the methods of humid agriculture. + +Further, the annual yield of any crop under conditions of +dry-farming is smaller than under conditions of high rainfall. Less +fertility is, therefore, removed by each crop and a given amount of +available fertility is sufficient to produce a large number of crops +without showing signs of deficiency. The comparatively small annual +yield of dry-farm crops is emphasized in view of the common practice +of summer fallowing, which means that the land is cropped only every +other year or possibly two years out of three. Under such conditions +the yield in any one year is cut in two to give an annual yield. + +The use of the header wherever possible in harvesting dry-farm grain +also aids materially in maintaining soil fertility. By means of the +header only the heads of the grain are clipped off: the stalks are +left standing. In the fall, usually, this stubble is plowed under +and gradually decays. In the earlier dry-farm days farmers feared +that under conditions of low rainfall, the stubble or straw plowed +under would not decay, but would leave the soil in a loose dry +condition unfavorable for the growth of plants. During the last +fifteen years it has been abundantly demonstrated that if the +correct methods of dry farming are followed, so that a fair balance +of water is always found in the soil, even in the fall, the heavy, +thick header stubble may be plowed into the soil with the certainty +that it will decay and thus enrich the soil. The header stubble +contains a very large proportion of the nitrogen that the crop has +taken from the soil and more than half of the potash and phosphoric +acid. Plowing under the header stubble returns all this material to +the soil. Moreover, the bulk of the stubble is carbon taken from the +air. This decays, forming various acid substances which act on the +soil grains to set free the fertility which they contain. At the end +of the process of decay humus is formed, which is not only a +storehouse of plant-food, but effective in maintaining a good +physical condition of the soil. The introduction of the header in +dry-farming was one of the big steps in making the practice certain +and profitable. + +Finally, it must be admitted that there are a great many more or +less poorly understood or unknown forces at work in all soils which +aid in the maintenance of soil-fertility. Chief among these are the +low forms of life known as bacteria. Many of these, under favorable +conditions, appear to have the power of liberating food from the +insoluble soil grains. Others have the power when settled on the +roots of leguminous or pod-bearing plants to fix nitrogen from the +air and convert it into a form suitable for the need of plants. In +recent years it has been found that other forms of bacteria, the +best known of which is azotobacter, have the power of gathering +nitrogen from the air and combining it for the plant needs without +the presence of leguminous plants. These nitrogen-gathering bacteria +utilize for their life processes the organic matter in the soil, +such as the decaying header stubble, and at the same time enrich the +soil by the addition of combined nitrogen. Now, it so happens that +these important bacteria require a soil somewhat rich in lime, well +aerated and fairly dry and warm. These conditions are all met on the +vast majority of our dry-farm soils, under the system of culture +outlined in this volume. Hall maintains that to the activity of +these bacteria must be ascribed the large quantities of nitrogen +found in many virgin soils and probably the final explanation of the +steady nitrogen supply for dry farms is to be found in the work of +the azatobacter and related forms of low life. The potash and +phosphoric acid supply can probably be maintained for ages by proper +methods of cultivation, though the phosphoric acid will become +exhausted long before the potash. The nitrogen supply, however, must +come from without. The nitrogen question will undoubtedly soon be +the one before the students of dry-farm fertility. A liberal supply +of organic matter In the soil with cultural methods favoring the +growth of the nitrogen-gathering bacteria appears at present to be +the first solution of the nitrogen question. Meanwhile, the activity +of the nitrogen-gathering bacteria, like azotobacter, is one of our +best explanations of the large presence of nitrogen in cultivated +dry-farm soils. + +To summarize, the apparent increase in productivity and plant-food +content of dry-farm soils can best be explained by a consideration +of these factors: (1) the intrinsically high fertility of the arid +soils; (2) the deep feeding ground for the deep root systems of +dry-farm crops; (3) the concentration of the plant food distributed +throughout the soil by the upward movement of the natural +precipitation stored in the soil; (4) the cultural methods of +dry-farming which enable the weathering agencies to liberate freely +and vigorously the plant-food of the soil grains; (5) the small +annual crops; (6) the plowing under of the header straw, and (7) the +activity of bacteria that gather nitrogen directly from the air. + +Methods of conserving soil-fertility + +In view of the comparatively small annual crops that characterize +dry-farming it is not wholly impossible that the factors above +discussed, if properly applied, could liberate the latent plant-food +of the soil and gather all necessary nitrogen for the plants. Such +an equilibrium, could it once be established, would possibly +continue for long periods of time, but in the end would no doubt +lead to disaster; for, unless the very cornerstone of modern +agricultural science is unsound, there will be ultimately a +diminution of crop producing power if continuous cropping is +practiced without returning to the soil a goodly portion of the +elements of soil fertility taken from it. The real purpose of modern +agricultural researeh is to maintain or increase the productivity of +our lands; if this cannot be done, modern agriculture is essentially +a failure. Dry-farming, as the newest and probably in the future one +of the greatest divisions of modern agriculture, must from the +beginning seek and apply processes that will insure steadiness in +the productive power of its lands. Therefore, from the very +beginning dry-farmers must look towards the conservation of the +fertility of their soils. + +The first and most rational method of maintaining the fertility of +the soil indefinitely is to return to the soil everything that is +taken from it. In practice this can be done only by feeding the +products of the farm to live stock and returning to the soil the +manure, both solid and liquid, produced by the animals. This brings +up at once the much discussed question of the relation between the +live stock industry and dry-farming. While it is undoubtedly true +that no system of agriculture will be wholly satisfactory to the +farmer and truly beneficial to the state, unless it is connected +definitely with the production of live stock, yet it must be +admitted that the present prevailing dry-farm conditions do not +always favor comfortable animal life. For instance, over a large +portion of the central area of the dry-farm territory the dry-farms +are at considerable distances from running or well water. In many +cases, water is hauled eight or ten miles for the supply of the men +and horses engaged in farming. Moreover, in these drier districts, +only certain crops, carefully cultivated, will yield profitably, and +the pasture and the kitchen garden are practical impossibilities +from an economic point of view. Such conditions, though profitable +dry-farming is feasible, preclude the existence of the home and the +barn on or even near the farm. When feed must be hauled many miles, +the profits of the live stock industry are materially reduced and +the dry-farmer usually prefers to grow a crop of wheat, the straw of +which may be plowed under the soil to the great advantage of the +following crop. In dry-farm districts where the rainfall is higher +or better distributed, or where the ground water is near the +surface, there should be no reason why dry-farming and live stock +should not go hand in hand. Wherever water is within reach, the +homestead is also possible. The recent development of the gasoline +motor for pumping purposes makes possible a small home garden +wherever a little water is available. The lack of water for culinary +purposes is really the problem that has stood between the joint +development of dry-farming and the live stock industry. The whole +matter, however, looks much more favorable to-day, for the efforts +of the Federal and state governments have succeeded in discovering +numerous subterranean sources of water in dry-farm districts. In +addition, the development of small irrigation systems in the +neighborhood of dry-farm districts is helping the cause of the live +stock industry. At the present time, dry-farming and the live stock +industry are rather far apart, though undoubtedly as the desert is +conquered they will become more closely associated. The question +concerning the best maintenance of soil-fertility remains the same; +and the ideal way of maintaining fertility is to return to the soil +as much as is possible of the plant-food taken from it by the crops, +which can best be accomplished by the development of the business of +keeping live stock in connection with dry-farming. + +If live stock cannot be kept on a dry-farm, the most direct method +of maintaining soil-fertility is by the application of commercial +fertilizers. This practice is followed extensively in the Eastern +states and in Europe. The large areas of dry-farms and the high +prices of commercial fertilizers will make this method of manuring +impracticable on dry-farms, and it may be dismissed from thought +until such a day as conditions, especially with respect to price of +nitrates and potash, are materially changed. + +Nitrogen, which is the most important plant-food that may be absent +from dry-farm soils, may be secured by the proper use of leguminous +crops. All the pod-bearing plants commonly cultivated, such as peas, +beans, vetch, clover, and lucern, are able to secure large +quantities of nitrogen from the air through the activity of bacteria +that live and grow on the roots of such plants. The leguminous crop +should be sown in the usual way, and when it is well past the +flowering stage should be plowed into the ground. Naturally, annual +legumes, such as peas and beans, should be used for this purpose. +The crop thus plowed under contains much nitrogen, which is +gradually changed into a form suitable for plant assimilation. In +addition, the acid substances produced in the decay of the plants +tend to liberate the insoluble plant-foods and the organic matter is +finally changed into humus. In order to maintain a proper supply of +nitrogen in the soil the dry-farmer will probably soon find himself +obliged to grow, every five years or oftener, a crop of legumes to +be plowed under. + +Non-leguminous crops may also be plowed under for the purpose of +adding organic matter and humus to the soil, though this has little +advantage over the present method of heading the grain and plowing +under the high stubble. The header system should be generally +adopted on wheat dry-farms. On farms where corn is the chief crop, +perhaps more importance needs to be given to the supply of organic +matter and humus than on wheat farms. The occasional plowing under +of leguminous crops would he the most satisfactory method. The +persistent application of the proper cultural methods of dry-farming +will set free the most important plant-foods, and on well-cultivated +farms nitrogen is the only element likely to be absent in serious +amounts. + +The rotation of crops on dry-farms is usually advocated in districts +like the Great Plains area, where the annual rainfall is over +fifteen inches and the major part of the precipitation comes in +spring and summer. The various rotations ordinarily include one or +more crops of small grains, a hoed crop like corn or potatoes, a +leguminous crop, and sometimes a fallow year. The leguminous crop is +grown to secure a fresh supply of nitrogen; the hoed crop, to enable +the air and sunshine to act thoroughly on the soil grains and to +liberate plant-food, such as potash and phosphoric acid; and the +grain crops to take up plant-food not reached by the root systems of +the other plants. The subject of proper rotation of crops has always +been a difficult one, and very little information exists on it as +practiced on dry-farms. Chilcott has done considerable work on +rotations in the Great Plains district, hut he frankly admits that +many years of trial will he necessary for the elucidation of +trustworthy principles. Some of the best rotations found by Chilcott +up to the present are:-- + + +Corn--Wheat--Oats +Barley--Oats--Corn +Fallow--Wheat--Oats + + +Rosen states that rotation is very commonly practiced in the dry +sections of southern Russia, usually including an occasional Summer +fallow. As a type of an eight-year rotation practiced at the Poltava +Station, the following is given: (1) Summer tilled and manured; (2) +winter wheat; (3) hoed crop; (4) spring wheat; (5) summer fallow; +(6) winter rye; (7) buckwheat or an annual legume; (8) oats. This +rotation, it may be observed, includes the grain crop, hoed crop, +legume, and fallow every four years. + +As has been stated elsewhere, any rotation in dry-farming which does +not include the summer fallow at least every third or fourth year is +likely to be dangerous In years of deficient rainfall. + +This review of the question of dry-farm fertility is intended merely +as a forecast of coming developments. At the present time +soil-fertility is not giving the dry-farmers great concern, but as +in the countries of abundant rainfall the time will come when it +will be equal to that of water conservation, unless indeed the +dry-farmers heed the lessons of the past and adopt from the start +proper practices for the maintenance of the plant-food stored in the +soil. The principle explained in Chapter IX, that the amount of +water required for the production of one pound of water diminishes +as the fertility increases, shows the intimate relationship that +exists between the soil-fertility and the soil-water and the +importance of maintaining dry-farm soils at a high state of +fertility. + + + + + + +CHAPTER XV + +IMPLEMENTS FOR DRY-FARMING + + + + + +Cheap land and relatively small acre yields characterize +dry-farming. Consequently Iarger areas must be farmed for a given +return than in humid farming, and the successful pursuit of +dry-farming compels the adoption of methods that enable a man to do +the largest amount of effective work with the smallest expenditure +of energy. The careful observations made by Grace, in Utah, lead to +the belief that, under the conditions prevailing in the +intermountain country, one man with four horses and a sufficient +supply of machinery can farm 160 acres, half of which is +summer-fallowed every year; and one man may, in favorable seasons +under a carefully planned system, farm as much as 200 acres. If one +man attempts to handle a larger farm, the work is likely to be done +in so slipshod a manner that the crop yield decreases and the total +returns are no larger than if 200 acres had been well tilled. + +One man with four horses would be unable to handle even 160 acres +were it not for the possession of modern machinery; and dry-farming, +more than any other system of agriculture, is dependent for its +success upon the use of proper implements of tillage. In fact, it is +very doubtful if the reclamation of the great arid and semiarid +regions of the world would have been possible a few decades ago, +before the invention and introduction of labor-saving farm +machinery. It is undoubtedly further a fact that the future of +dry-farming is closely bound up with the improvements that may be +made in farm machinery. Few of the agricultural implements on the +market to-day have been made primarily for dry-farm conditions. The +best that the dry-farmer can do is to adapt the implements on the +market to his special needs. Possibly the best field of +investigation for the experiment stations and inventive minds in the +arid region is farm mechanics as applied to the special needs of +dry-farming. + +Clearing and breaking + +A large portion of the dry-farm territory of the United States is +covered with sagebrush and related plants. It is always a difficult +and usually an expensive problem to clear sagebrush land, for the +shrubs are frequently from two to six feet high, correspondingly +deep-rooted, with very tough wood. When the soil is dry, it is +extremely difficult to pull out sagebrush, and of necessity much of +the clearing must be done during the dry season. Numerous devices +have been suggested and tried for the purpose of clearing sagebrush +land. One of the oldest and also one of the most effective devices +is two parallel railroad rails connected with heavy iron chains and +used as a drag over the sagebrush land. The sage is caught by the +two rails and torn out of the ground. The clearing is fairly +complete, though it is generally necessary to go over the ground two +or three times before the work is completed. Even after such +treatment a large number of sagebrush clumps, found standing over +the field, must be grubbed up with the hoe. Another and effective +device is the so-called "mankiller." This implement pulls up the +sage very successfully and drops it at certain definite intervals. +It is, however, a very dangerous implement and frequently results in +injury to the men who work it. Of recent years another device has +been tried with a great deal of success. It is made like a snow plow +of heavy railroad irons to which a number of large steel knives have +been bolted. Neither of these implements is wholly satisfactory, and +an acceptable machine for grubbing sagebrush is yet to be devised. +In view of the large expense attached to the clearing of sagebrush +land such a machine would be of great help in the advancement of +dry-farming. + +Away from the sagebrush country the virgin dry-farm land is usually +covered with a more or less dense growth of grass, though true sod +is seldom found under dry-farm conditions. The ordinary breaking +plow, characterized by a long sloping moldboard, is the best known +implement for breaking all kinds of sod. (See Fig. 7a a.) Where the +sod is very light, as on the far western prairies, the more ordinary +forms of plows may be used. In still other sections, the dry-farm +land is covered with a scattered growth of trees, frequently pinion +pine and cedars, and in Arizona and New Mexico the mesquite tree and +cacti are to be removed. Such clearing has to be done in accordance +with the special needs of the locality. + +Plowing + +Plowing, or the turning over of the soil to a depth of from seven to +ten inches for every crop, is a fundamental operation of +dry-farming. The plow, therefore, becomes one of the most important +implements on the dry-farm. Though the plow as an agricultural +implement is of great antiquity, it is only within the last one +hundred years that it has attained its present perfection. It is a +question even to-day, in the minds of a great many students, whether +the modern plow should not be replaced by some machine even more +suitable for the proper turning and stirring of the soil. The +moldboard plow is, everything considered, the most satisfactory plow +for dry-farm purposes. A plow with a moldboard possessing a short +abrupt curvature is generally held to be the most valuable for +dry-farm purposes, since it pulverizes the soil most thoroughly, and +in dry-farming it is not so important to turn the soil over as to +crumble and loosen it thoroughly. Naturally, since the areas of +dry-farms are very large, the sulky or riding plow is the only kind +to be used. The same may be said of all other dry-farm implements. +As far as possible, they should be of the riding kind since in the +end it means economy from the resulting saving of energy. + +The disk plow has recently come into prominent use throughout the +land. It consists, as is well known, of one or more large disks +which are believed to cause a smaller draft, as they cut into the +ground, than the draft due to the sliding friction upon the +moldboard. Davidson and Chase say, however, that the draft of a disk +plow is often heavier in proportion to the work done and the plow +itself is more clumsy than the moldboard plow. For ordinary dry-farm +purposes the disk plow has no advantage over the modern moldboard +plow. Many of the dry-farm soils are of a heavy clay and become very +sticky during certain seasons of the year. In such soils the disk +plow is very useful. It is also true that dry-farm soils, subjected +to the intense heat of the western sun become very hard. In the +handling of such soils the disk plow has been found to be most +useful. The common experience of dry-farmers is that when sagebrush +lands have been the first plowing can be most successfully done with +the disk plow, but that after. the first crop has been harvested, +the stubble land can be best handled with the moldboard plow. All +this, however, is yet to be subjected to further tests. + +While subsoiling results in a better storage reservoir for water and +consequently makes dry-farming more secure, yet the high cost of the +practice will probably never make it popular. Subsoiling is +accomplished in two ways: either by an ordinary moldboard plow which +follows the plow in the plow furrow and thus turns the soil to a +greater depth, or by some form of the ordinary subsoil plow. In +general, the subsoil plow is simply a vertical piece of cutting +iron, down to a depth of ten to eighteen inches, at the bottom of +which is fastened a triangular piece of iron like a shovel, which, +when pulled through the ground, tends to loosen the soil to the full +depth of the plow. + +The subsoil plow does not turn the soil; it simply loosens the soil +so that the air and plant roots can penetrate to greater depths. + +In the choice of plows and their proper use the dryfarmer must be +guided wholly by the conditions under which he is working. It is +impossible at the present time to lay down definite laws stating +what plows are best for certain soils. The soils of the arid region +are not well enough known, nor has the relationship between the plow +and the soil been sufficiently well established. As above remarked, +here is one of the great fields for investigation for both +scientific and practical men for years to come. + +Making and maintaining a soil-mulch + +After the land has been so well plowed that the rains can enter +easily, the next operation of importance in dry-farming is the +making and maintaining of a soil-mulch over the ground to prevent +the evaporation of water from the soil. For this purpose some form +of harrow is most commonly used. The oldest and best-known harrow is +the ordinary smoothing harrow, which is composed of iron or steel +teeth of various shapes set in a suitable frame. (See Fig. 79.) For +dry-farm purposes the implement must be so made as to enable the +farmer to set the harrow teeth to slant backward or forward. It +frequently happens that in the spring the grain is too thick for the +moisture in the soil, and it then becomes necessary to tear out some +of the young plants. For this purpose the harrow teeth are set +straight or forward and the crop can then be thinned effectively. At +other times it may be observed in the spring that the rains and +winds have led to the formation of a crust over the soil, which must +be broken to let the plants have full freedom of growth and +development. This is accomplished by slanting the harrow teeth +backward, and the crust may then be broken without serious injury to +the plants. The smoothing harrow is a very useful implement on the +dry-farm. For following the plow, however, a more useful implement +is the disk harrow, which is a comparatively recent invention. It +consists of a series of disks which may be set at various angles +with the line of traction and thus be made to turn over the soil +while at the same time pulverizing it. The best dry-farm practice is +to plow in the fall and let the soil lie in the rough during the +winter months. In the spring the land is thoroughly disked and +reduced to a fine condition. Following this the smoothing harrow is +occasionally used to form a more perfect mulch. When seeding is to +be done immediately after plowing, the plow is followed by the disk +harrow, and that in turn is followed by the smoothing harrow. The +ground is then ready for seeding. The disk harrow is also used +extensively throughout the summer in maintaining a proper mulch. It +does its work more effectively than the ordinary smoothing harrow +and is, therefore, rapidly displacing all other forms of harrows for +the purpose of maintaining a layer of loose soil over the dry-farm. +There are several kinds of disk harrows used by dry-farmers. The +full disk is, everything considered, the most useful. The cutaway +harrow is often used in cultivating old alfalfa land; the spade disk +harrow has a very limited application in dry-farming; and the +orchard disk harrow is simply a modlfication of the full disk harrow +whereby the farmer is able to travel between the rows of trees and +so to cultivate the soil under the branches of the trees without +injuring the leaves or fruit. + +One of the great difficulties in dry-farming concerns itself with +the prevention of the growth of weeds or volunteer crops. As has +been explained in previous chapters, weeds require as much water for +their growth as wheat or other useful crops. During the fallow +season, the farmer is likely to be overtaken by the weeds and lose +much of the value of the fallow by losing soil-moisture through the +growth of weeds. Under the most favorable conditions weeds are +difficult to handle. The disk harrow itself is not effective. The +smoothing harrow is of less value. There is at the present time +great need for some implement that will effectively destroy young +weeds and prevent their further growth. Attempts are being made to +invent such implements, but up to the present without great success. +Hogenson reports the finding of an implement on a western dry-farm +constructed by the farmer himself which for a number of years has +shown itself of high efficiency in keeping the dry-farm free from +weeds. Several improved modifications of this implement have been +made and tried out on the famous dry-farm district at Nephi, Utah, +and with the greatest success. Hunter reports a similar implement in +common use on the dry-farms of the Columbia Basin. Spring tooth +harrows are also used in a small way on the dry-farms. + +They have no special advantage over the smoothing harrow or the disk +harrow, except in places where the attempt is made to cultivate the +soil between the rows of wheat. The curved knife tooth harrow is +scareely ever used on dry-farms. It has some value as a pulverizer, +but does not seem to have any real advantage over the ordinary disk +harrow. + +Cultivators for stirring the land on which crops are growing are not +used extensively on dry-farms. Usually the spring tooth harrow is +employed for this work. In dry-farm sections, where corn is grown, +the cultivator is frequently used throughout the season. Potatoes +grown on dry-farms should be cultivated throughout the season, and +as the potato industry grows in the dry-farm territory there will be +a greater demand for suitable cultivators. The cultivators to be +used on dry-farms are all of the riding kind. They should be so +arranged that the horse walking between two rows carries a +cultivator that straddles several rows of plants and cultivates the +soil between. Disks, shovels, or spring teeth may be used on +cultivators. There is a great variety on the market, and each farmer +will have to choose such as meet most definitely his needs. + +The various forms of harrows and cultivators are of the greatest +importance in the development of dry-farming. Unless a proper mulch +can be kept over the soil during the fallow season, and as far as +possible during the growing season, first-class crops cannot be +fully respected. + +The roller is occasionally used in dry-farming, especially in the +uplands of the Columbia Basin. It is a somewhat dangerous implement +to use where water conservation is important, since the packing +resulting from the roller tends to draw water upward from the lower +soil layers to be evaporated into the air. Wherever the roller is +used, therefore, it should be followed immediately by a harrow. It +is valuable chiefly in the localities where the soil is very loose +and light and needs packing around the seeds to permit perfect +germination. + +Subsurface packing + +The subsurface packer invented by Campbell is [shown in Figure +83--not shown--ed.]. The wheels of this machine eighteen inches in +diameter, with rims one inch thick at the inner part, beveled two +and a half inches to a sharp outer edge, are placed on a shaft, five +inches apart. In practice about five hundred pounds of weight are +added. + +This machine, according to Campbell, crowds a one-inch wedge into +every five inches of soil with a lateral and a downward pressure and +thus packs firmly the soil near the bottom of the plow-furrow. +Subsurface packing aims to establish full capillary connection +between the plowed upper soil and the undisturbed lower soil-layer; +to bring the moist soil in close contact with the straw or organic +litter plowed under and thus to hasten decomposition, and to provide +a firm seed bed. + +The subsurface packer probably has some value where the plowed soil +containing the stubble is somewhat loose; or on soils which do not +permit of a rapid decay of stubble and other organic matter that may +be plowed under from season to season. On such soils the packing +tendency of the subsurface packer may help prevent loss of soil +water, and may also assist in furnishing a more uniform medium +through which plant roots may force their way. For all these +purposes, the disk is usually equally efficient. + +Sowing + +It has already been indicated in previous chapters that proper +sowing is one of the most important operations of the dry-farm, +quite comparable in importance with plowing or the maintaining of a +mulch for retaining soil-moisture. The old-fashioned method of +broadcasting has absolutely no place on a dry-farm. The success of +dry-farming depends entirely upon the control that the farmer has of +all the operations of the farm. By broadcasting, neither the +quantity of seed used nor the manner of placing the seed in the +ground can be regulated. Drill culture, therefore, introduced by +Jethro Tull two hundred years ago, which gives the farmer full +control over the process of seeding, is the only system to be used. +The numerous seed drills on the market all employ the same +principles. Their variations are few and simple. In all seed drills +the seed is forced into tubes so placed as to enable the seed to +fall into the furrows in the ground. The drills themselves are +distinguished almost wholly by the type of the furrow opener and the +covering devices which are used. The seed furrow is opened either by +a small hoe or a so-called shoe or disk. At the present time it +appears that the single disk is the coming method of opening the +seed furrow and that the other methods will gradually disappear. As +the seed is dropped into the furrow thus made it is covered by some +device at the rear of the machine. One of the oldest methods as well +as one of the most satisfactory is a series of chains dragging +behind the drill and covering the furrow quite completely. It is, +however, very desirable that the soil should be pressed carefully +around the seed so that germination may begin with the least +difficulty whenever the temperature conditions are right. Most of +the drills of the day are, therefore, provided with large light +wheels, one for each furrow, which press lightly upon the soil and +force the soil into intimate contact with the seed The weakness of +such an arrangement is that the soil along the drill furrows is left +somewhat packed, which leads to a ready escape of the soil-moisture. +Many of the drills are so arranged that press wheels may be used at +the pleasure of the farmer. The seed drill is already a very useful +implement and is rapidly being made to meet the special requirements +of the dry-farmer. Corn planters are used almost exclusively on +dry-farms where corn is the leading crop. In principle they are very +much the same as the press drills. Potatoes are also generally +planted by machinery. Wherever seeding machinery has been +constructed based upon the principles of dry-farming, it is a very +advantageous adjunct to the dry-farm. + +Harvesting + +The immense areas of dry-farms are harvested almost wholly by the +most modern machinery. For grain, the harvester is used almost +exclusively in the districts where the header cannot be used, but +wherever conditions permit, the header is and should be used. It has +been explained in previous chapters how valuable the tall header +stubble is when plowed under as a means of maintaining the fertility +of the soil. Besides, there is an ease in handling the header which +is not known with the harvester. There are times when the header +leads to some waste as, for instance, when the wheat is very low and +heads are missed as the machine passes over the ground. In many +sections of the dry-farm territory the climatic conditions are such +that the wheat cures perfectly while still standing. In such places +the combined harvester and thresher is used. The header cuts off the +heads of the grain, which are passed up into the thresher, and bags +filled with threshed grain are dropped along the path of the +machine, while the straw is scattered over the ground. Wherever such +a machine can be used, it has been found to be economical and +satisfactory. Of recent years corn stalks have been used to better +advantage than in the past, for not far from one half of the feeding +value of the corn crop is in the stalks, which up to a few years ago +were very largely wasted. Corn harvesters are likewise on the market +and are quite generally used. It was manifestly impossible on large +places to harvest corn by hand and large corn harvesters have, +therefore, been made for this purpose. + +Steam and other motive power + +Recently numerous persons have suggested that the expense of running +a dry-farm could be materially reduced by using some motive power +other than horses. Steam, gasoline, and electricity have all been +suggested. The steam traction engine is already a fairly +well-developed machine and it has been used for plowing purposes on +many dry-farms in nearly all the sections of the dry-farm territory. +Unfortunately, up to the present it has not shown itself to be very +satisfactory. First of all it is to be remembered that the +principles of dry-farming require that the topsoil be kept very +loose and spongy. The great traction engines have very wide wheels +of such tremendous weight that they press down the soil very +compactly along their path and in that way defeat one of the +important purposes of tillage. Another objection to them is that at +present their construction is such as to result in continual +breakages. While these breakages in themselves are small and +inexpensive, they mean the cessation of all farming operations +during the hour or day required for repairs. A large crew of men is +thus left more or less idle, to the serious injury of the work and +to the great expense of the owner. Undoubtedly, the traction engine +has a place in dry-farming, but it has not yet been perfected to +such a degree as to make it satisfactory. On heavy soils it is much +more useful than on light soils. When the traction engine works +satisfactorily, plowing may be done at a cost considerably lower +than when horses are employed. + +In England, Germany, and other European countries some of the +difficulties connected with plowing have been overcome by using two +engines on the two opposite sides of a field. These engines move +synchronously together and, by means of large cables, plows, +harrows, or seeders, are pulled back and forth over the field. This +method seems to give good satisfaction on many large estates of the +old world. Macdonald reports that such a system is in successful +operation in the Transvaal in South Africa and is doing work there +at a very knew cost. The large initial cost of such a system will, +of course, prohibit its use except on the very large farms that are +being established in the dry-farm territory. + +Gasoline engines are also being tried out, but up to date they have +not shown themselves as possessing superior advantages over the +steam engines. The two objections to them are the same as to the +steam engine: first, their great weight, which compresses in a +dangerous degree the topsoil and, secondly, the frequent breakages, +which make the operation slow and expensive. + +Over a great part of the West, water power is very abundant and the +suggestion has been made that the electric energy which can be +developed by means of water power could be used in the cultural +operations of the dry-farm. With the development of the trolley car +which does not run on rails it would not seem impossible that in +favorable localities electricity could be made to serve the farmer +in the mechanical tillage of the dry-farm. + +The substitution of steam and other energy for horse power is yet in +the future. Undoubtedly, it will come, but only as improvements are +made in the machines. There is here also a great field for being of +high service to the farmers who are attempting to reclaim the great +deserts of the world. As stated at the beginning of this chapter, +dry-farming would probably have been an impossibilityfifty or a +hundred years ago because of the absence of suitable machinery. The +future of dry-farming rests almost wholly, so far as its profits are +concerned, upon the development of new and more suitable machinery +for the tillage of the soil in accordance with the established +principles of dry-farming. + +Finally, the recommendations made by Merrill may here be inserted. A +dry-farmer for best work should be supplied with the following +implements in addition to the necessary wagons and hand tools:-- + + +One Plow. +One Disk. +One Smoothing Harrow. +One Drill Seeder. +One Harvester or Header. +One Mowing Machine. + + + + + + + +CHAPTER XVI + +IRRIGATION AND DRY-FARMING + + + + + +Irrigation-farming and dry-farming are both systems of agriculture +devised for the reclamation of countries that ordinarily receive an +annual rainfall of twenty inches or less. Irrigation-farming cannot +of itself reclaim the arid regions of the world, for the available +water supply of arid countries when it shall have been conserved in +the best possible way cannot be made to irrigate more than one fifth +of the thirsty land. This means that under the highest possible +development of irrigation, at least in the United States, there will +be five or six acres of unirrigated or dry-farm land for every acre +of irrigated land. Irrigation development cannot possibly, +therefore, render the dry-farm movement valueless. On the other +hand, dry-farming is furthered by the development of irrigation +farming, for both these systems of agriculture are characterized by +advantages that make irrigation and dry-farming supplementary to +each other in the successful development of any arid region. + +Under irrigation, smaller areas need to be cultivated for the same +crop returns, for it has been amply demonstrated that the acre +yields under proper irrigation are very much larger than the best +yields under the most careful system of dry-farming. Secondly, a +greater variety of crops may be grown on the irrigated farm than on +the dry-farm. As has already been shown in this volume, only certain +drouth resistant crops can be grown profitably upon dry-farms, and +these must be grown under the methods of extensive farming. The +longer growing crops, including trees, succulent vegetables, and a +variety of small fruits, have not as yet been made to yield +profitably under arid conditions without the artificial application +of water. Further, the irrigation-farmer is not largely dependent +upon the weather and, therefore, carries on this work with a feeling +of greater security. Of course, it is true that the dry years affect +the flow of water in the canals and that the frequent breaking of +dams and canal walls leaves the farmer helpless in the face of the +blistering heat. Yet, all in all, a greater feeling of security is +possessed by the irrigation farmer than by the dry-farmer. + +Most important, however, are the temperamental differences in men +which make some desirous of giving themselves to the cultivation of +a small area of irrigated land under intensive conditions and others +to dry-farming under extensive conditions. In fact, it is being +observed in the arid region that men, because of their temperamental +differences, are gradually separating into the two classes of +irrigation-farmers and dry-farmers. The dry-farms of necessity cover +much larger areas than the irrigated farms. The land is cheaper and +the crops are smaller. The methods to be applied are those of +extensive farming. The profits on the investment also appear to be +somewhat larger. The very necessity of pitting intellect against the +fierceness of the drouth appears to have attracted many-men to the +dry-farms. Gradually the certainty of producing crops on dry-farms +from season to season is becoming established, and the essential +difference between the two kinds of farming in the arid districts +will then he the difference between intensive and extensive methods +of culture. Men will be attracted to one or other of these systems +of agriculture according to their personal inclinations. + +The scarcity of water + +For the development of a well-rounded commonwealth in an arid region +it is, of course, indispensable that irrigation be practiced, for +dry-farming of itself will find it difficult to build up populous +cities and to supply the great variety of crops demanded by the +modern family. In fact, one of the great problems before those +engaged in the development of dry-farming at present is the +development of homesteads in the dry-farms. A homestead is possible +only where there is a sufficient amount of free water available for +household and stock purposes. In the portion of the dry-farm +territory where the rainfall approximates twenty inches, this +problem is not so very difficult, since ground water may be reached +easily. In the drier portions, however, where the rainfall is +between ten and fifteen inches, the problem is much more important. +The conditions that bring the district under the dry-farm +designation imply a scarcity of water. On few dry-farms is water +available for the needs of the household and the barns. In the Rocky +Mountain states numerous dry-farms have been developed from seven to +fifteen miles from the nearest source of water, and the main expense +of developing these farms has been the hauling of water to the farms +to supply the needs of the men and beasts at work on them. +Naturally, it is impossible to establish homesteads on the dry-farms +unless at least a small supply of water is available; and +dry-farming will never he what it might be unless happy homes can be +established upon the farms in the arid regions that grow crops +without irrigation. To make a dry-farm homestead possible enough +water must be available, first of all, to supply the culinary needs +of the household. This of itself is not large and, as will be shown +hereafter, may in most cases be obtained. However, in order that the +family may possess proper comforts, there should be around the +homestead trees, and shrubs, and grasses, and the family garden. To +secure these things a certain amount of irrigation water is +required. It may be added that dry-farms on which such homesteads +are found as a result of the existence of a small supply of +irrigation water are much more valuable, in case of sale, than +equally good farms without the possibility of maintaining +homesteads. Moreover, the distinct value of irrigation in producing +a large acre yield makes it desirable for the farmer to use all the +water at his disposal for irrigation purposes. No available water +should be allowed to flow away unused. + +Available surface water + +The sources of water for dry-farms fall readily into classes: +surface waters and subterranean waters. The surface waters, wherever +they may be obtained, are generally the most profitable. The +simplest method of obtaining water in an irrigated region is from +some irrigation canal. In certain districts of the intermountain +region where the dry farms lie above the irrigation canals and the +irrigated lands below, it is comparatively easy for the farmers to +secure a small but sufficient amount of water from the canal by the +use of some pumping device that will force the water through the +pipes to the homestead. The dry-farm area that may be so supplied by +irrigation canals is, however, very limited and is not to be +considered seriously in connection with the problem. + +A much more important method, especially in the mountainous +districts, is the utilization of the springs that occur in great +numbers over the whole dry-farm territory. Sometimes these springs +are very small indeed, and often, after development by tunneling +into the side of the hill, yield only a trifling flow. Yet, when +this water is piped to the homestead and allowed to accumulate in +small reservoirs or cisterns, it may be amply sufficient for the +needs of the family and the live stock, besides having a surplus for +the maintenance of the lawn, the shade trees, and the family garden. +Many dry-farmers in the intermountain country have piped water seven +or eight miles from small springs that were considered practically +worthless and thereby have formed the foundations for small village +communities. + +Of perhaps equal importance with the utilization of the naturally +occurring springs is the proper conservation of the flood waters. As +has been stated before, arid conditions allow a very large loss of +the natural precipitation as run-off. The numerous gullies that +characterize so many parts of the dry-farm territory are evidences +of the number and vigor of the flood waters. The construction of +small reservoirs in proper places for the purpose of catching the +flood waters will usually enable the farmer to supply himself with +all the water needed for the homestead. Such reservoirs may already +be found in great numbers scattered over the whole western America. +As dry-farming increases their numbers will also increase. + +When neither canals, nor springs, nor flood waters are available for +the supply of water, it is yet possible to obtain a limited supply +by so arranging the roof gutters on the farm buildings that all the +water that falls on the roofs is conducted through the spouts into +carefully protected cisterns or reservoirs. A house thirty by thirty +feet, the roof of which is so constructed that all that water that +falls upon it is carried into a cistern will yield annually under a +a rainfall of fifteen inches a maximum amount of water equivalent to +about 8800 gallons. Allowing for the unavoidable waste due to +evaporation, this will yield enough to supply a household and some +live stock with the necessary water. In extreme cases this has been +found to be a very satisfactory practice, though it is the one to be +resorted to only in case no other method is available. + +It is indispensable that some reservoir be provided to hold the +surface water that may be obtained until the time it may be needed. +The water coming constantly from a spring in summer should be +applied to crops only at certain definite seasons of the year. The +flood waters usually come at a time when plant growth is not active +and irrigation is not needed. + +The rainfall also in many districts comes most largely at seasons of +no or little plant growth. Reservoirs must, therefore, be provided +for the storing of the water until the periods when it is demanded +by crops. Cement-lined cisterns are quite common, and in many places +cement reservoirs have been found profitable. In other places the +occurrence of impervious clay has made possible the establishment +and construction of cheap reservoirs. The skillful and permanent +construction of reservoirs is a very important subject. Reservoir +building should be undertaken only after a careful study of the +prevailing conditions and under the advice of the state or +government officials having such work in charge. In general, the +first cost of small reservoirs is usually somewhat high, but in view +of their permanent service and the value of the water to the +dry-farm they pay a very handsome interest on the investment. It is +always a mistake for the dry-farmer to postpone the construction of +a reservoir for the storing of the small quantities of water that he +may possess, in order to save a little money. Perhaps the greatest +objection to the use of the reservoirs is not their relatively high +cost, but the fact that since they are usually small and the water +shallow, too large a proportion of the water, even under favorable +conditions, is lost by evaporation. It is ordinarily assumed that +one half of the water stored in small reservoirs throughout the year +is lost by direct evaporation. + +Available subterranean water + +Where surface waters are not readily available, the subterranean +water is of first importance. It is generally known that, underlying +the earth's surface at various depths, there is a large quantity of +free water. Those living in humid climates often overestimate the +amount of water so held in the earth's crust, and it is probably +true that those living in arid regions underestimate the quantity of +water so found. The fact of the matter seems to be that free water +is found everywhere under the earth's surface. Those familiar with +the arid West have frequently been surprised by the frequency with +which water has been found at comparatively shallow depths in the +most desert locations. Various estimates have been made as to the +quantity of underlying water. The latest calculation and perhaps the +most reliable is that made by Fuller, who, after a careful analysis +of the factors involved, concludes that the total free water held in +the earth's crust is equivalent to a uniform sheet of water over the +entire surface of the earth ninety-six feet in depth. A quantity of +water thus held would be equivalent to about one hundredth part of +the whole volume of the ocean. Even though the thickness of the +water sheet under arid soils is only half this figure there is an +amount, if it could be reached, that would make possible the +establishment of homesteads over the whole dry-farm territory. One +of the main efforts of the day is the determination of the +occurrence of the subterranean waters in the dry-farm territory. + +Ordinary dug wells frequently reach water at comparatively shallow +depths. Over the cultivated Utah deserts water is often found at a +depth of twenty-five or thirty feet, though many wells dug to a +depth of one hundred and seventy-five and two hundred feet have +failed to reach water. It may be remarked in this connection that +even where the distance to the water is small, the piped well has +been found to be superior to the dug well. Usually, water is +obtained in the dry-farm territory by driving pipes to comparatively +great depths, ranging from one hundred feet to over one thousand +feet. At such depths water is nearly always found. Often the +geological conditions are such as to force the water up above the +surface as artesian wells, though more often the pressure is simply +sufficient to bring the water within easy pumping distance of the +surface. In connection with this subject it must be said that many +of the subterranean waters of the dry-farm territory are of a saline +character. The amount of substances held in solution varies largely, +but frequently is far above the limits of safety for the use of man +or beast or plants. The dry-farmer who secures a well of this type +should, therefore, be careful to have a proper examination made of +the constituents of the water before ordinary use is made of it. + +Now, as has been said, the utilization of the subterranean waters of +the land is one of the living problems of dry-farming. The tracing +out of this layer of water is very difficult to accomplish and +cannot be done by individuals. It is a work that properly belongs to +the state and national government. The state of Utah, which was the +pioneer in appropriating money for dry-farm experiments, also led +the way in appropriating money for the securing of water for the +dry-farms from subterranean sources. The world has been progressing +in Utah since 1905, and water has been secured in the most +unpromising localities. The most remarkable instance is perhaps the +finding of water at a depth of about five hundred and fifty feet in +the unusually dry Dog Valley located some fifteen miles west of +Nephi. + +Pumping water + +The use of small quantities of water on the dry-farms carries with +it, in most cases, the use of small pumping plants to store and to +distribute the water properly. Especially, whenever subterranean +sources of water are used and the water pressure is not sufficient +to throw the water above the ground, pumping must be resorted to. +The pumping of water for agricultural purposes is not at all new. +According to Fortier, two hundred thousand acres of land are +irrigated with water pumped from driven wells in the state of +California alone. Seven hundred and fifty thousand acres are +irrigated by pumping in the United States, and Mead states that +there are thirteen million acres of land in India which are +irrigated by water pumped from subterranean sources. The dry-farmer +has a choice among several sources of power for the operation of his +pumping plant. In localities where winds are frequent and of +sufficient strength windmills furnish cheap and effective power, +especially where the lift is not very great. The gasoline engine is +in a state of considerable perfection and may be used economically +where the price of gasoline is reasonable. Engines using crude oil +may be most desirable in the localities where oil wells have been +found. As the manufacture of alcohol from the waste products of the +farms becomes established, the alcohol-burning engine could become a +very important one. Over nearly the whole of the dry-farm territory +coal is found in large quantities, and the steam engine fed by coal +is an important factor in the pumping of water for irrigation +purposes. Further, in the mountainous part of the dry-farm territory +water Power is very abundant. Only the smallest fraction of it has +as yet been harnessed for the generation of the electric current. As +electric generation increases, it should be comparatively easy for +the farmer to secure sufficient electric power to run the pump. This +has already become an established practice in districts where +electric power is available. + +During the last few years considerable work has been done to +determine the feasibility of raising water for irrigation by +pumping. Fortier reports that successful results have been obtained +in Colorado, Wyoming, and Montana. He declares that a good type of +windmill located in a district where the average wind movement is +ten miles per hour can lift enough water twenty feet to irrigate +five acres of land. Wherever the water is near the surface this +should be easy of accomplishment. Vernon, Lovett, and Scott, who +worked under New Mexico conditions, have reported that crops can be +produced profitably by the use of water raised to the surface for +irrigation. Fleming and Stoneking, who conducted very careful +experiments on the subject in New Mexico, found that the cost of +raising through one foot a quantity of water corresponding to a +depth of one foot over one acre of land varied from a cent and an +eighth to nearly twenty-nine cents, with an average of a little more +than ten cents. This means that the cost of raising enough water to +cover one acre to a depth of one foot through a distance of forty +feet would average $4.36. This includes not only the cost of the +fuel and supervision of the pump but the actual deterioration of the +plant. Smith investigated the same problem under Arizona conditions +and found that it cost approximately seventeen cents to raise one +acre foot of water to a height of one foot. A very elaborate +investigation of this nature was conducted in California by Le Conte +and Tait. They studied a large number of pumping plants in actual +operation under California conditions, and determined that the total +cost of raising one acre foot of water one foot was, for gasoline +power, four cents and upward; for electric power, seven to sixteen +cents, and for steam, four cents and upward. Mead has reported +observations on seventy-two windmills near Garden City, Kansas, +which irrigated from one fourth to seven acres each at a cost of +seventy-five cents to $6 per acre. All in all, these results justify +the belief that water may be raised profitably by pumping for the +purpose of irrigating crops. When the very great value of a little +water on a dry-farm is considered, the figures here given do not +seem at all excessive. It must be remarked again that a reservoir of +some sort is practically indispensable in connection with a pumping +plant if the irrigation water is to be used in the best way. + +The use of small quantities of water in irrigation + +Now, it is undoubtedly true that the acre cost of water on +dry-farms, where pumping plants or similar devices must be used with +expensive reservoirs, is much higher than when water is obtained +from gravity canals. It is, therefore, important that the costly +water so obtained be used in the most economical manner. This is +doubly important in view of the fact that the water supply obtained +on dry-farms is always small and insufficient for all that the +farmer would like to do. Indeed, the profit in storing and pumping +water rests largely upon the economical application of water to +crops. This necessitates the statement of one of the first +principles of scientific irrigation practices, namely, that the +yield of a crop under irrigation is not proportional to the amount +of water applied in the form of irrigation water. In other words, +the water stored in the soil by the natural precipitation and the +water that falls during the spring and summer can either mature a +small crop or bring a crop near maturity. A small amount of water +added in the form of irrigation water at the right time will usually +complete the work and produce a well-matured crop of large yield. +Irrigation should only be supplemented to the natural precipitation. +As more irrigation water is added, the increase in yield becomes +smaller in proportion to the amount of water employed. This is +clearly shown by the following table, which is taken from some of +the irrigation experiments carried on at the Utah Station:-- + + +Effect of Varying Irrigations on Crop Yields Per Acre + +Depth of Water Wheat Corn Alfalfa Potatoes Sugar Beets +Applied (Inches) (Bushels) (Bushels) (Pounds) (Bushels) (Tons) +5.0 40 194 25 +7.5 41 65 +10.0 41 80 213 26 +15.0 46 78 253 27 +25.0 49 77 10,056 258 +35.0 55 9,142 291 26 +50 60 84 13,061 + + +The soil was a typical arid soil of great depth and had been so +cultivated as to contain a large quantity of the natural +precipitation. The first five inches of water added to the +precipitation already stored in the soil produced forty bushels of +wheat. Doubling this amount of irrigation water produced only +forty-one bushels of wheat. Even with an irrigation of fifty inches, +or ten times that which produced forty bushels, only sixty bushels +of wheat, or an increase of one half, were produced. A similar +variation may be observed in the case of the other crops. The first +lesson to be drawn from this important principle of irrigation is +that if the soil be so treated as to contain at planting time the +largest proportion of the natural precipitation,--that is, if the +ordinary methods of dry-farming be employed,--crops will be produced +with a very small amount of irrigation water. Secondly, it follows +that it would be a great deal better for the farmer who raises +wheat, for instance, to cover ten acres of land with water to a +depth of five inches than to cover one acre to a depth of fifty +inches, for in the former case four hundred bushels and in the +second sixty bushels of wheat would be produced. The farmer who +desires to utilize in the most economical manner the small amount of +water at his disposal must prepare the land according to dry-farm +methods and then must spread the water at his disposal over a larger +area of land. The land must be plowed in the fall if the conditions +permit, and fallowing should be practiced wherever possible. If the +farmer does not wish to fallow his family garden he can achieve +equally good results by planting the rows twice as far apart as is +ordinarily the case and by bringing the irrigation furrows near the +rows of plants. Then, to make the best use of the water, he must +carefully cover the irrigation furrow with dry dirt immediately +after the water has been applied and keep the whole surface well +stirred so that evaporation will be reduced to a minimum. The +beginning of irrigation wisdom is always the storage of the natural +precipitation. When that is done correctly, it is really remarkable +how far a small amount of irrigation water may be made to go. + +Under conditions of water scarcity it is often found profitable to +carry water to the garden in cement or iron pipes so that no water +may be lost by seepage or evaporation during the conveyance of the +water from the reservoir to the garden. It is also often desirable +to convey water to plants through pipes laid under the ground, +perforated at various intervals to allow the water to escape and +soak into the soil in the neighborhood of the plant roots. All such +refined methods of irrigation should be carefully investigated by +the who wants the largest results from his limited water supply. +Though such methods may seem cumbersome and expensive at first, yet +they will be found, if properly arranged, to be almost automatic in +their operation and also very profitable. + +Forbes has reported a most interesting experiment dealing with the +economical use of a small water supply under the long season and +intense water dissipating conditions of Arizona. The source of +supply was a well, 90 feet deep. A 3 by 14-inch pump cylinder +operated by a 12-foot geared windmill lifted the water into a +5000-gallon storage reservoir standing on a support 18 feet high. +The water was conveyed from this reservoir through black iron pipes +buried 1 or 2 feet from the trees to be watered. Small holes in the +pipe 332 inch in diameter allowed the water to escape at desirable +intervals. This irrigation plant was under expert observation for +considerable time, and it was found to furnish sufficient water for +domestic use for one household, and irrigated in addition 61 olive +trees, 2 cottonwoods, 8 pepper trees, 1 date palm, 19 pomegranates, +4 grapevines, 1 fig tree, 9 eucalyptus trees, 1 ash, and 13 +miscellancous, making a total of 87 useful trees, mainly +fruit-bearing, and 32 vines and bushes. (See Fig. 95.) If such a +result can be obtained with a windmill and with water ninety feet +below the surface under the arid conditions of Arizona, there should +be little difficulty in securing sufficient water over the larger +portions of the dry-farm territory to make possible beautiful +homesteads. + +The dry-farmer should carefully avoid the temptation to decry +irrigation practices. Irrigation and dry-farming of necessity must +go hand in hand in the development of the great arid regions of the +world. Neither can well stand alone in the building of great +commonwealths on the deserts of the earth. + + + + + + +CHAPTER XVII + +THE HISTORY OF DRY-FARMING + + + + + +The great nations of antiquity lived and prospered in arid and +semiarid countries. In the more or less rainless regions of China, +Mesopotamia, Palestine, Egypt, Mexico, and Peru, the greatest cities +and the mightiest peoples flourished in ancient days. Of the great +civilizations of history only that of Europe has rooted in a humid +climate. As Hilgard has suggested, history teaches that a high +civilization goes hand in hand with a soil that thirsts for water. +To-day, current events point to the arid and semiarid regions as the +chief dependence of our modern civilization. + +In view of these facts it may be inferred that dry-farming is an +ancient practice. It is improbable that intelligent men and women +could live in Mesopotamia, for example, for thousands of years +without discovering methods whereby the fertile soils could be made +to produce crops in a small degree at least without irrigation. +True, the low development of implements for soil culture makes it +fairly certain that dry-farming in those days was practiced only +with infinite labor and patience; and that the great ancient nations +found it much easier to construct great irrigation systems which +would make crops certain with a minimum of soil tillage, than so +thoroughly to till the soil with imperfect implements as to produce +certain yields without irrigation. Thus is explained the fact that +the historians of antiquity speak at length of the wonderful +irrigation systems, but refer to other forms of agriculture in a +most casual manner. While the absence of agricultural machinery +makes it very doubtful whether dry-farming was practiced extensively +in olden days, yet there can be little doubt of the high antiquity +of the practice. + +Kearney quotes Tunis as an example of the possible extent of +dry-farming in early historical days. Tunis is under an average +rainfall of about nine inches, and there are no evidences of +irrigation having been practiced there, yet at El Djem are the ruins +of an amphitheater large enough to accommodate sixty thousand +persons, and in an area of one hundred square miles there were +fifteen towns and forty-five villages. The country, therefore, must +have been densely populated. In the seventh century, according to +the Roman records, there were two million five hundred thousand +acres of olive trees growing in Tunis and cultivated without +irrigation. That these stupendous groves yielded well is indicated +by the statement that, under the Caesar's Tunis was taxed three +hundred thousand gallons of olive oil annually. The production of +oil was so great that from one town it was piped to the nearest +shipping port. This historical fact is borne out by the present +revival of olive culture in Tunis, mentioned in Chapter XII. + +Moreover, many of the primitive peoples of to-day, the Chinese, +Hindus, Mexicans, and the American Indians, are cultivating large +areas of land by dry-farm methods, often highly perfected, which +have been developed generations ago, and have been handed down to +the present day. Martin relates that the Tarahumari Indians of +northern Chihuahua, who are among the most thriving aboriginal +tribes of northern Mexico, till the soil by dry-farm methods and +succeed in raising annually large quantities of corn and other +crops. A crop failure among them is very uncommon. The early +American explorers, especially the Catholic fathers, found +occasional tribes in various parts of America cultivating the soil +successfully without irrigation. All this points to the high +antiquity of agriculture without irrigation in arid and semiarid +countries. + +Modern dry-farming in the United States + +The honor of having originated modern dry-farming belongs to the +people of Utah. On July 24th, 1847, Brigham Young with his band of +pioneers entered Great Salt Lake Valley, and on that day ground was +plowed, potatoes planted, and a tiny stream of water led from City +Creek to cover this first farm. The early endeavors of the Utah +pioneers were devoted almost wholly to the construction of +irrigation systems. The parched desert ground appeared so different +from the moist soils of Illinois and Iowa, which the pioneers had +cultivated, as to make it seem impossible to produce crops without +irrigation. Still, as time wore on, inquiring minds considered the +possibility of growing crops without irrigation; and occasionally +when a farmer was deprived of his supply of irrigation water through +the breaking of a canal or reservoir it was noticed by the community +that in spite of the intense heat the plants grew and produced small +yields. + +Gradually the conviction grew upon the Utah pioneers that farming +without irrigation was not an impossibility; but the small +population were kept so busy with their small irrigated farms that +no serious attempts at dry-farming were made during the first seven +or eight years. The publications of those days indicate that +dry-farming must have been practiced occasionally as early as 1854 +or 1855. + +About 1863 the first dry-farm experiment of any consequence occurred +in Utah. A number of emigrants of Scandinavian descent had settled +in what is now known as Bear River City, and had turned upon their +farms the alkali water of Malad Creek, and naturally the crops +failed. In desperation the starving settlers plowed up the sagebrush +land, planted grain, and awaited results. To their surprise, fair +yields of grain were obtained, and since that day dry-farming has +been an established practice in that portion of the Great Salt Lake +Valley. A year or two later, Christopher Layton, a pioneer who +helped to build both Utah and Arizona, plowed up land on the famous +Sand Ridge between Salt Lake City and Ogden and demonstrated that +dry-farm wheat could be grown successfully on the deep sandy soil +which the pioneers had held to be worthless for agricultural +purposes. Since that day the Sand Ridge has been famous as a +dry-farm district, and Major J. W. Powell, who saw the ripened +fields of grain in the hot dry sand, was moved upon to make special +mention of them in his volume on the "Arid Lands of Utah," published +in 1879. + +About this time, perhaps a year or two later, Joshua Salisbury and +George L. Farrell began dry-farm experiments in the famous Cache +Valley, one hundred miles north of Salt Lake City. After some years +of experimentation, with numerous failures these and other pioneers +established the practice of dry-farming in Cache Valley, which at +present is one of the most famous dry-farm sections in the United +States. In Tooele County, Just south of Salt Lake City, dry-farming +was practiced in 1877--how much earlier is not known. In the +northern Utah counties dry-farming assumed proportions of +consequence only in the later '70's and early '80's. During the +'80's it became a thoroughly established and extensive business +practice in the northern part of the state. + +California, which was settled soon after Utah, began dry-farm +experiments a little later than Utah. The available information +indicates that the first farming without irrigation in California +began in the districts of somewhat high precipitation. As the +population increased, the practice was pushed away from the +mountains towards the regions of more limited rainfall. According to +Hilgard, successful dry-farming on an extensive scale has been +practiced in California since about 1868. Olin reports that +moisture-saving methods were used on the Californian farms as early +as 1861. Certainly, California was a close second in originating +dry-farming. + +The Columbia Basin was settled by Mareus Whitman near Walla Walla in +1836, but farming did not gain much headway until the railroad +pushed through the great Northwest about 1880. Those familiar with +the history of the state of Washington declare that dry-farming was +in successful operation in isolated districts in the late '70's. By +1890 it was a well-established practice, but received a serious +setback by the financial panic of 1892-1893. Really successful and +extensive dry-farming in the Columbia Basin began about 1897. The +practice of summer fallow had begun a year or two before. It is +interesting to note that both in California and Washington there are +districts in which dry-farming has been practiced successfully under +a precipitation of about ten inches whereas in Utah the limit has +been more nearly twelve inches. + +In the Great Plains area the history of dry-farming Is hopelessly +lost in the greater history of the development of the eastern and +more humid parts of that section of the country. The great influx of +settlers on the western slope of the Great Plains area occurred in +the early '80's and overflowed into eastern Colorado and Wyoming a +few years later. The settlers of this region brought with them the +methods of humid agriculture and because of the relatively high +precipitation were not forced into the careful methods of moisture +conservation that had been forced upon Utah, California, and the +Columbia Basin. Consequently, more failures in dry-farming are +reported from those early days in the Great Plains area than from +the drier sections of the far West Dry-farming was practiced very +successfully in the Great Plains area during the later '80's. +According to Payne, the crops of 1889 were very good; in 1890, less +so; in 1891, better; in 1892 such immense crops were raised that the +settlers spoke of the section as God's country; in 1893, there was a +partial failure, and in 1894 the famous complete failure, which was +followed in 1895 by a partial failure. Since that time fair crops +have been produced annually. The dry years of 1893-1895 drove most +of the discouraged settlers back to humid sections and delayed, by +many years, the settlement and development of the western side of +the Great Plains area. That these failures and discouragements were +due almost entirely to improper methods of soil culture is very +evident to the present day student of dry-farming. In fact, from the +very heart of the section which was abandoned in 1893-1895 come +reliable records, dating back to 1886, which show successful crop +production every year. The famous Indian Head experimental farm of +Saskatchewan, at the north end of the Great Plains area, has an +unbroken record of good crop yields from 1888, and the early '90's +were quite as dry there as farther south. However, in spite of the +vicissitudes of the section, dry-farming has taken a firm hold upon +the Great Plains area and is now a well-established practice. + +The curious thing about the development of dry-farming in Utah, +California, Washington, and the Great Plains is that these four +sections appear to have originated dry-farming independently of each +other. True, there was considerable communication from 1849 onward +between Utah and California, and there is a possibility that some of +the many Utah settlers who located in California brought with them +accounts of the methods of dry-farming as practiced in Utah. This, +however, cannot be authenticated. It is very unlikely that the +farmers of Washington learned dry-farming from their California or +Utah neighbors, for until 1880 communication between Washington and +the colonies in California and Utah was very difficult, though, of +course, there was always the possibility of accounts of agricultural +methods being carried from place to place by the moving emigrants. +It is fairly certain that the Great Plains area did not draw upon +the far West for dry-farm methods. The climatic conditions are +considerably different and the Great Plains people always considered +themselves as living in a very humid country as compared with the +states of the far West. It may be concluded, therefore, that there +were four independent pioneers in dry-farming in United States. +Moreover, hundreds, probably thousands, of individual farmers over +the semiarid region have practiced dry-farming thirty to fifty years +with methods by themselves. + +Although these different dry-farm sections were developed +independently, yet the methods which they have finally adopted are +practically identical and include deep plowing, unless the subsoil +is very lifeless; fall plowing; the planting of fall grain wherever +fall plowing is possible; and clean summer fallowing. About 1895 the +word began to pass from mouth to mouth that probably nearly all the +lands in the great arid and semiarid sections of the United States +could be made to produce profitable crops without irrigation. At +first it was merely a whisper; then it was talked aloud, and before +long became the great topic of conversation among the thousands who +love the West and wish for its development. Soon it became a +National subject of discussion. Immediately after the close of the +nineteenth century the new awakening had been accomplished and +dry-farming was moving onward to conquer the waste places of the +earth. + +H. W. Campbell + +The history of the new awakening in dry-farming cannot well be +written without a brief account of the work of H. W. Campbell who, +in the public mind, has become intimately identified with the +dry-farm movement. H. W. Campbell came from Vermont to northern +South Dakota in 1879, where in 1882 he harvested a banner +crop,--twelve thousand bushels of wheat from three hundred acres. In +1883, on the same farm he failed completely. This experience led him +to a study of the conditions under which wheat and other crops may +be produced in the Great Plains area. A natural love for +investigation and a dogged persistence have led him to give his life +to a study of the agricultural problems of the Great Plains area. He +admits that his direct inspiration came from the work of Jethro +Tull, who labored two hundred years ago, and his disciples. He +conceived early the idea that if the soil were packed near the +bottom of the plow furrow, the moisture would be retained better and +greater crop certainty would result. For this purpose the first +subsurface packer was invented in 1885. Later, about 1895, when his +ideas had crystallized into theories, he appeared as the publisher +of Campbell's "Soil Culture and Farm Journal." One page of each +issue was devoted to a succinct statement of the "Campbell Method." +It was in 1898 that the doctrine of summer tillage was begun to be +investigated by him. + +In view of the crop failures of the early '90's and the gradual +dry-farm awakening of the later '90's, Campbell's work was received +with much interest. He soon became identified with the efforts of +the railroads to maintain demonstration farms for the benefit of +intending settlers. While Campbell has long been in the service of +the railroads of the semiarid region, yet it should be said in all +fairness that the railroads and Mr. Campbell have had for their +primary object the determination of methods whereby the farmers +could be made sure of successful crops. + +Mr. Campbell's doctrines of soil culture, based on his accumulated +experience, are presented in Campbell's "Soil Culture Manual," the +first edition of which appeared about 1904 and the latest edition, +considerably extended, was published in 1907. The 1907 manual is the +latest official word by Mr. Campbell on the principles and methods +of the "Campbell system." The essential features of the system may +be summarized as follows: The storage of water in the soil is +imperative for the production of crops in dry years. This may be +accomplished by proper tillage. Disk the land immediately after +harvest; follow as soon as possible with the plow; follow the plow +with the subsurface packer; and follow the packer with the smoothing +harrow. Disk the land again as early as possible in the spring and +stir the soil deeply and carefully after every rain. Sow thinly in +the fall with a drill. If the grain is too thick in the spring, +harrow it out. To make sure of a crop, the land should be "summer +tilled," which means that clean summer fallow should be practiced +every other year, or as often as may be necessary. + +These methods, with the exception of the subsurface packing, are +sound and in harmony with the experience of the great dry-farm +sections and with the principles that are being developed by +scientific investigation. The "Campbell system" as it stands to-day +is not the system first advocated by him. For instance, in the +beginning of his work he advocated sowing grain in April and in rows +so far apart that spring tooth harrows could be used for cultivating +between the rows. This method, though successful in conserving +moisture, is too expensive and is therefore superseded by the +present methods. Moreover, his farm paper of 1896, containing a full +statement of the "Campbell method," makes absolutely no mention of +"summer tillage," which is now the very keystone of the system. +These and other facts make it evident that Mr. Campbell has very +properly modified his methods to harmonize with the best experience, +but also invalidate the claim that he is the author of the dry-farm +system. A weakness of the "Campbell system" is the continual +insistence upon the use of the subsurface packer. As has already +been shown, subsurface packing is of questionable value for +successful crop production, and if valuable, the results may be much +more easily and successfully obtained by the use of the disk and +harrow and other similar implements now on the market. Perhaps the +one great weakness in the work of Campbell is that he has not +explained the principles underlying his practices. His publications +only hint at the reasons. H. W. Campbell, however, has done much to +popularize the subject of dry-farming and to prepare the way for +others. His persistence in his work of gathering facts, writing, and +speaking has done much to awaken interest in dry-farming. He has +been as "a voice in the wilderness" who has done much to make +possible the later and more systematic study of dry-farming. High +honor should be shown him for his faith in the semiarid region, for +his keen observation, and his persistence in the face of +difficulties. He is justly entitled to be ranked as one of the great +workers in behalf of the reclamation, without irrigation, of the +rainless sections of the world. + +The experiment stations + +The brave pioneers who fought the relentless dryness of the Great +American Desert from the memorable entrance of the Mormon pioneers +into the valley of the Great Salt Lake in 1847 were not the only +ones engaged in preparing the way for the present day of great +agricultural endeavor. Other, though perhaps more indirect, forces +were also at work for the future development of the semiarid +section. The Morrill Bill of 1862, making it possible for +agricultural colleges to be created in the various states and +territories, indicated the beginning of a public feeling that modern +methods should be applied to the work of the farm. The passage in +1887 of the Hatch Act, creating agricultural experiment stations in +all of the states and territories, finally initiated a new +agricultural era in the United States. With the passage of this +bill, stations for the application of modern science to crop +production were for the first time authorized in the regions of +limited rainfall, with the exception of the station connected with +the University of California, where Hilgard from 1872 had been +laboring in the face of great difficulties upon the agricultural +problems of the state of California. During the first few years of +their existence, the stations were busy finding men and problems. +The problems nearest at hand were those that had been attacked by +the older stations founded under an abundant rainfall and which +could not be of vital interest to arid countries. The western +stations soon began to attack their more immediate problems, and it +was not long before the question of producing crops without +irrigation on the great unirrigated stretches of the West was +discussed among the station staffs and plans were projected for a +study of the methods of conquering the desert. + +The Colorado Station was the first to declare its good intentions in +the matter of dry-farming, by inaugurating definite experiments. By +the action of the State Legislature of 1893, during the time of the +great drouth, a substation was established at Cheyenne Wells, near +the west border of the state and within the foothills of the Great +Plains area. From the summer of 1894 until 1900 experiments were +conducted on this farm. The experiments were not based upon any +definite theory of reclamation, and consequently the work consisted +largely of the comparison of varieties, when soil treatment was the +all-important problem to be investigated. True in 1898, a trial of +the "Campbell method" was undertaken. By the time this Station had +passed its pioneer period and was ready to enter upon more +systematic investigation, it was closed. Bulletin 59 of the Colorado +Station, published in 1900 by J. E. Payne, gives a summary of +observations made on the Cheyenne Wells substation during seven +years. This bulletin is the first to deal primarily with the +experimental work relating to dry-farming in the Great Plains area. +It does not propose or outline any system of reclamation. Several +later publications of the Colorado Station deal with the problems +peculiar to the Great Plains. + +At the Utah Station the possible conquest of the sagebrush deserts +of the Great Basin without irrigation was a topic of common +conversation during the years 1894 and 1895. In 1896 plans were +presented for experiments on the principles of dry-farming. Four +years later these plans were carried into effect. In the summer of +1901, the author and L. A. Merrill investigated carefully the +practices of the dry-farms of the state. On the basis of these +observations and by the use of the established principles of the +relation of water to soils and plants, a theory of dry-farming was +worked out which was published in Bulletin 75 of the Utah Station in +January, 1902. This is probably the first systematic presentation of +the principles of dry-farming. A year later the Legislature of the +state of Utah made provision for the establishment and maintenance +of six experimental dry-farms to investigate in different parts of +the state the possibility of dry-farming and the principles +underlying the art. These stations, which are still maintained, have +done much to stimulate the growth of dry-farming in Utah. The credit +of first undertaking and maintaining systematic experimental work in +behalf of dry-farming should be assigned to the state of Utah. Since +dry-farm experiments began in Utah in 1901, the subject has been a +leading one in the Station and the College. A large number of men +trained at the Utah Station and College have gone out as +investigators of dry-farming under state and Federal direction. + +The other experiment stations in the arid and semi-arid region were +not slow to take up the work for their respective states. Fortier +and Linfield, who had spent a number of years in Utah and had become +somewhat familiar with the dry-farm practices of that state, +initiated dry-farm investigations in Montana, which have been +prosecuted with great vigor since that time. Vernon, under the +direction of Foster, who had spent four years in Utah as Director of +the Utah Station, initiated the work in New Mexico. In Wyoming the +experimental study of dry-farm lands began by the private enterprise +of H. B. Henderson and his associates. Later V. T. Cooke was placed +in charge of the work under state auspices, and the demonstration of +the feasibility of dry-farming in Wyoming has been going on since +about 1907. Idaho has also recently undertaken dry-farm +investigations. Nevada, once looked upon as the only state in the +Union incapable of producing crops without irrigation, is +demonstrating by means of state appropriations that large areas +there are suitable for dry-farming. In Arizona, small tracts in this +sun-baked state are shown to be suitable for dry-farm lands. The +Washington Station is investigating the problems of dry-farming +peculiar to the Columbia Basin, and the staff of the Oregon Station +is carrying on similar work. In Nebraska, some very important +experiments dry-farming are being conducted. In North Dakota there +were in 1910 twenty-one dry-farm demonstration farms. In South +Dakota, Kansas, and Texas, provisions are similarly made for +dry-farm investigations. In fact, up and down the Great Plains area +there are stations maintained by the state or Federal government for +the purpose of determining the methods under which crops can be +produced without irrigation. + +At the head of the Great Plains area at Saskatchewan one of the +oldest dry-farm stations in America is located (since 1888). In +Russia several stations are devoted very largely to the problems of +dry land agriculture. To be especially mentioned for the excellence +of the work done are the stations at Odessa, Cherson, and Poltava. +This last-named Station has been established since 1886. + +In connection with the work done by the experiment stations should +be mentioned the assistance given by the railroads. Many of the +railroads owning land along their respective lines are greatly +benefited in the selling of these lands by a knowledge of the +methods whereby the lands may be made productive. However, the +railroads depend chiefly for their success upon the increased +prosperity of the population along their lines and for the purpose +of assisting the settlers in the arid West considerable sums have +been expended by the railroads in cooperation with the stations for +the gathering of information of value in the reclamation of arid +lands without irrigation. + +It is through the efforts of the experiment stations that the +knowledge of the day has been reduced to a science of dry-farming. +Every student of the subject admits that much is yet to be learned +before the last word has been said concerning the methods of +dry-farming in reclaiming the waste places of the earth. The future +of dry-farming rests almost wholly upon the energy and intelligence +with which the experiment stations in this and other countries of +the world shall attack the special problems connected with this +branch of agriculture. + +The United States Department of Agriculture + +The Commissioner of Agriculture of the United States was given a +secretaryship in the President's Cabinet in 1889. With this added +dignity, new life was given to the department. Under the direction +of J. Sterling Morton preliminary work of great importance was done. +Upon the appointment of James Wilson as Secretary of Agriculture, +the department fairly leaped into a fullness of organization for the +investigation of the agricultural problems of the country. From the +beginning of its new growth the United States Department of +Agriculture has given some thought to the special problems of the +semiarid region, especially that part within the Great Plains. +Little consideration was at first given to the far West. The first +method adopted to assist the farmers of the plains was to find +plants with drouth resistant properties. For that purpose explorers +were sent over the earth, who returned with great numbers of new +plants or varieties of old plants, some of which, such as the durum +wheats, have shown themselves of great value in American +agriculture. The Bureaus of Plant Industry, Soils, Weather, and +Chemistry have all from the first given considerable attention to +the problems of the arid region. The Weather Bureau, long +established and with perfected methods, has been invaluable in +guiding investigators into regions where experiments could be +undertaken with some hope of success. The Department of Agriculture +was somewhat slow, however, in recognizing dry-farming as a system +of agriculture requiring special investigation. The final +recognition of the subject came with the appointment, in 1905, of +Chilcott as expert in charge of dry-land investigations. At the +present time an office of dry-land investigations has been +established under the Bureau of Plant Industry, which cooperates +with a number of other divisions of the Bureau in the investigation +of the conditions and methods of dry-farming. A large number of +stations are maintained by the Department over the arid and semiarid +area for the purpose of studying special problems, many of which are +maintained in connection with the state experiment stations. Nearly +all the departmental experts engaged in dry-farm investigation have +been drawn from the service of the state stations and in these +stations had received their special training for their work. The +United States Department of Agriculture has chosen to adopt a strong +conservatism in the matter of dry-farming. It may be wise for the +Department, as the official head of the agricultural interests of +the country, to use extreme care in advocating the settlement of a +region in which, in the past, farmers had failed to make a living, +yet this conservatism has tended to hinder the advancement of +dry-farming and has placed the departmental investigations of +dry-farming in point of time behind the pioneer investigations of +the subject. + +The Dry-farming Congress + +As the great dry-farm wave swept over the country, the need was felt +on the part of experts and laymen of some means whereby dry-farm +ideas from all parts of the country could be exchanged. Private +individuals by the thousands and numerous state and governmental +stations were working separately and seldom had a chance of +comparing notes and discussing problems. A need was felt for some +central dry-farm organization. An attempt to fill this need was made +by the people of Denver, Colorado, when Governor Jesse F. McDonald +of Colorado issued a call for the first Dry-farming Congress to be +held in Denver, January 24, 25, and 26, 1907. These dates were those +of the annual stock show which had become a permanent institution of +Denver and, in fact, some of those who were instrumental in the +calling of the Dry-farming Congress thought that it was a good +scheme to bring more people to the stock show. To the surprise of +many the Dry-farming Congress became the leading feature of the +week. Representatives were present from practically all the states +interested in dry-farming and from some of the humid states. Utah, +the pioneer dry-farm state, was represented by a delegation second +in size only to that of Colorado, where the Congress was held. The +call for this Congress was inspired, in part at least, by real +estate men, who saw in the dry-farm movement an opportunity to +relieve themselves of large areas of cheap land at fairly good +prices. The Congress proved, however, to be a businesslike meeting +which took hold of the questions in earnest, and from the very first +made it clear that the real estate agent was not a welcome member +unless he came with perfectly honest methods. + +The second Dry-farming Congress was held January 22 to 25, 1908, in +Salt Lake City, Utah, under the presidency of Fisher Harris. It was +even better attended than the first. The proceedings show that it +was a Congress at which the dry-farm experts of the country stated +their findings. A large exhibit of dry-farm products was held in +connection with this Congress, where ocular demonstrations of the +possibility of dry-farming were given any doubting Thomas. + +The third Dry-farming Congress was held February 23 to 25, 1909, at +Cheyenne, Wyoming, under the presidency of Governor W. W. Brooks of +Wyoming. An unusually severe snowstorm preceded the Congress, which +prevented many from attending, yet the number present exceeded that +at any of the preceding Congresses. This Congress was made notable +by the number of foreign delegates who had been sent by their +respective countries to investigate the methods pursued in America +for the reclamation of the arid districts. Among these delegates +were representatives from Canada, Australia, The Transvaal, Brazil, +and Russia. + +The fourth Congress was held October 26 to 28, 1909, in Billings, +Montana, under the presidency of Governor Edwin L. Morris of +Montana. The uncertain weather of the winter months had led the +previous Congress to adopt a time in the autumn as the date of the +annual meeting. This Congress became a session at which many of the +principles discussed during the three preceding Congresses were +crystallized into definite statements and agreed upon by workers +from various parts of the country. A number of foreign +representatives were present again. The problems of the Northwest +and Canada were given special attention. The attendance was larger +than at any of the preceding Congresses. + +The fifth Congress will be held under the presidency of Hon. F. W. +Mondell of Wyoming at Spokane, Washington, during October, 1910. It +promises to exceed any preceding Congress in attendance and +interest. + +The Dry-farming Congress has made itself one of the most important +factors in the development of methods for the reclamation of the +desert. Its published reports are the most valuable publications +dealing with dry-land agriculture. Only simple justice is done when +it is stated that the success of the Dry-farming Congress is due in +a large measure to the untiring and intelligent efforts of John T. +Burns, who is the permanent secretary of the Congress, and who was a +member of the first executive committee. + +Nearly all the arid and semiarid states have organized state +dry-farming congresses. The first of these was the Utah Dry-farming +Congress, organized about two months after the first Congress held +in Denver. The president is L. A. Merrill, one of the pioneer +dry-farm investigators of the Rockies. + +Jethro Tull (see frontispiece) + +A sketch of the history of dry-farming would be incomplete without a +mention of the life and work of Jethro Tull. The agricultural +doctrines of this man, interpreted in the light of modern science, +are those which underlie modern dry-farming. Jethro Tull was born in +Berkshire, England, 1674, and died in 1741. He was a lawyer by +profession, but his health was so poor that he could not practice +his profession and therefore spent most of his life in the seclusion +of a quiet farm. His life work was done in the face of great +physical sufferings. In spite of physical infirmities, he produced a +system of agriculture which, viewed in the light of our modern +knowledge, is little short of marvelous. The chief inspiration of +his system came from a visit paid to south of France, where he +observed "near Frontignan and Setts, Languedoc" that the vineyards +were carefully plowed and tilled in order to produce the largest +crops of the best grapes. Upon the basis of this observation he +instituted experiments upon his own farm and finally developed his +system, which may be summarized as follows: The amount of seed to be +used should be proportional to the condition of the land, especially +to the moisture that is in it. To make the germination certain, the +seed should be sown by drill methods. Tull, as has already been +observed, was the inventor of the seed drill which is now a feature +of all modern agriculture. Plowing should be done deeply and +frequently; two plowings for one crop would do no injury and +frequently would result in an increased yield. Finally, as the most +important principle of the system, the soil should be cultivated +continually, the argument being that by continuous cultivation the +fertility of the soil would be increased, the water would be +conserved, and as the soil became more fertile less water would be +used. To accomplish such cultivation, all crops should be placed in +rows rather far apart, so far indeed that a horse carrying a +cultivator could walk between them. The horse-hoeing idea of the +system became fundamental and gave the name to his famous book, "The +Horse Hoeing Husbandry," by Jethro Tull, published in parts from +1731 to 1741. Tull held that the soil between the rows was +essentially being fallowed and that the next year the seed could be +planted between the rows of the preceding year and in that way the +fertility could be maintained almost indefinitely. If this method +were not followed, half of the soil could lie fallow every other +year and be subjected to continuous cultivation. Weeds consume water +and fertility and, therefore, fallowing and all the culture must be +perfectly clean. To maintain fertility a rotation of crops should be +practiced. Wheat should be the main grain crop; turnips the root +crop; and alfalfa a very desirable crop. + +It may be observed that these teachings are sound and in harmony +with the best knowledge of to-day and that they are the very +practices which are now being advocated in all dry-farm sections. +This is doubly curious because Tull lived in a humid country. +However, it may be mentioned that his farm consisted of a very poor +chalk soil, so that the conditions under which he labored were more +nearly those of an arid country than could ordinarily be found in a +country of abundant rainfall. While the practices of Jethro Tull +were in themselves very good and in general can be adopted to-day, +yet his interpretation of the principles involved was wrong. In view +of the limited knowledge of his day, this was only to be expected. +For instance, he believed so thoroughly in the value of cultivation +of the soil, that he thought it would take the place of all other +methods of maintaining soil-fertility. In fact, he declared +distinctly that "tillage is manure," which we are very certain at +this time is fallacious. Jethro Tull is one of the great +investigators of the world. In recognition of the fact that, though +living two hundred years ago in a humid country, he was able to +develop the fundamental practices of soil culture now used in +dry-farming, the honor has been done his memory of placing his +portrait as the frontispiece of this volume. + + + + + + +CHAPTER XX + +DRY-FARMING IN A NUTSHELL + + + + + +Locate the dry-farm in a section with an annual precipitation of +more than ten inches and, if possible, with small wind movement. One +man with four horses and plenty of machinery cannot handle more than +from 160 to 200 acres. Farm fewer acres and farm them better. + +Select a clay loam soil. Other soils may be equally productive, but +are cultivated properly with somewhat more difficulty. + +Make sure, with the help of the soil auger, that the soil is of +uniform structure to a depth of at least eight feet. If streaks of +loose gravel or layers of hardpan are near the surface, water may be +lost to the plant roots. + +After the land has been cleared and broken let it lie fallow with +clean cultivation, for one year. The increase in the first and later +crops will pay for the waiting. + +Always plow the land early in the fall, unless abundant experience +shows that fall plowing is an unwise practice in the locality. +Always plow deeply unless the subsoil is infertile, in which case +plow a little deeper each year until eight or ten inches are reached +Plow at least once for each crop. Spring plowing; if practiced, +should be done as early as possible in the season. + +Follow the plow, whether in the fall or spring, with the disk and +that with the smoothing harrow, if crops are to be sown soon +afterward. If the land plowed in the fall is to lie fallow for the +winter, leave it in the rough condition, except in localities where +there is little or no snow and the winter temperature is high. + +Always disk the land in early spring, to prevent evaporation. Follow +the disk with the harrow. Harrow, or in some other way stir the +surface of the soil after every rain. If crops are on the land, +harrow as long as the plants will stand it. If hoed crops, like corn +or potatoes, are grown, use the cultivator throughout the season. A +deep mulch or dry soil should cover the land as far as possible +throughout the summer. Immediately after harvest disk the soil +thoroughly. + +Destroy weeds as soon as they show themselves. A weedy dry-farm is +doomed to failure. + +Give the land an occasional rest, that is, a clean summer fallow. +Under a rainfall of less than fifteen inches, the land should be +summer fallowed every other year; under an annual rainfall of +fifteen to twenty inches, the summer fallow should occur every third +or fourth year. Where the rainfall comes chiefly in the summer, the +summer fallow is less important in ordinary years than where the +summers are dry and the winters wet. Only an absolutely clean fallow +should be permitted. + +The fertility of dry-farm soils must be maintained. Return the +manure; plow under green leguminous crops occasionally and practice +rotation. On fertile soils plants mature with the least water. + +Sow only by the drill method. Wherever possible use fall varieties +of crops. Plant deeply--three or four inches for grain. Plant early +in the fall, especially if the land has been summer fallowed. Use +only about one half as much seed as is recommended for +humid-farming. + +All the ordinary crops may be grown by dry-farming. Secure seed that +has been raised on dry-farms. Look out for new varieties, especially +adapted for dry-farming, that may be brought in. Wheat is king in +dry-farming; corn a close second. Turkey wheat promises the best. + +Stock the dry-farm with the best modern machinery. Dry-farming is +possible only because of the modern plow, the disk, the drill +seeder, the harvester, the header, and the thresher. + +Make a home on the dry-farm. Store the flood waters in a reservoir; +or pump the underground waters, for irrigating the family garden. +Set out trees, plant flowers, and keep some live stock. + +Learn to understand the reasons back of the principles of +dry-farming, apply the knowledge vigorously, and the crop cannot +fail. + +Always farm as if a year of drouth were coming. + +Man, by his intelligence, compels the laws of nature to do his +bidding, and thus he achieves joy. + +"And God blessed them--and God said unto them, Be fruitful and +multiply and replenish the earth, and subdue it." + + + + + + +CHAPTER XIX + +THE YEAR OF DROUTH + + + + + +The Shadow of the Year of Drouth still obscures the hope of many a +dry-farmer. From the magazine page and the public platform the +prophet of evil, thinking himself a friend of humanity, solemnly +warns against the arid region and dry-farming, for the year of +drouth, he says, is sure to come again and then will be repeated the +disasters of 1893-1895. Beware of the year of drouth. Even +successful dry-farmers who have obtained good crops every year for a +generation or more are half led to expect a dry year or one so dry +that crops will fail in spite of all human effort. The question is +continually asked, "Can crop yields reasonably be expected every +year, through a succession of dry years, under semiarid conditions, +if the best methods of dry-farming be practiced?" In answering this +question, it may be said at the very beginning, that when the year +of drouth is mentioned in connection with dry-farming, sad reference +is always made to the experience on the Great Plains in the early +years of the '90's. Now the fact of the matter is, that while the +years of 1893,1894, and 1895 were dry years, the only complete +failure came in 1894. In spite of the improper methods practiced by +the settlers, the willing soil failed to yield a crop only one year. +Moreover, it should not be forgotten that hundreds of farmers in the +driest section during this dry period, who instinctively or +otherwise farmed more nearly right, obtained good crops even in +1894. The simple practice of summer fallowing, had it been practiced +the year before, would have insured satisfactory crops in the driest +year. Further, the settlers who did not take to their heels upon the +arrival of the dry year are still living in large numbers on their +homesteads and in numerous instances have accumulated comfortable +fortunes from the land which has been held up so long as a warning +against settlement beyond a humid climate. The failure of 1894 was +due as much to a lack of proper agricultural information and +practice as to the occurrence of a dry year. + +Next, the statement is carelessly made that the recent success in +dry-farming is due to the fact that we are now living in a cycle of +wet years, but that as soon as the cycle of dry years strikes the +country dry-farming will vanish as a dismal failure. Then, again, +the theory is proposed that the climate is permanently changing +toward wetness or dryness and the past has no meaning in reading the +riddle of the future. It is doubtless true that no man may safely +predict the weather for future generations; yet, so far as human +knowledge goes, there is no perceptible average change in the +climate from period to period within historical time; neither are +there protracted dry periods followed by protracted wet periods. The +fact is, dry and wet years alternate. A succession of somewhat wet +years may alternate with a succession of somewhat dry years, but the +average precipitation from decade to decade is very nearly the same. +True, there will always be a dry year, that is, the driest year of a +series of years, and this is the supposedly fearful and fateful year +of drouth. The business of the dry-farmer is always to farm so as to +be prepared for this driest year whenever it comes. If this be done, +the farmer will always have a crop: in the wet years his crop will +be large; in the driest year it will be sufficient to sustain him. + +So persistent is the half-expressed fear that this driest year makes +it impossible to rely upon dry-farming as a permanent system of +agriculture that a search has been made for reliable long records of +the production of crops in arid and semiarid regions. Public +statements have been made by many perfectly reliable men to the +effect that crops have been produced in diverse sections over long +periods of years, some as long as thirty-five or forty year's, +without one failure having occurred. Most of these statements, +however, have been general in their nature and not accompanied by +the exact yields from year to year. Only three satisfactory records +have been found in a somewhat careful search. Others no doubt exist. + +The first record was made by Senator J. G. M. Barnes of Kaysville, +Utah. Kaysville is located in the Great Salt Lake Valley, about +fifteen miles north of Salt Lake City. The climate is semiarid; the +precipitation comes mainly in the winter and early spring; the +summers are dry, and the evaporation is large. Senator Barnes +purchased ninety acres of land in the spring of 1887 and had it +farmed under his own supervision until 1906. He is engaged in +commercial enterprises and did not, himself, do any of the work on +the farm, but employed men to do the necessary labor. However, he +kept a close supervision of the farm and decided upon the practices +which should be followed. From seventy-eight to eighty-nine acres +were harvested for each crop, with the exception of 1902, when all +but about twenty acres was fired by sparks from the passing railroad +train. The plowing, harrowing, and weeding were done very carefully. +The complete record of the Barnes dry-farm from 1887 to 1905 is +shown in the table on the following page. + + +Record of the Barnes Dry-farm, Salt Lake Valley, Utah (90 acres) + +Year Annual Yield When When + Rainfall per Acre Plowed Sown + (Inches) (Bu.) +1887 11.66 --- May Sept. +1888 13.62 Failure May Sept. +1889 18.46 22.5 --- Volunteer+ +1890 10.38 15.5 --- --- +1891 15.92 Fallow May Fall +1892 14.08 19.3 --- --- +1893 17.35 Fallow May Fall +1894 15.27 26.0 --- --- +1895 11.95 Fallow May Aug. +1896 18.42 22.0 --- --- +1897 16.74 Fallow Spring Fall +1898 16.09 26.0 --- --- +1899 17.57 Fallow May Fall +1900 11.53 23.5 --- --- +1901 16.08 Fallow Spring Fall +1902 11.41 28.9 Sept. Fall +1903 14.62 12.5 --- --- +1904 16.31 Fallow Spring Fall +1905 14.23 25.8 --- --- + ++About four acres were sown on stubble. + + +The first plowing was given the farm in May of 1887, and, with the +exception of 1902, the land was invariably plowed in the spring. +With fall plowing the yields would undoubtedly have been better. The +first sowing was made in the fall of 1887, and fall grain was grown +during the whole period of observation. The seed sown in the fall of +1887 came up well, but was winter-killed. This is ascribed by +Senator Barnes to the very dry winter, though it is probable that +the soil was not sufficiently well stored with moisture to carry the +crop through. The farm was plowed again in the spring of 1888, and +another crop sown in September of the same year. In the summer of +1889, 22-1/2 bushels of wheat were harvested to the acre. Encouraged +by this good crop Mr. Barnes allowed a volunteer crop to grow that +fall and the next summer harvested as a result 15-1/2 bushels of +wheat to the acre. The table shows that only one crop smaller than +this was harvested during the whole period of nineteen years, +namely, in 1903, when the same thing was done, and one crop was made +to follow another without an intervening fallow period. This +observation is an evidence in favor of clean summer fallowing. The +largest crop obtained, 28.9 bushels per acre in 1902, was gathered +in a year when the next to the lowest rainfall of the whole period +occurred, namely, 11.41 inches. + +The precipitation varied during the nineteen years from 10.33 inches +to 18.46 inches. The variation in yield per acre was considerably +less than this, not counting the two crops that were grown +immediately after another crop. All in all, the unique record of the +Barnes dry-farm shows that through a period of nineteen years, +including dry and comparatively wet years, there was absolutely no +sign of failure, except in the first year, when probably the soil +had not been put in proper condition to support crops. In passing it +maybe mentioned that, according to the records furnished by Senator +Barnes, the total cost of operating the farm during the nineteen +years was $4887.69; the total income was $10,144.83. The difference, +$5257.14, is a very fair profit on the investment of $1800--the +original cost of the farm. + +The Indian Head farm + +An equally instructive record is furnished by the experimental farm +located at Indian Head in Saskatchewan, Canada, in the northern part +of the Great Plains area. According to Alway, the country is in +appearance very much like western Nebraska and Kansas; the climate +is distinctly arid, and the precipitation comes mainly in the spring +and summer. It is the only experimental dry-farm in the Great Plains +area with records that go back before the dry years of the early +'90's. In 1882 the soil of this farm was broken, and it was farmed +continuously until 1888, when it was made an experimental farm under +government supervision. The following table shows the yields +obtained from the year 1891, when the precipitation records were +first kept, to 1909:-- + +RECORD OF INDIAN HEAD EXPERIMENTAL FARM AND MOTHERWELL'S FARM, +SASKATCHEWAN, CANADA + +Year Annual Bushels of Wheat Bushels of Wheat Bushels of Wheat + Rainfall per Acre per Acre per Acre + (Inches)+ Experimental Experimental Motherwell's Farm + Farm--Fallow Farm--Stubble +1891 14.03 35 32 30 +1892 6.92 28 21 28 +1893 10.11 35 22 34 +1894 3.90 17 9 24 +1895 12.28 41 22 26 +1896 10.59 39 29 31 +1897 14.62 33 26 35 +1898 18.03 32 --- 27 +1899 9.44 33 --- 33 +1900 11.74 17 5 25 +1901 20.22 49 38 51 +1902 10.73 38 22 28 +1903 15.55 35 15 31 +1904 11.96 40 29 35 +1905 19.17 42 18 36 +1906 13.21 26 13 38 +1907 15.03 18 18 15 +1908 13.17 29 14 16 +1909 13.96 28 15 23 + ++Snowfall not included. This has varied from 2.3 to 1.3 inches of water. + + +The annual rainfall shown in the second column does not include the +water which fell in the form of snow. According to the records at +hand, the annual snow fall varied from 2.3 to 1.3 inches of water, +which should be added to the rainfall given in the table. Even with +this addition the rainfall shows the district to be of a distinctly +semiarid character. It will be observed that the precipitation +varied from 3.9 to 20.22 inches, and that during the early '90's +several rather dry years occurred. In spite of this large variation +good crops have been obtained during the whole period of nineteen +years. Not one failure is recorded. The lowest yield of 17 bushels +per acre came during the very dry year of 1894 and during the +somewhat dry year of 1900. Some of the largest yields were obtained +in seasons when the rainfall was only near the average. As a record +showing that the year of drouth need not be feared when dry-farming +is done right, this table is of very high interest. It may be noted, +incidentally, that throughout the whole period wheat following a +fallow always yielded higher than wheat following the stubble. For +the nineteen years, the difference was as 32.4 bushels is to 20.5 +bushels. + +The Mother well farm + +In the last column of the table are shown the annual yields of wheat +obtained on the farm of Commissioner Motherwell of the province of +Saskatchewan. This private farm is located some twenty-five miles +away from Indian Head, and the rainfall records of the experimental +farm are, therefore, only approximately accurate for the Motherwell +farm. The results on this farm may well be compared to the Barnes +results of Utah, since they were obtained on a private farm. During +the period of nineteen years good crops were invariably obtained; +even during the very dry year of 1894, a yield of twenty-four +bushels of wheat to the acre was obtained. Curiously enough, the +lowest yields of fifteen and sixteen bushels to the acre were +obtained in 1907 and 1908 when the precipitation was fairly good, +and must be ascribed to some other factor than that of +precipitation. The record of this farm shows conclusively that with +proper farming there is no need to fear the year of drouth. + +The Utah drouth of 1910 + +During the year of 1910 only 2.7 inches of rain fell in Salt Lake +City from March 1 to the July harvest, and all of this in March, as +against 7.18 inches during the same period the preceding year. In +other parts of the state much less rain fell; in fact, in the +southern part of the state the last rain fell during the last week +of December, 1909. The drouth remained unbroken until long after the +wheat harvests. Great fear was expressed that the dry-farms could +not survive so protracted a period of drouth. Agents, sent out over +the various dry-farm districts, reported late in June that wherever +clean summer fallowing had been practiced the crops were in +excellent condition; but that wherever careless methods had been +practiced, the crops were poor or killed. The reports of the harvest +in July of 1910 showed that fully 85 per cent of an average crop was +obtained in spite of the protracted drouth wherever the soil came +into the spring well stored with moisture, and in many instances +full crops were obtained. + +Over the whole of the dry-farm territory of the United States +similar conditions of drouth occurred. After the harvest, however, +every state reported that the crops were well up to the average +wherever correct methods of culture had been employed. + +These well-authenticated records from true semi-arid districts, +covering the two chief types of winter and summer precipitation, +prove that the year of drouth, or the driest year in a twenty-year +period, does not disturb agricultural conditions seriously in +localities where the average annual precipitation is not too low, +and where proper cultural methods arc followed. That dry-farming is +a system of agricultural practice which requires the application of +high skill and intelligence is admitted; that it is precarious is +denied. The year of drouth is ordinarily the year in which the man +failed to do properly his share of the work. + + + + + + +CHAPTER XVIII + +THE PRESENT STATUS OF DRY-FARMING + + + + + +It is difficult to obtain a correct view of the present status of +dry-farming, first, because dry-farm surveys are only beginning to +be made and, secondly, because the area under dry-farm cultivation +is increasing daily by leaps and bounds. All arid and semiarid parts +of the world are reaching out after methods of soil culture whereby +profitable crops may be produced without irrigation, and the +practice of dry-farming, according to modern methods, is now +followed in many diverse countries. The United States undoubtedly +leads at present in the area actually under dry-farming, but, in +view of the immense dry-farm districts in other parts of the world, +it is doubtful if the United States will always maintain its +supremacy in dry-farm acreage. The leadership in the development of +a science of dry-farming will probably remain with the United States +for years, since the numerous experiment stations established for +the study of the problems of farming without irrigation have their +work well under way, while, with the exception of one or two +stations in Russia and Canada, no other countries have experiment +stations for the study of dry-farming in full operation. The reports +of the Dry-farming Congress furnish practically the only general +information as to the status of dry-farming in the states and +territories of the United States and in the countries of the world. + +California + +In the state of California dry-farming has been firmly established +for more than a generation. The chief crop of the California +dry-farms is wheat, though the other grains, root crops, and +vegetables are also grown without irrigation under a comparatively +small rainfall. The chief dry-farm areas are found in the Sacramento +and the San Joaquin valleys. In the Sacramento Valley the +precipitation is fairly large, but in the San Joaquin Valley it is +very small. Some of the most successful dry-farms of California have +produced well for a long succession of years under a rainfall of ten +inches and less. California offers a splendid example of the great +danger that besets all dry-farm sections. For a generation wheat has +been produced on the fertile Californian soils without manuring of +any kind. As a consequence, the fertility of the soils has been so +far depleted that at present it is difficult to obtain paying crops +without irrigation on soils that formerly yielded bountifully. The +living problem of the dry-farms in California is the restoration of +the fertility which has been removed from the soils by unwise +cropping. All other dry-farm districts should take to heart this +lesson, for, though crops may be produced on fertile soils for one, +two, or even three generations without manuring, yet the time will +come when plant-food must be added to the soil in return for that +which has been removed by the crops. Meanwhile, California offers, +also, an excellent example of the possibility of successful +dry-farming through long periods and under varying climatic +conditions. In the Golden State dry-farming is a fully established +practice; it has long since passed the experimental stage. + +Columbia River Basin + +The Columbia River Basin includes the state of Washington, most of +Oregon, the northern and central part of Idaho, western Montana, and +extends into British Columbia. It includes the section often called +the Inland Empire, which alone covers some one hundred and fifty +thousand square miles. The chief dry-farm crop of this region is +wheat; in fact, western Washington or the "Palouse country" is +famous for its wheat-producing powers. The other grains, potatoes, +roots, and vegetables are also grown without irrigation. In the +parts of this dry-farm district where the rainfall is the highest, +fruits of many kinds and of a high quality are grown without +irrigation. It is estimated that at least two million acres are +being dry-farmed in this district. Dry-farming is fully established +in the Columbia River Basin. One farmer is reported to have raised +in one year on his own farm two hundred and fifty thousand bushels +of wheat. In one section of the district where the rainfall for the +last few years has been only about ten or eleven inches, wheat has +been produced successfully. This corroborates the experience of +California, that wheat may really be grown in localities where the +annual rainfall is not above ten inches. The most modern methods of +dry-farming are followed by the farmers of the Columbia River Basin, +but little attention has been given to soil-fertility, since soils +that have been farmed for a generation still appear to retain their +high productive powers. Undoubtedly, however, in this district, as +in California, the question of soil-fertility will be an important +one in the near future. This is one of the great dry-farm districts +of the world. + +The Great Basin + +The Great Basin includes Nevada, the western half of Utah, a small +part of southern Oregon and Idaho, and also a part of Southern +California. It is a great interior basin with all its rivers +draining into salt lakes or dry sinks. In recent geological times +the Great Basin was filled with water, forming the great Lake +Bonneville which drained into the Columbia River. In fact, the Great +Basin is made up of a series of great valleys, with very level +floors, representing the old lake bottom. On the bench lands are +seen, in many places, the effects of the wave action of the ancient +lake. The chief dry-farm crop of this district is wheat, but the +other grains, including corn, are also produced successfully. Other +crops have been tried with fair success, but not on a commercial +scale. Grapevines have been made to grow quite successfully without +irrigation on the bench lands. Several small orchards bearing +luscious fruit are growing on the deep soils of the Great Basin +without the artificial application of water. Though the first +dry-farming by modern peoples was probably practiced in the Great +Basin, yet the area at present under cultivation is not large, +possibly a little more than four hundred thousand acres. + +Dry-farming, however, is well established. There are large areas, +especially in Nevada, that receive less than ten inches of rainfall +annually, and one of the leading problems before the dry-farmers of +this district is the determination of the possibility of producing +crops upon such lands without irrigation. On the older dry-farms, +which have existed in some cases from forty to fifty years, there +are no signs of diminution of soil-fertility. Undoubtedly, however, +even under the conditions of extremely high fertility prevailing in +the Great Basin, the time will soon come when the dry-farmer must +make provision for restoring to the soil some of the fertility taken +away by crops. There are millions of acres in the Great Basin yet to +be taken up and subjected to the will of the dry-farmer. + +Colorado and Rio Grande River Basins + +The Colorado and Rio Grande River Basins include Arizona and the +western part of New Mexico. The chief dry-farm crops of this dry +district are wheat, corn, and beans. Other crops have also been +grown in small quantities and with some success. The area suitable +for dry-farming in this district has not yet been fully determined +and, therefore, the Arizona and New Mexico stations are undertaking +dry-farm surveys of their respective states. In spite of the fact +that Arizona is generally looked upon as one of the driest states of +the Union, dry-farming is making considerable headway there. In New +Mexico, five sixths of all the homestead applications during the +last year were for dry-farm lands; and, in fact, there are several +prosperous communities in New Mexico which are subsisting almost +wholly on dry-farming. It is only fair to say, however, that +dry-farming is not yet well established in this district, but that +the prospects are that the application of scientific principles will +soon make it possible to produce profitable crops without irrigation +in large parts of the Colorado and Rio Grande River Basins. + +The mountain states + +This district includes a part of Montana, nearly the whole of +Wyoming and Colorado, and part of eastern Idaho. It is located along +the backbone of the Rocky Mountains. The farms are located chiefly +in valleys and on large rolling table-lands. The chief dry-farm crop +is wheat, though the other crops which are grown elsewhere on +dry-farms may be grown here also. In Montana there is a very large +area of land which has been demonstrated to be well adapted for +dry-farm purposes. In Wyoming, especially on the eastern as well as +on the far western side, dry-farming has been shown to be +successful, but the area covered at the present time is +comparatively small. In Idaho, dry-farming is fairly well +established. In Colorado, likewise, the practice is very well +established and the area is tolerably large. All in all, throughout +the mountain states dry-farming may be said to be well established, +though there is a great opportunity for the extension of the +practice. The sparse population of the western states naturally +makes it impossible for more than a small fraction of the land to be +properly cultivated. + +The Great Plains Area + +This area includes parts of Montana, North Dakota, South Dakota, +Nebraska, Kansas, Wyoming, Colorado, New Mexico, Oklahoma, and +Texas. It is the largest area of dry-farm land under approximately +uniform conditions. Its drainage is into the Mississippi, and it +covers an area of not less than four hundred thousand square miles. +Dry-farm crops grow well over the whole area; in fact, dry-farming +is well established in this district. In spite of the failures so +widely advertised during the dry season of 1894, the farmers who +remained on their farms and since that time have employed modern +methods have secured wealth from their labors. The important +question before the farmers of this district is that of methods for +securing the best results. From the Dakotas to Texas the farmers +bear the testimony that wherever the soil has been treated right, +according to approved methods, there have been no crop failures. + +Canada + +Dry-farming has been pushed vigorously in the semiarid portions of +Canada, and with great success. Dry-farming is now reclaiming large +areas of formerly worthless land, especially in Alberta, +Saskatchewan, and the adjoining provinces. Dry-farming is +comparatively recent in Canada, yet here and there are semiarid +localities where crops have been raised without irrigation for +upwards of a quarter of a century. In Alberta and other places it +has been now practiced successfully for eight or ten years, and it +may be said that dry-farming is a well-established practice in the +semiarid regions of the Dominion of Canada. + +Mexico + +In Mexico, likewise, dry-farming has been tried and found to be +successful. The natives of Mexico have practiced farming without +irrigation for centuries--and modern methods are now being applied +in the zone midway between the extremely dry and the extremely humid +portions. The irregular distribution of the precipitation, the late +spring and early fall frosts, and the fierce winds combine to make +the dry-farm problem somewhat difficult, yet the prospects are that, +with government assistance, dry-farming in the near future will +become an established practice in Mexico. In the opinion of the best +students of Mexico it is the only method of agriculture that can be +made to reclaim a very large portion of the country. + +Brazil + +Brazil, which is greater in area than the United States, also has a +large arid and semiarid territory which can be reclaimed only by +dry-farm methods. Through the activity of leading citizens +experiments in behalf of the dry-farm movement have already been +ordered. The dry-farm district of Brazil receives an annual +precipitation of about twenty-five inches, but irregularly +distributed and under a tropical sun. In the opinion of those who +are familiar with the conditions the methods of dry-farming may be +so adapted as to make dry-farming successful in Brazil. + +Australia + +Australia, larger than the continental United States, is vitally +interested in dry-farming, for one third of its vast area is under a +rainfall of less than ten inches, and another third is under a +rainfall of between ten and twenty inches. Two thirds of the area of +Australia, if reclaimed at all, must be reclaimed by dry-farming. +The realization of this condition has led several Australians to +visit the United States for the purpose of learning the methods +employed in dry-farming. The reports on dry-farming in America by +Surveyor-General Strawbridge and Senator J. H. McColl have done much +to initiate a vigorous propaganda in behalf of dry-farming in +Australia. Investigation has shown that occasional farmers are found +in Australia, as in America, who have discovered for themselves many +of the methods of dry-farming and have succeeded in producing crops +profitably. Undoubtedly, in time, Australia will be one of the great +dry-farming countries of the world. + +Africa + +Up to the present, South Africa only has taken an active interest in +the dry-farm movement, due to the enthusiastic labors of Dr. William +Macdonald of the Transvaal. The Transvaal has an average annual +precipitation of twenty-three inches, with a large district that +receives between thirteen and twenty inches. The rain comes in the +summer, making the conditions similar to those of the Great Plains. +The success of dry-farming has already been practically +demonstrated. The question before the Transvaal farmers is the +determination of the best application of water conserving methods +under the prevailing conditions. Under proper leadership the +Transvaal and other portions of Africa will probably join the ranks +of the larger dry-farming countries of the world. + +Russia + +More than one fourth of the whole of Russia is so dry as to be +reclaimable only by dry-farming. The arid area of southern European +Russia has a climate very much like that of the Great Plains. +Turkestan and middle Asiatic Russia have a climate more like that of +the Great Basin. In a great number of localities in both European +and Asiatic Russia dry-farming has been practiced for a number of +years. The methods employed have not been of the most refined kind, +due, possibly, to the condition of the people constituting the +farming class. The government is now becoming interested in the +matter and there is no doubt that dry-farming will also be practiced +on a very large scale in Russia. + +Turkey + +Turkey has also a large area of arid land and, due to American +assistance, experiments in dry-farming are being carried on in +various parts of the country. It is interesting to learn that the +experiments there, up to date, have been eminently successful and +that the prospects now are that modern dry-farming will soon be +conducted on a large scale in the Ottoman Empire. + +Palestine + +The whole of Palestine is essentially arid and semi-arid and +dry-farming there has been practiced for centuries. With the +application of modern methods it should be more successful than ever +before. Dr. Aaronsohn states that the original wild wheat from which +the present varieties of wheat have descended has been discovered to +be a native of Palestine. + +China + +China is also interested in dry-farming. The climate of the drier +portions of China is much like that of the Dakotas. Dry-farming +there is of high antiquity, though, of course, the methods are not +those that have been developed in recent years. Under the influence +of the more modern methods dry-farming should spread extensively +throughout China and become a great source of profit to the empire. +The results of dry-farming in China are among the best. + +These countries have been mentioned simply because they have been +represented at the recent Dry-farming Congresses. Nearly all of the +great countries of the world having extensive semiarid areas are +directly interested in dry-farming. The map on pages 30 and 31 shows +that more than 55 per cent of the world's surface receives an annual +rainfall of less than twenty inches. Dry-farming is a world problem +and as such is being received by the nations. + +*** END OF THE PROJECT GUTENBERG EBOOK 4924 ***
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