DRY-FARMING: A SYSTEM OF AGRICULTURE FOR COUNTRIES UNDER A LOW RAINFALL TEXT

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