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Show ECONOMICAL DISTRIBUTION OF IRROT10N WATER By L. M. WINSOR, Utah Agricultural College. Oregon Short Line Railroad Demonstration Demon-stration Train Lecture. According to many historians, irrigation irri-gation is one of the oldest applied arts; one writer even claims that it is made a distinctive feature of the middle status of barbarism. Ancient Egypt became the granary of the world as a result of natural irrigation through the overflowing of the Nile; through irrigation Chaldea, Assyria, and Babylonia, located as they were in a practically rainless country along the valley of the Tigris and Euphrates, Euph-rates, rose to enviable prominence and dominion. The Chinese, the Romans and the Moors, all made use of Irrigation. Irriga-tion. In this country we find evidence of it as practiced by the ancient inhabitants inhab-itants of this continent and later in the gardens of the old mission fathers of southern California. Numerous other examples to prove the importance import-ance of irrigation as a factor In nation-building might be cited; but to the Anglo-Saxon race the art had its birth but little more than half a century cen-tury ago. This seems doubly strange when we look into history and find that at this time over 138,000,000 acres of land had been reclaimed by irrigation irriga-tion in different parts of the world. Perhaps this can be explained on the theory that the Germanic peoples have always written history much faster than they have read it. However this may be, the first attempt at-tempt by the Anglo-Saxons to reclaim re-claim the arid wastes of land was made in the summer of 1847, in the Salt Lake valley by a little band of Mormon pioneers. To them we owe the birth of the modern art of irrigation, irriga-tion, and the working out of the co operative system as we have it in practice today. The irrigation contagion soon spread and became not only the governing gov-erning factor in the establishing of Mormon towns, but in the colonizing of the entire arid west. Irrigation as an art falls into two divisions: 1st. Irrigation as a primary art, and 2nd. Irrigation as a secondary art. By the first we mean the using of irrigation to take the place of cultivation, cultiva-tion, fertilization, and so on; and by the second we mean the using of irrigation ir-rigation water merely to supplement the natural precipitation. The latter is the correct use of irrigation. If a farmer uses dry farm methods along with his practice of irrigation he cannot can-not go far wrong. One of the grave mistakes made by our early irrigators was the Indiscriminate Indis-criminate use of water, with the re-, suit that thousands of acres of. once productive iand have been "rendered into veritable swamps, and alkali beds. The lamentable feature of this question is -the fact that with our sixty odd years of experience some of our farmers are still following these erroneous methods, and are ruining not only their own farms but those of their unfortunate neighbors, by a too liberal and careless application of water. This is especially true in some of the new-er sections where a more or less heavy application is needed for the first few years. The trouble is that they do not "set the brakes" until it is too late. Once a new soil some of you In your work; for, after all, each of your Individual problems must be solved by yourselves. The amount of plant growth is do-pendent do-pendent in a decided measure upon the amount of moisture, within certain cer-tain limits, in the soil. The supplying and maintaining of this moisture in an amount which will bring the greatest great-est return is, then, our problem. The water found in soils is of three kinds: 1st. Free water . or the water found between the soil particles of a saturated soil. 2nd. Capillary water or that which is held in a thin film around each of the soil particles of a moist but not saturated soil. This is the water used by the plant in its growth. 3rd. Hygroscopic water which is the water held by the soil but which, in all probability, is not used by the plant. Only aqueous or water plants can grow in a soil containing free water. Hence our problem is confined to the regulation of the capillary water only, and to the conditions which govern plant growth. There are three ways by which soil moisture can escape: 1st. By sinking into deep soils out of reach of the plant roots, and escaping escap-ing by under drainage. 2nd. By evaporating from the surface. sur-face. 3rd. By passing through the plant itself in a process known as transpiration. trans-piration. Each of these losses can be governed gov-erned to a certain extent. The first by making lighter applications of water at each irrigation. The second, or surface evaporation, can be checked check-ed by cultivating the surface sufficient suffi-cient to form a dust mulch, thus closing clos-ing up the opening of the capillary tubes which form when the surface soil begins to dry out. And the third or transpiration can be checked by the addition of soil fertility or by ordinary or-dinary cultivation. Thus, the last two can be governed by the simple operation opera-tion of stirring the surface after an irrigation. The thought is prevalent among farmers that a certain amount of water must be used by a plant in order or-der to produce a certain weight of dry matter. As early as 1699 Woodward found that it required less water to produce a pound of dry matter in a plant growing in a rich soil where the plant food was evenly balanced, than in one of opposite nature. Later, in 187S, a German investigator found that the yield of dry matter was greatest where transpiration was least. He also found that the enriching enrich-ing of the soil enabled the plant to produce dry matter with less water. Now the question may arise in your minds: Why should cultivation decrease de-crease the amount of water actually used by the plant? Cultivation permits per-mits the air and sunshine to enter the soil more readily, causing a consequent conse-quent liberation of plant food, which is equivalent in effect to the addition of the food artificially. Y That cultivation actually decreases the amount of water used by the plant is stiown in the results .of experiments ex-periments conducted at the Utah experiment ex-periment station in the vegetation house. Certain tanks were planted to corn. An equal number of tanks containing con-taining the same kinds of soil were left bare for a check on the evaporation evapora-tion from the surface. Forty-eight hours after each irrigation and then every week, half the surfaces were cultivated while the other half were left bare. Table No. 1 shows the results. re-sults. TABLE NO. 1. ' ' I '--J Cultivation vs. Transpiration. Average Aver-age for Three Years. has been moistened below the range of the plant roots it needs a great deal less water than it required to begin with, the actual amount for the maturing ma-turing of any certain crop will vary only with the seasons, cultivation, and so on being the same. This being the case it is possible to make an economical econ-omical distribution of the water at one's disposal and use it in a way which will not be detrimental to the soil and in a way to result in the greatest returns to those concerned. This question is one of prime importance import-ance to the farmers in this arid region and too much stress cannot be laid upon it. Situated as we are in a section where the rain and snow-fall is very low, we are dependent almost absolutely abso-lutely upon irrigation water to increase in-crease our agricultural possibilities. The farming lands are almost unlimited unlim-ited within the borders of our states, but there is a decided limit to the water supply. The question then, is not how much land have we? but how much water have we at our disposal? dis-posal? . The State of Utah represents an area of over 82,000 square miles, of which only 1,700 square miles are cultivated cul-tivated and less than 1.000 square miles or slightly under 1.25 per cent of the total are actually irrigated, fldaho is in a similar condition.) What we need then most of all Is a distribution of the water in such a way that the greatest possible returns re-turns can be obtained. The problem is not difficult of solution if we only apply ourselves to a study of conditions condi-tions as we find them and to the information in-formation available. In the short time at my disposal I hope to open up a line of thought which will help PoumlH water Kinds of Cultivation. used by plant Soil. . I" produ.-e l lb. dry matter 74 hours after College Irrigation 252 Loam Then Weekly None 603 48 hours after Sample Irrigation 428 Clay Then Weekly None 535 18 hours after ' Irrigation 582 Clay Thcn Weekly None 755 As the soil in each set of tanks was alike, and as all other conditions except ex-cept the 'Cultivation were identical it necessarily follows that the reduced amount of water required to produce a pound of dry matter in the cultivated cultivat-ed pot was due to the cultivation aud, its effects. There is, then, a double reason for cultivating your crops. You not only hold the moisture in the soH by preventing pre-venting evaporation from its surface, but you make it possible for the moisture mois-ture retained to produce in some Instances In-stances more than twice as much plant growth. This means that by the practice of cultivation you can make your irrigation water cover Just twice as much ground. There is a marked variation In the amounts of water required for different dif-ferent varieties of plants. For example, exam-ple, all other conditions being equal, the potato plant requires more than two and one half times the water to to produce a pound of dry matter that the corn plant requires. (To be Continued.) |