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Show NATURE MUST EE IMITATED' No Matter How Water Is Applied, All ana Blazing Sun Will Take Up Much Moisture. It is the irrigator's business to tml: tate natural conditions as closely as possible. At the very beginning be is handicapped by the conditions .that make irrigation necessary. No matter mat-ter how he applies his water, the dry air and the blazing sun of the arid region re-gion will through rapid evaporation deprive him of a large part of the moisture. In other words, it requires more Irrigation water than rain water to moisten the same area of soil to the same depth and degree of satura-I satura-I tion. Even after he has succeeded in getting the water into the soil, the average irrigator does not know where it goes or what becomes of It. As long as irrigation water was plentiful and the irrigated area small, loss of moisture through wasteful methods failed to attract attention. With small regard to water economy, giving no thought to the damage Inflicted In-flicted upon both land and crop through excessive moisture, the farmers farm-ers after leveling their fields flooded ( them, allowing the water to seek its way without much guidance or attempt at-tempt at proper distribution. The check or basin method under which the area to be irrigated is divided by riages iulu reciaiisuifli size brought about better distribution, but it did not reduce evaporation losses and it interfered with the use of farm implements. Under this method meth-od enormous evaporation losses were caused by the moistening of the entire en-tire surface and early cultivation was made impossible. Of late years the most progressive irrigators have adopted the furrow method wherever possible, especially in orchards and , vineyards. Heat and wind movement increase evaporation. A reduction of the temperature tem-perature by seven degrees will, according ac-cording to investigations, decrease the rate of evaporation from water surfaces sur-faces one-tenth of an inch a day. Heat and wind movement as causes of evaporation are strongest at the surface sur-face of the soil. Observations in the arid region have frequently shown '. temperatures of 135 degrees at the surface of unshaded soil, with a decrease de-crease of from twenty to thirty degrees de-grees five inches below the surface. Furrow irrigation, therefore, by lessening less-ening the area moistened, by protecting protect-ing the water from wind and from the high surface temperatures, makes e larger percentage of it available for the use of the plants. |
