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Show MUCH LOSS OF PLANT FOOD Leaching of the Soil by Irrigated Water Bhould Be Avoided a Much ae Possible. (P-y C. W. mt.VKIt. rtsh t'nlvrratty Ex-p.-rlmrnt Btallon i A certain amount of plant food Is removed from tlio land by irrigation water which should bo restored to all cultivated soils. If aa much is returned to a productive soli as Is taken away, such a soli will never become exhausted. Therefore an especial couslderatlon should be given to all phases of the subject that deals with the conservation of the plant food elements ele-ments that are already in the soli. In Idaho's irrigated districts the largest part of the plant food taken from the soil Is removed by the growing grow-ing crojMi, but the amount of valuable valua-ble plant forming elements that are lost in waste and drainage water may not be Inappreciable. The results of some experiments, conducted at one of our leading experiment ex-periment stations, located in a non-Irrigated non-Irrigated district, show that the drainage drain-age water carries away an average of 37. 6 pounds of nitrogen per acre a year from the top twenty inches of Boll. Although potash, phosphoric acid and lime are not dissolved from the soils as readily as nitrogen, it has been clearly shown that the amount of those elements in the drainage waters wa-ters Is not small. If the mineral plant foods are so easily detected in the drainage from lands watered only by rain, the loss on an Irrigated farm, unless the water wa-ter is carefully applied, will be considerably con-siderably greater. If a large stream of water la allowed to run all night through short rows of vegetables and berries and for days over grain and alfalfa fields these elements that are assimilated by the growing plants will either be carried below the range of plant roots and lost in the underground under-ground drainage, or will be carried off In the waste ditch to enrich some farm further down the canal. To reduce tbls leaching of the soil by the Irrigated water to a minimum, as far as possible excessive flooding, resulting in large streams of waste water, should be avoided. |