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<br />. <br /> <br />. <br /> <br />plan (Exhibit 1). We also provide the farmer with an "Irrigation <br />Guide" (Exhibit 2). This guide includes information on the inflow <br />time and rate for applying various depths to each border. <br /> <br />By comparing exhibits 3 and 4, we can see the potential of an <br />improved system with proper management. Exhibit 3 shows the irri- <br />gation application in 1975 before any onfarm improvements. Exhibit <br />4 shows the irrigation application after onfarm improvements. In <br />this instance, the before and after crops are the same. This shows <br />the significant increase in efficiency, which will occur on the very <br />high water use lands. <br /> <br />An analysis of contracts, on which all conservation practices <br />have been applied, shows that for the 1977 crop year an average re- <br />duction in deep percolation of 82 percent has occurred. The net <br />increase in onfarrn irrigation efficiency was 31 percent. For the <br />1978 crop year the net increase in efficiency was 28 percent, and the <br />reduction in deep percolation was 74 percent (Table 1). The crops <br />listed are those being grown after improvements and mayor may not <br />correspond to the crop grown prior to improvements. The reduction <br />in deep percolation for 1977 is estimated to be 7,434 acre-feet on <br />2,920 cropped acres. The reduction in deep percolation for 1978 was <br />15,110 acre-feet on 7,525 cropped acres. The farmers indicate that <br />the improvements have generally cut their irrigation time in half. <br /> <br />Irrigation water management plans developed for drip systems <br />describe the time required to supply various volumes of water per <br />tree per day. They also indicate the water amounts needed at <br />different times during the crop year. The Science and Education <br />Administration-Agricultural Research is conducting research to <br />determine the quantity of water needed per tree per day. At present, <br />systems are designed to deliver an amount equal to the currently <br />accepted consumptive use rate for the crop. As new information be- <br />comes available, SCS technical guides and recommendations will be <br />modified accordingly. <br /> <br />The total effect the onfarm improvement program will have on re- <br />ducing return flows has been very encouraging. The results for the <br />past two years indicate the program will accomplish and probably <br />exeeed the on farm efficiency level established in the "Special <br />Report," Measures for Reducing Return Flow from the We 11 ton-Mohawk <br />Irrigation and Drainage District, September 1974 by the Advisory <br />Committee on Irrigation Efficiency. <br /> <br />-7- <br />