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<br />,--I <br />.. to') <br />..'-J <br />.-4 <br /> <br />Daily evapotranspiration rates provided by the monitoring section of the Soil <br />Conservation Service were used to determine soil moisture deficits between most <br />irrigations. The initial soil moisture deficit prior to irrigation was determined by the <br />hand feel method which was substantiated by a gravimetric evaluation of selected <br />samples. <br /> <br />'.':) <br /> <br />A comparison of fields identified as M11, M 15. M43, M51, and M55 shows a <br />difference in water use between the same crops in different years and a difference <br />in crop use on the same farm (M43). <br /> <br />Field comparisons. <br /> ACRE INCH ACRE INCH ACRE INCH <br />FIELD APPLIED/a. RUN-OFF/a. DEEP PERC./a. <br />NUMBER CONV. SURGE CONV. SURGE CONV. SURGE <br />Mll-90 34.6 29.1 4.4 8.8 10.9 2.0 <br />Mll-91 51. 8 44.3 3.7 11. 4 15.9 5.0 <br />M15-90 76.9 49.3 32.5 16.9 20.7 10.7 <br />M15-91 69.5 50.2 24.1 14.8 23.1 14.5 <br />M15-92 57.4 45.6 20.7 6.0 26.5 19.5 <br />M43-90 65.8 50.8 16.2 17.5 31.2 13.7 <br />M43-91 85.2 71.8 36.0 24.7 23.7 22.3 <br />M43-92 61.5 67.0 18.0 14.2 14.2 26.6 <br />M51-91 32.5 22.2 16.3 9.8 4.1 2.1 <br />M51-92 38.1 21.9 15.4 8.0 5.7 0 <br />M51-93 24.5 19.1 8.2 7.4 1.1 0 <br />M55-93 55.5 42.2 12,2 8 -, 9.0 1.0 <br />. , <br /> DATA ANALYSIS: <br /> <br />Note the increased water use on farm M 11 between 1990 and 1991. This is a <br />well.managed orchard but water management can be improved by adjusting the <br />timing of the cut-back cycles to reduce runoff. Also, reduced set times combined <br />with proper cutback cycle timing should reduce deep percolation. This field was <br />converted to surge irrigation for the 1992 season. <br /> <br />Farm M 15 reduced the total amount of water used during the 1991 season when <br />compared to 1990 but set times were about the same so deep percolation was <br />increased during 1991. Seventeen of the 19.5 inches of deep percolation occurred <br />during the initial irrigation of the corn during crop year 1993. <br /> <br />Increased water use on farm M43 reflect the change from corn to alfalfa, During <br />the year of alfalfa establishment -1991- a larger amount of water is used to assure <br />seed germination and seedling development. Examination of set time and furrow <br />flow data, not included here, indicate extended set times during the second and <br /> <br />4 <br />