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<br />~. <br />OJ <br />c') <br />o <br /> <br />--, <br /> <br />.:.:; <br /> <br />individual irrigations). The sites with poor irrigation <br />efficiencies generally were irrigated sooner and longer than <br />needed. Improper scheduling and long set times caused excessive <br />deep percolation on some of the sites. Irrigation efficiencies can <br />be improved at some sites with better irrigation scheduling and <br />adjusting set times or inflow rates. <br /> <br />d. Surge and conventional Irrigation Comparison: <br /> <br />In five fields, surge and conventional sites were located side by <br />side (separate acreages) for comparison. On these fields, 29 surge <br />irrigation events were monitored on about 47.3 acres; 29 <br />conventional irrigation events on 53.4 acres were also monitored. <br />Comparison of surge and conventional irrigation in the same field <br />with similar soils indicated that with the use of surge systems <br />there could be reductions in water application; resulting in <br />tailwater and deep percolation reductions. <br /> <br />At all four comparison sites, the reduction in water application <br />per acre was directly related to the number of hours of water <br />applied per acre. With surge, the reduction in hours per acre of <br />water applied compared to conventional irrigation varied from 2 to <br />20 hours. This related to an average savings of 17% or 9 hours per <br />acre of water application with the use of surge systems (Table 5). <br />This means a reduction of about 15% in water application to the <br />field. Water application savings ranged from 3.0 to 19.3 acre <br />inches per acre with an average savings of 9.2 acre inches per acre <br />(Table 5). However, site 50 with a surge system had more water <br />applied to the field than the conventional site (Table 5). <br /> <br />Comparison between surge and conventional irrigation also showed a <br />reduction in tailwater amount with surge. Two surge sites (39, 50) <br />had higher runoff than conventional ones, however, on the average <br />there was a 3.8 acre inches per acre reduction (Table 5) for the <br />season, about 21% savings. <br /> <br />with reduced water application at surge sites, infiltrated depth <br />also decreased by an average of 5.4 inches per acre, about 12% <br />savings (Table 5). Reduction in infiltrated depth varied from 0.1 <br />acre inches per acre to 11.3 acre inches. The reduction in <br />infiltrated depth also helped reduce deep percolation. Table 5 <br />shows that deep percolation reduction is directly proportional to <br />infiltrated depth. <br /> <br />Reduction in infiltrated depth and deep percolation helped increase <br />application efficiency at surge sites by an average of 4.7% in 1991 <br />and about 12% in 1990. The difference in application efficiency <br />between surge and conventional sites varied from a low of -0.6% to <br />a high of 9.5% for the season (Table 5). <br /> <br />20 <br />