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<br />of 1ncO/Tle fer many hndholcers, so the average irrigated hnd hokfng fs enly <br />26 acres. <br /> <br /><:) <br />Q <br />U' <br />... <br /> <br />Oeterm1n1nc Irri~at1on Parall'eters. The model assumed the five crops coula <br /> <br />be grown wfth any of ten COmbinatfons of 'Water applicatfon technologies and <br /> <br />management techn f ques. <br /> <br />Sfx irrigation technologies are cons1derec: <br /> <br />earthen <br /> <br />ditch 'Idth siphon tubes. concrete l1nec d1tch 'lir1th siphon tubes, sated pipe, <br />ported d1tch, sem1-automated ported ditch, and cablegat1on.5 <br /> <br />Four 'Water application optlons are 1ncluded. <br /> <br />The first is the <br /> <br />convent1onal irrigat10n techn1que for the Grand Valley of 24 hour 1rr1gation <br /> <br />sets for ro.... crops and 48 hour sets for hay and grass. This approdch nermally <br /> <br />results in very high tal1water losses and excessive deep percolation, <br /> <br />especfally in the first t'Wo 1rrfgatfons of the year when sol1 permeacilfty is <br /> <br />h1gher. One technique to raise efficiency is to shorten the 1rrfgat1on timing <br /> <br />to 12 or 18 hour sets. This can be combfned w1th the 1nitial use of two siphon <br /> <br />tubes per furro'W. cutting back to one tube after the entire length of the <br /> <br />furrow has been 'liretted. Th1s technique, called manual cutback, saves water and <br /> <br />increases eff1ciency; it is more easily done by adjusting the rate of flo'W frcm <br /> <br />gated pfpes or ported d1tches. F1nally, semf-automated systems (such as ported <br /> <br />ditch wfth timer-operated drop gates) and cablegat10n can shorten 1rrigat1on <br /> <br />t1me and change sets as well. Thus. the ten 1rr1gation optfons are 1) earthen <br /> <br />ditch, 2) earthen ditch with short sets. 3) lined ditch, 4) lined ditch with <br /> <br />short sets,S) sated pipe, 6) gated pipe 'W1th manual cutback.. 7) ported ditch.. <br /> <br /> <br />8) ported ditch with manual cutback, 9) semi-automated ported ditl:r., anc 10) <br /> <br />cablegat1on. <br />.....n a<:'d1t1onal management response to salinity control incentives is <br />partial land retirement. This alternative ....as lin:.1tec to 8,000 of tl'le 50,000 <br /> <br />7 <br />