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<br />(') <br />00 <br />..r) <br />,~ <br /> <br />,";) than the ave...age fo... fall g...ain <Table 7), and site 32 had deep <br />pe...colation of about 42 inches, ove... 200% of the ave...age. About 20 <br />inches deep pe...colation occu......ed du...ing the fi...st i......igation. <br />Site 29 dec...eased deep pe...colation f...om 30.0 inches in 1989 to 11.9 <br />inches in 1990 and inc...eased appl ication efficiency f...om 21 to 25% in <br />1990 compa...ed to 1989. At site 29, app...oximately 84% of seasonal deep <br />pe...colation occu......ed by the end of the second i......igation <Table 7>. <br /> <br />With small g...ain, the gene...al t...end in the Valley is to "black ove..." <br />the field du...ing the fi...st i......igation in the fall. Consequently, on <br />the ave...age, about 60% of seasonal deep pe...colation losses occu... by <br />the end of the second i ......igation <Table 7>. "Bla,~k ove..." may not be <br />needed if cultu...al p...actices could be found to sp...ead the wate... <br />I ate...a II y fo... stand estab Ii shment. A one yea... stlJdy by ARS in the <br />ea...ly seventies indicated that the p...actice of "black ove..." could be <br />avoided with two diffe...ent cultu...al p...actices that they expe...imented <br />with (pe...sonal communication with Dan Champion, CSU Extension, G...and <br />Junction). The SCS in G...and Junction has set up a team to look into <br />the possibi I ity of implementing these p...actices as a viable option in <br />the futu...e. Demonst...ation fields using these p...actices on co...n g...ound <br />of inte...ested fa...me...s wi II be establ ished this sp,-ing. <br /> <br />The i......igation efficiency fo... fall g...ain was only about 29%, simi I a... <br />to beans and onions. Efficiency could be inc...eased by ...educing wate... <br />appl ication and deep pe...colation. This can be accompl ished by <br />...educing set time and adjusting flow ...ate. <br /> <br />O...cha...d: Fou... sites cove...ing about 17 ac...es of apple o...cha...d with <br />su...face i......igation we...e monito...ed in 1990. Twenty one i......igation <br />events we...e ...eco...ded. <br /> <br />The ave...age deep pe...colation fo... these sites was 3.4 inches (Table 7) <br />in 1990, down f...om 4.3 inches in 1989 and 12.3 in 1988 (Table 4). The <br />ave...age deep pe...co I at i on was s light I y I ess than ",he acceptab I e deep <br />pe...colation (Table 6) necessa...y to keep salts below the ...oot zone. The <br />o...cha...ds had the lowest deep pe...colation losses compa...ed to othe... <br />c...ops <Table 7). <br /> <br />Site 18 had no deep pe...colation in 1990 <Table 7) as well as in 1989. <br />Ii'i 1988, the deep pe...colation was only 0.1 inches.. This site is <br />p...esumed to be unde... subi......igation because of high wate... table. Field <br />soi I moistu...e checks du...ing the summe... indicated high moistu...e <br />content in cont...ast to the compute... gene...ated so i I mo i stu...e data. <br />Th i s p...oduce... app lied less wate... than othe... o...char"d p...oduce...s but it <br />was adequate to meet the c...op wate... ...equi...ements because of <br />subi......igation. <br /> <br />Sites 39 and 47 also had low deep pe...colation. At site 47, the <br />p...oduce... waited long enough between i......igations and p...ovided Just <br />enough wate... to not deep pe...colate. Site 11 had a dec...ease in deep <br />pe...colation f...om 18.0 inches in 1988 to 12.8 inches in 1989 and 10.3 <br />inches in 1990. <br /> <br />26 <br />