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<br />tn <br />~. <br />C'i <br />C.J <br />:-~) <br /> <br />. <br /> <br />. <br /> <br />,~. ., <br /> <br />is p~esumed to be unde~ subi~~igation because of the ove~wate~ing of a <br />fie I d to the east by anothe~ fa~me~. Th i s p~oduce~ app lies I ess wate~ <br />than the othe~ o~cha~d p~oduce~s but app lies enough wate~ to meet the <br />c~op needs. He p~obes his field now and then, and says the~e is <br />plenty of moistu~e below 3 feet, th~oughout the summe~. Because of <br />f~eeze damage, site 14 had 1 less i~~igation in 1989 and the peach <br />t~ees we~e i~~igated fo~ plant maintenance only. App~oximately 20 <br />inches I ess wate~ was app lied in 1989 compa~ed to 1988. <br /> <br />Site 11 had a dec~ease in pe~colation f~om 18.0 inches in 1988 to 12.8 <br />inches in 1989, a dec~ease of about 29%. This could be due to change <br />in fa~m owne~ship. The new owne~ and ope~ato~ t~ied to follow p~ope~ <br />i~~igation wate~ management p~actices by ~efe~~ing to the monito~ing <br />data p~ovided to him. <br /> <br />The ave~age deep pe~colation and pe~centage dist~ibution by i~~igation <br />events fo~ the 3 o~cha~d sites a~e p~ovided in Table 8. <br /> <br />In 1989, the seasonal application efficiency inc~eased at site 11 and <br />14 but dec~eased s light I y at site 18 compa~ed to 1988 <Tab I e 2) <br />I~~igation monito~ing data and soi I moistu~e deficit data we~e <br />p~ovided to al I 3 o~cha~d p~oduce~s towa~ds the middle of the <br />i ~~ i gat i on season. Two of the p~oduce~s occas i ona II y ~efe~~ed to the <br />info~mation p~ovided to help them with thei~ wate~ management <br />decisions. <br /> <br />G~apes: Two sites cove~ing about 10 ac~es we~e monito~ed in 1989, the <br />same as 1988. The G~and Va I I ey has about 80 ac~es of g~apes <Tab I e 7) <br />and the monito~ed sites ~ep~esent mo~e than 10% of the total vineya~d <br />ac~eage. <br /> <br />Tab I e 2 shows that on I y 5 ac~es was mon i to~ed in 1989; in the past <br />fu II ac~eage <10 ac~es) was i nc I uded in the Annua I Summa~y Tab I e. <br />This 5 ac~es ~ep~esents wetted ac~eage and not the total field <br />ac~eage. Due to plant spacing and mlc~osp~ay patte~n, only about 50% <br />of the total field ac~eage gets wetted du~ing i~~igation. In 1989, <br />i~~igation volume and deep pe~colation calculations have been done on <br />the basis of wetted ac~eage. <br /> <br />Both sites a~e i~~igated by mic~osp~ay i~~igation systems which <br />gene~ally has about 75 to 80% appl ication efficiency. In 1989, the <br />maximum potential efficiency was assumed to be 90% with 10% <br />evapo~ative losses. In the past, potential efficiency was estimated <br />to be 80% with 20% evapo~ative losses. <br /> <br />Site 17 has been monito~ed since 1985. Deep pe~colation at this site <br />was ~educed f~om 10.7 inches in 1985 and 1986 to 2.3 inches In <br />1987 <Table 5). In 1988, the deep pe~colation losses inc~eased to 4.3 <br />inches and then dec~eased to 2.3 inches in 1989. The deep pe~colation <br />losses in 1989 was 28% less than the acceptable deep pe~colation <br />~equi~ed fo~ salt leaching (Table 4). As discussed ea~lie~ in this <br />~eport, the f~igid tempe~atu~es in Feb~ua~y damaged most of the <br /> <br />21 <br />