Laserfiche WebLink
<br />, <br /> <br />UXIFOB)1 IRRIGATION HITH A CLOSED-cO/mUTT, GRAVITY DIS7RIBcl'IOC; SYST):;:.' <br />S ' L R " 2 <br />tepl1en . aWJ.lns <br /> <br />Abstract <br /> <br />j,:'\.lscing closed-conduit irrigation systems Gre c.:1paDlc of savin:=; <br />\,.7dtcr by increasing application uniformity. But, hC'.c<lU,(:;c mos~ 0,[ :.:hl';-,~ <br />'{'\':.CjuirC' pumping to pressurize water for distributi.on, tht:' w-ate:c is <br />Sil.vcJ often at the expense of increased energy consumption. This :-:';":)2Y <br />("'~sc .c:Lhes a ne~v irrigation sys tem that redl-.\..~es t.ile energy req ulrc-':mC"n t <br />IJY using inexpensive, thin-walled, corrugated plastic pipe of suf- <br />ficient diameter that the pressure head oiten available irom a surface <br />~lLcll is sufficient. A simple instal=-.:lt~or. tec:lniquc) givinG 12x-crecL:-ly <br />nl;:;h application uniformity, is described ror c.r,e system ror i)(>lliwnl'~;-C <br />crot)s. Costs ror the system can be less than for comparable sprinkler <br />or- drip irrigation systems. <br /> <br />Wdter-distribution systems that use closed COlldllits are ?oteil- <br />t i.ally capable or higher i rrigatlon unifo:cn"il ty than surface sys tems. <br />^ closed-conduit water distrihution system m~kes it possibl_c LO aIII)ly <br />".;,::lCcr dt a rate low enough that it does not pond on the .soil surface. <br />T:,is l:ransrers control or infiltration from the solI to the system. <br />~::: Guring each irrigation, 'tvater is delivered uniformly in increments <br />sufficiently small that soil storage capaci ty is not exceeded, var j ~:- <br />tions in soil properties from place-to-place in a field no longer cause <br />G:Lfferc~ces in the quantity of 'tqater stored for crop use. Each plan-:: <br />can effectively receive i.ts \>later supply directly. For sparsely p:LonteJ <br />ceo i) !::> , like orchards or vineyards, uniform irrigation can be <::.chicvccl <br />'dit:l a system that fills small basins \.nth 2qu<Jl quantities 01: \vater. <br />flh~s pape!" describes such a system that operates at low pressure by <br />llsing large diameter lateral pipes. Use of chin-walled corrugated <br />polyethylene helps keep the cost low. <br /> <br />T\,,7o test systems have been installed in citrus groves--onc in TacTIel, <br />I.rizona, the other in Riverside, California. Ijoth consist of corru8~:;,u::.Q <br />~)olyctl1ylene pipe laterals buried about 0.6 ill (2 it) deep midHay bctHeen <br />eV0.ry other row of trees, with 9.5-mni (3IB-in) inside diameter (ID) <br />polyetnylene delivery hose extending underground from the lateral hath <br />Hays to the trunk of each tree. Flow is regulated by tile elev;:i::ion 0.[ <br />outrlo....., from the delivery hose at each tree. Both installatioils ",."ere. <br />designed for a nominal flow rate of 60 1::11/ see (1 gpm) to each tree. <br /> <br />lContribution from the U. S. Salinity Lab., Agricultural Research <br />Service, USDA, P. O. Box 672, Riverside, CA 92502. <br /> <br />2Research Leader. <br /> <br />C:u2961 <br />