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<br />in application of water o\'er a
<br />field ""ill result in deep perco-
<br />lation of water past the oonom
<br />of the root zone in the areas of
<br />greatest application - if the areas
<br />of least application receive ade.
<br />quate amounts. As irrigators, of
<br />course, we\'c experienced this.
<br />But we may not be doing any-
<br />thing about it. I
<br />Here is how Langley and Robb
<br />sum it up: "The simple, basic
<br />principle which most often go\'-
<br />erns irrigation cfficiencr is that
<br />water applied in excess of the
<br />space a\'ailaLle for storing mois-
<br />ture in thc soil (depleted soil
<br />moisture in the root zone) will
<br />be lost to surface runoff and/or
<br />decp percolation."
<br />AS n'E DEL tIE [urtber into rbe
<br />I..mlglry'Robb resume, perbups
<br />we CdU begin to draw some prac.
<br />tical COIlclIlS;OI1S to tbe common.
<br />place question, "Should J con.
<br />tinue pumpiug during a r,1il1, or
<br />should I Slop pumping MId start
<br />again wbcll tbe mill is over?"
<br />Hemembcr this. Once we'vc
<br />decided to irrigate on a gi\'en
<br />date and have decided on the
<br />rotal volume of water to be
<br />applied, the minimum losses and
<br />the maximum attainable effi.
<br />cienc)' ha\'e been fixed. ~o
<br />amount of additional irrigation
<br />labor can decrease the losses or
<br />increase the efficiency.
<br />One factor (surface runoff)
<br />competes with another factor
<br />(deep percolation) to issue a call
<br />to the irrigator for exacting
<br />application. If we try to carefully
<br />control water on the field in
<br />order to reduce surface runoff,
<br />we will become tangled in :l::::
<br />web of increased deep perc~'
<br />lation. since the total wa:r:r
<br />10s5ts can't be reduced. So. :0
<br />achie\'e reasonable irrigation e::':-
<br />ciencies, we need to apply a
<br />method which will allow uni:o:::I
<br />application and retention i:l a
<br />field of an amount of wate~ :'".'..:
<br />substantiallr in excess of ::-.~
<br />expected soil moisture dep:e:::.::.
<br />Our absolute objeeti\-e s::':.~::
<br />be to apply just the amo:..::-.: ..
<br />water that is needed - ..,
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<br />INSTALL DOLE' FLOI'.
<br />ON ANY TYPE SPRIf~:~1.
<br />IRRIGATION SYSTEL'l
<br />
<br />en
<br />(""l
<br />
<br />co
<br />c..!
<br />
<br />r
<br />-
<br />
<br />-
<br />
<br />NEV IRRIGI1TIOi! mOTOR C
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<br />~ i~: 7J.....'l. ~'."'.Il
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<br />_.~- '-'
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<br />-OU"-NTH~ i~FG.CO.
<br />
<br />-
<br />
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<br />
<br />I'
<br />
<br />I
<br />I
<br />
<br />c All steel
<br />
<br />
<br />construction
<br />"Available in G'
<br />widths in any Ie,
<br />
<br />DEAL ERS WANTED
<br />
<br />QUINTlI.U.I:SAS '71S2 'NOt:I1SC.1310
<br />
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