17在干旱地区最大化水分生产率的一种非充分灌溉农业战略策略

ReviewDeficitirrigationasanon-farmstrategytomaximizecropwaterproductivityindryareasSamGeerts*,DirkRaesK.U.Leuven(UniversityofLeuven),DivisionofSoilandWaterManagement,Celestijnenlaan200E,B-3001Leuven,BelgiumContents1.Rationale......................................................................................................12752.Cropwaterproductivity..........................................................................................12762.1.Theconcept..............................................................................................12762.2.Thecropwaterproductionfunction...........................................................................12763.Deficitirrigation:deliberatelytoleratingdroughtstress.................................................................12773.1.Theconceptofdeficitirrigation..............................................................................12773.2.Researchresultsfordifferentcrops............................................................................12773.2.1.Seasonalcropwaterproductionfunctions...............................................................12773.2.2.Droughtstressdifferentiatedbyphenologicalstage.......................................................12783.3.Advantagesandconstraintsofdeficitirrigation..................................................................12783.4.Reasonsforincreasedwaterproductivityunderdeficitirrigation....................................................12794.Modelingasatoolforassessinganddevelopingdeficitirrigationstrategies.................................................12795.Conclusion.....................................................................................................1280Acknowledgements..............................................................................................1280References.....................................................................................................12821.RationaleTosustaintherapidlygrowingworldpopulation,agriculturalproductionwillneedtoincrease(Howell,2001),yettheportionoffreshwatercurrentlyavailableforagriculture(72%)isdecreasing(CaiandRosegrant,2003).Hence,sustainablemethodstoincreasecropwaterproductivityaregainingimportanceinaridandsemi-aridregions(DebaekeandAboudrare,2004).Traditionally,agriculturalresearchhasfocusedprimarilyonmaximizingtotalproduction.Inrecentyears,focushasshiftedtothelimitingfactorsinproductionsystems,notablytheavailabilityofeitherlandorwater.Withinthiscontext,deficitirrigation(DI)hasbeenwidelyinvestigatedasavaluablestrategyfordryregions(English,1990;Pereiraetal.,2002;FereresandSoriano,2007)wherewateristhelimitingfactorincropcultivation.WereviewrecentresearchonthemaximizationofproductivityperunitofwaterbyDIandwediscusscropwaterproductivitymodelingasatoolforassessinganddesigningDIstrategies.AgriculturalWaterManagement96(2009)1275–1284ARTICLEINFOArticlehistory:Received9May2008Accepted14April2009Availableonline14May2009Keywords:WateruseefficiencyCropevapotranspirationWaterstressAridregionsWaterproductionfunctionABSTRACTDeficitirrigation(DI)hasbeenwidelyinvestigatedasavaluableandsustainableproductionstrategyindryregions.Bylimitingwaterapplicationstodrought-sensitivegrowthstages,thispracticeaimstomaximizewaterproductivityandtostabilize–ratherthanmaximize–yields.Wereviewselectedresearchfromaroundtheworldandwesummarizetheadvantagesanddisadvantagesofdeficitirrigation.ResearchresultsconfirmthatDIissuccessfulinincreasingwaterproductivityforvariouscropswithoutcausingsevereyieldreductions.Nevertheless,acertainminimumamountofseasonalmoisturemustbeguaranteed.DIrequirespreciseknowledgeofcropresponsetodroughtstress,asdroughttolerancevariesconsiderablybygenotypeandphenologicalstage.IndevelopingandoptimizingDIstrategies,fieldresearchshouldthereforebecombinedwithcropwaterproductivitymodeling.2009ElsevierB.V.Allrightsreserved.*Correspondingauthor.Tel.:[phone];fax:[phone].E-mailaddresses:[e-mail],[e-mail](S.Geerts).ContentslistsavailableatScienceDirectAgriculturalWaterManagementjournalhomepage:–seefrontmatter2009ElsevierB.V.Allrightsreserved.doi:10.1016/j.agwat.2009.04.0092.Cropwaterproductivity2.1.TheconceptCropwaterproductivity(WP)orwateruseefficiency(WUE),asreviewedbyMolden(2003),isakeytermintheevaluationofDIstrategies.Waterproductivitywithdimensionsofkgm3isdefinedastheratioofthemassofmarketableyield(Ya)tothevolumeofwaterconsumedbythecrop(ETa):WP¼YaETa(1)ETareferstowaterlosteitherbysoilevaporationorbycroptranspirationduringthecropcycle.Sincethereisnoeasywayofdistinguishingbetweenthesetwoprocessesinfieldexperiments,theyaregenerallycombinedunderthetermofevapotranspiration(ET)(Allenetal.,1998).Inwater-scarceregions,cropswithhighWPshouldbepreferred,althoughthisisnottheonlyfactor.Indeed,whilehigh-energyfruitandgraincrops(e.g.cropswithhighproteincontent)mayhavealowerabsoluteWPvalue(StedutoandAlbrizio,2005),theirnutritionalvalueishigher,whichshouldbeconsideredwhenassessingthesecro