简介：Theobjectivesofthepresentstudyweretoexaminethespatialpatternsofswarddrymatter(DM)andnitrogen(N)yieldsinagrasssilagefieldatfirst,second,andthirdcutsovera3-yearperiod;quantifytheirtemporalstabilitieswithtemporalstabilitymaps;andassessthepotentialforsite-specificmanagementineachpasture-growingperiodusingclassifiedmanagementmaps.Atcut1,thespatialpatternsofDMandNyieldsprovedtobewelldefinedandtemporallystableandwerelikelytobeduetodifferencesinthenetNmineralizationratesacrossthefieldduringspring.Incontrast,atcut2,thepatternsofDMproductionwerepatchyandtemporallyunstable.Itwasconcludedthat,inprinciple,asimplesite-specificapproachtoNfertilizationwouldbepossibleinthisfieldduringspringatcut1.Atlaterharvests,therationaleforasite-specificapproachtofertilizermanagementwaslessclearwithlogisticsappearingtobemorecomplexandlessfeasible.

简介：Investigationswereconductedtoquantifylitterfall,andlitterandnutrientaccumulationinforestfloor,andtoacquireinformationonlitterdecompositionandnitrogenandphosphorusreleasepatternsinthreedifferentsubalpineconiferousforests,aplantation(Pl),asecondaryforest(SF),andaprimitiveforest(PF),inwesternSichuan,China.Thelittertrapmethodwasusedtoevaluatelitterfallwiththelitterbagmethodbeingutilizedforlitterdecomposition.Seasonalpatternsoflitterfallweresimilarinthethreeforests,withtwopeaksoccurringinSeptember-NovemberandMarch-May.Theplantationrevealedanannuallitterfallof4.38×103kgha-1,whichwassimilartothoseofSFandPF,butPlhadalowermasslossrateandahigherC/Nratio.TheC/Nratiomaybeasoundpredictorforthedecompositiondifferences.Nconcentrationsofleaflitterinboththesecondaryforestandprimitiveforestincreasedfirstandthendecreased,andthepercentagesoftheirfinal/initialvalueswere108.9%and99.9%,respectively.Pconcentrationinthethreeforestsincreasedbytheendofthestudy.TheresultsoflitterfallanddecompositionindicatedthatintheplantationthepotentialtoprovidenutrientsforsoilorganicmatterwassimilartothoseofSFandPF;however,itsslowerdecompositionratecouldresultinasomewhattransientaccumulationoflitterintheforestfloor.

简介：Threepatternsofpotashapplicationwereusedinthecorn-wheatandrice-wheatrotationexperiments,whichwereconductedintheuplandandwetlandofSiyangCounty,northernJiangsuProvuince,andthewetlandofLiyangCity,southernJiangsuProvince.Theresultsof5croppingseasons(2seasons/year)showedthatthedirectresponseofcorntoKwaslargerthanthatofwheat,butnodifferencewasfoundbetweenriceandwheatinSiyangwhenthetotalannualamountofKwasappliedonlyinonecroppingseason.However,theresponseofwheatwasmuchgreaterthanthatofriceinLiyang.Ifpotashwasappliedintheprecedingseason,theresidualeffectofKonwheatwaslargerthanthatonricebothinSiyangandLiyang,butlessthanthatoncorn,Thetotaleffect(directandresidualeffects)ofKappliedtocornorricewasgreaterthanthattowheatinSiyang,butthattowheatwasgreaterinLiyang.ThedirectandtotaleffectsofKapplicationintheuplandwerelargerthanthoseinthewetlandofsiyang;butfrothewetland,theeffectswerelargerinLiyangthaninSiyang,especiallyinthewheatseason.Theresultsdemonstratedthatthemostprofitablepracticetoberecommendedtothelocalfarmerswastoapplyalimitedamountofpotashtoonlyriceorcornbutnottowheat.EquallyapplyinghalfofthetotalannualamoutofKtoeachofthecropsmaybeadvisableinordertolessenpossiblefertilizationrisks.