简介：A5－yearexperimentonwaterbalancehasbeenconductedinaflatrainfedwheatfieldwithanareaof66×100m^2inFengqiu,HenanProvinceinChina.Basedontheanalysisofsemi-variancefunctionsconductedwithsoilmoisturesamplestakenfrom77nodesofa10×10m^2grid,thesoilmoisturedistributioninthefieldwasstructuralwithatemporalstability.Accordingtotheautocorrelationrangeofthesemi-variancefunction,6siteswereselectedforthedeterminationofsoilwaterconditions.Thecharacteristicofprobabilitydensityfunctionofthedifferencesofwaterstorageintwosetsofmeasurementsshowedthatthedistributionofthesevariablesinthefieldwasanormalone.Theerrorintheestimationoftheaverageof5randomsampleswas14%(α=0.10),andtheerrorsofwaterconsumptionbywheatduringtheexperimentswereestimatedtobe6-13%.Simetheexperimentalfieldwaslargeenoughtoavoidanyedgeeffect,theresultsobtainedshouldtallywiththeactualsituation.Yetthesoilsystemwasheterogeneous,sowemustfollowtheprinciplesofstatisticsandgeostatisticswhendescribingthesystem'sstatuswiththeaverageofthesamples.

简介：AfieldexperimentwasconductedatKezuohouqiCounty,InnerMongoliaAutonomousRegionofChina,whichwaslocatedonthesoutheasternedgeoftheHorqinSandyLand,tostudythespatialvariabilityofsoilnutrientsforasmallscale,nutrient-poor,sandysiteinasemi-aridregionofnorthernChina;toinvestigatewhetherornottherewere'islandsoffertility'attheexperimentalsite;andtodeterminethekeynutrientelementsthatsustainedecosystemstability.Resultsobtainedfromgeostatisticalanalysisindicatedthatthespatialdistributionpatternofsoiltotalnitrogen(STN)wasfardifferentfromthoseofsoilorganicmatter(SOM),totalphosphorus(STP),andtotalpotassium(STK).ComparedtoSOM,STP,andSTK,STNhadalowerstructuralheterogeneityratioandalongerrange,whileotherelementswereallsimilar.Inaddition,STNhadanisotropicspatialstructure,whereastheothershadananisotropicspatialstructure.Thespatialstructurepatternsofherbagespecies,cover,andheightalsodiffered,indicatingthatspatialvariabilitywassubjectedtodifferentecologicalfactors.Differencesinthespatialvariabilitypatternsamongsoilnutrientsandvegetationpropertiesshowedthatsoilnutrientsforasmall-scalewerenottheprimarylimitingfactorsthatinfluencedherbagespatialdistributionpatterns.Incorporatingspatialdistributionpatternsoftreespecies,namely,Pinussylvestrisvar.mongolicaLitv.andshrubLespedezabicolorTurcz.inaresearchplotandusingfractaldimension,SOM,STP,andSTKwereshowntocontributetothe'islandsoffertility'phenomenon,howeverSTNwasnot,possiblymeaningthatnitrogenwasakeylimitingelement.Therefore,duringrestorationofsimilarecosystemsmoreattentionshouldbegiventosoilnitrogen.