简介：Basedonthestrongchelatingpropertyofbathophenanthrolinedisulfonicacid(BPDS)withFe(Ⅱ),rootFe(Ⅲ)chelatereductaseactivityisusuallymeasuredwithaspectrophotometerusingMES(2-morpholinoethanesulfonicacid)orHEPES(2-(4-(2-Hydroxyethyl)-1-piperazinyl)ethanesulfonicacid)bufferinthedarkbecauseofhighautoreductionrateofFe(Ⅲ)inthepresenceoflight.However,theexclusionoflightisinconvenient,especiallywhenanalyzingalargenumberofsamples.TheobjectiveofthisstudywastodevelopanewmethodfordeterminationofrootreductaseactivityundernormallaboratoryconditionsusingasuitablebuffercompositionandFe(Ⅲ)concentrationtoeliminatetheautoreductionofFe(Ⅲ).AmodifiedmethodusingaTris(2-amino-2-hydroxymethyl-1,3-propanediol)bufferatpH7.5insteadofMESorHEPESbufferandadecreasedFeEDTA(Feethylenediaminetetraaceticacid)concentrationof50μmolL-1wasdeveloped.TheautoreductionofFe(Ⅲ)usingtheTrisbufferwasundetectablefortemperaturesat4and28℃andwasalsomuchlowerthanthatusingtheotherbuffersevenwithsunlightduringmeasurementofFe(Ⅲ)reduction.Furthermore,thedifferencesinFe(Ⅲ)reductaseactivityamong5plantspeciesand14redclovercultivars(TrifoliumpratenseL.)couldbeeasilydetectedwiththemodifiedmethod.ThemethoddevelopedinthisstudytomeasurerootFechelatereductaseactivitywasnotonlyeffectiveandreliablebutalsoeasilymanagedundernormallaboratorylightconditions.

简介：Toshowthevegetationsuccessioninteractionwithsoilproperties,microbialbiomass,basalrespiration,andenzymeactivitiesindifferentsoillayers(0-60cm)weredeterminedinsixlands,i.e.,2-,7-,11-,20-,and43-year-oldabandonedlandsandonenativegrassland,inasemiaridhillyareaoftheLoessPlateau.Theresultsindicatedthatthesuccessionaltimeandsoildepthsaffectedsoilmicrobiologicalparameterssignificantly.In20-cmsoillayer,microbialbiomasscarbon(MBC),microbialbiomassnitrogen(MBN),MBC/MBN,MBCtosoilorganiccarbonratio(MBC/SOC),andsoilbasalrespirationtendedtoincreasewithsuccessionalstagesbutdecreasewithsoildepths.Incontrast,metabolicquotient(qCO2)tendedtodecreasewithsuccessionalstagesbutincreasewithsoildepths.Inaddition,theactivitiesofurease,catalase,neutralphosphatase,β-fructofuranosidase,andcarboxymethylcellulose(CMC)enzymeincreasedwithsuccessionalstagesandsoildepths.TheyweresignificantlypositivelycorrelatedwithmicrobialbiomassandSOC(P<0.5),whereasnoobvioustrendwasobservedforthepolyphenoloxidaseactivity.Theresultsindicatedthatnaturalvegetationsuccessioncouldimprovesoilqualityandpromoteecosystemrestoration,butitneededalongtimeunderlocalclimateconditions.

简介：Environmentalriskspertainingtocontaminatedsoilshavebeenwellstudied,whilelittleattentionhasbeenpaidtotherisksofthesoilsafterremediation.Inthisstudy,aconceptmodeldevelopedbasedonfuzzysettheorywasappliedtoevaluatetheuncertaintiesofthreeriskindicators,namely,plantgrowth,groundwatersafetyandhumanhealth,ofarestoredsitethathadbeenpreviouslypollutedbyheavymetals.Theconceptmodelclassifiedthegradeandimportanceofriskfactorsbyan11-levelrankingsystemandwasabletoyieldacomprehensiveriskresultratherthanmulti-riskresultsforcomplexriskindicators.Modelingresultsshowedthattheriskstothethreeindicatorswereeffectivelyreducedaftertheremediation.Moreover,greatsensitivityoftheriskswasfoundrelatedtotheweightdistributionamongthethreeriskindicators.Ingeneral,therisksofbothpollutedandrestoredsoilstotheenvironmentwereintheorderofgroundwatersafety>plantgrowth>humanhealth.Themodelwasprovedtosolvetheproblemsofmulti-riskresultsduetocomplexriskindicatorsthatpreviouslyencounteredbyotherresearchers,whichmadeithelpfulindecision-makingandmanagementofrestoredsoils.

简介：Vegetationfractionalcoverage(VFC)isoneofthekeyindicatorsofvegetationdistribution.Intheworkameasurement-basedmodelwasdevelopedtoderivetotalforestVFC(TG)aswellastheVFCoftrees(T)andshrub-grasses(G)separatelyinasubtropicalforestareainNanjing,China.Bothupwardanddownwardphotographsweretakenwithadigitalcamerain72quadrats(10m×10meach).Fifteenmodelswereestablishedandvalidated.ModelsjointlyusingbothTandGperformedbetterthanthoseusingtheTandGseparately.Thebestmodel,TG=T+G-1.134×T×G-0.025(R2=0.9115,P<0.01,rootmeansquarederror=0.0789),isrecommendedforapplication.ThismodelprovidesagoodwaytoobtaintotalforestVFCvaluesthroughtakingtreeandshrub-grassphotosongroundbelowtreecanopyratherthanabovetreecanopy.

简介：从最近在中国的香港以传统的方式进行的土壤调查基于遗产土壤数据，印射方法的数字土壤被使用为香港的山区生产土壤订购信息。二建模方法(决定树分析和线性判别式分析)被使用，并且他们的应用被比较。更多努力被放在为当模特儿选择土壤covariates上。首先，变化(ANOVA)的分析被用来测试在土壤订单之间的地面属性的变化。然后，一个逐步的过程被用来为线性判别式分析选择土壤covariates，并且一个向后的搬迁过程被开发为树建模选择土壤covariates。同时，印射的土壤上的ANOVA结果，以及我们的知识和经验，也为为树建模选择土壤covariates被考虑。二个线性判别式模型和四个树模型最后被建立，并且他们的预言表演用一条多重jackknifing途径被验证。结果证明在ANOVA结果上造的判别式模型最好表演了，由造由的判别式模型列在后面逐步，树模型由向后的搬迁过程，在印射的土壤上根据知识和经验造的树模型，和树造了自动地造的模型。结果强调了在为印射的土壤当模特儿选择土壤covariates的重要性，并且建议了在这研究使用选择土壤covariates的方法的实用性。最好的判别式模型最后被选择为这个区域印射土壤订单，并且确认结果显示出有的那张因此生产的土壤顺序地图高精确性。