简介：Effectofintermittentirrigationontheproductionofpaddyricewasstudiedinawell-puddledpaddyfieldwithfourtreatmentsand2replicates:continuoufloodingirrigation(CFI),andintermittentirrigationⅡ-0，Ⅱ-1andⅡ-2,inwhichplantswerere-irrigatedwhenthesoilwaterpotentialfellbelow0,-10,and-20toabout-10or-20kPadidnotsignificantlyaffectthenumberofgrainsandthepercentageofripenedgrains.While,alowercropgrowthrate(CGR)resultedfromadecreaseinthenetassimilationrate(NAR)duringintermittentirrigationⅡ-1andⅡ-2,andtherewasalsoareductionintheleafareaindex(LAI)durinindtermittentirrigationⅡ-2.SenescenceoflowerleavesonstemswaspromotedintreatmentsⅡ-1andⅡ-2attheripeningstage.Earlysenescenceatripeningstageandwaterstressaroundmiddaydecreasedtherateofphotosynthesisinleaves,causingthelowerNAR,Thesephysiologicalresponsesoftheplantswereresponsibleforthereductioninthedrymatterproductionandgrainyieldintheintermmittentirrigationtreatments.

简介：Elovich,two-constant,parabolicdiffusion,exponential,second-order,first-orderandzero-orderequationswereusedtodescribethekineticcharacteristicsofpotassiumdesorptionfromsixpaddysoilsofZhejiangProvinceinaconstantelectricfield(44.4V/cm)ofEUF.Resultsshowedthatthesecond-orderandElovichequationscoulddescribethepotassiumdesorptionkineticsbest,asevidencedbythehighestcorrelationcoefficients(r)andtheloweststandarderrors(SE).Thefirst-order,two-constantandparabolicdiffusionequationsalsodescribedtheKdesorptionkineticswell,asshowedbytherelativelyhighcorrelationcoefficientsandrelativelylowstandarderrors.Thezero-orderequationdidnotdescribetheKdesorptionsatisfactorilywitharelativelylowcorrelationcoefficientandrelativelyhighstandarderror.However,theexponentialequationcouldnotbeusedtodescribetheKdesorptionkinetics,duetothelowestcorrelationcoefficientandthehigheststandarderror.

简介：Soilswerecollectedfrom2-year(2-y)and3-year(3-y)oldred-pineseedlingplotsintwotreenurseries,HaywardinthenorthandWilsoninthesouthwesternpartofWisconsinStaterespectively,andequilibratedwith0.01MCa(NO3)2)forsoilsolutionZnandMn(solu-ZnandMn),andwith0.01MCa(NO3)2+0.005MEDTAforsoilabsorbedZnandMn(ad-ZnandMn).BufferingcapacityofsoilZnandMn(b-ZnandMn)wasobtainedfromtheratioofad-ZnandMntothesolu-ZnandMn.Theconcernedtracesinpineseedlingneedles(ndls),stems(sts)androots(rts)weresimultaneouslymeasured.Theresultsobtainedshowthat:About60%ofsolu-andad-Znrangedfrom0.2to0.4andfrom1to2μg/gsoilrespectively.About70%ofb-Znwaswithin3-10.Thehighestcontentofsolu-Zncomparedwiththelowestshowedadiscrepanceofmorethan10-fold.ThetwoformsofsoilZnwerecommonlyhigherinWilsonthaninHaywarkNursery.About80%ofsolu-,ad-andb-Mnwerewithin3-10,5-5.8μg/gsoiland1-2respectively.Influenceoflowbufferingcapacityonsolu-ZnandMnwasabout20timesstrongerthanthatofthehigh.TheE-value,aratioofaccumulatedZnandMninneedlestothoseinthesoilsolution,isprovedtobe:E-Zn>E-Mn;E-sts>E-ndlsorE-rts;andE-2y>E-3y.Curvilinearand/orlinearcorrelationsbetweensoilsolu-,ad-andb-ZnandMnandndls-,sts-,rts-ZnandMnwereatverysignificantorsignificantlevels.Forpredictingndls-ZnandMn,tworealizableandsimplemodelsfromtworegressionequationswereestablishedthroughtheselectionofrelatedparametersanddependentvariables.BinaryregressionanalysisbasicallyeliminatedtheinfluenceofsoilpHonthepredictionofZnandMninneedles.SoilpHwasthusthoughttobeexcludedfromthemodel.

简介：土壤的理解在野火或控制灼伤以后的热电导率是重要的打管理和火以后的恢复努力。尽管玷污热电导率很好被学习了因为非火加热了土壤，全面数据评估在土壤上的从火的极端加热的长期的效果热电导率被限制。这研究的目的是由直接比较在土壤的有效热传导性上评估火的长期的影响加热火的，没有火控制通过一系列实验室研究玷污。热传导性在Manitou试验性的福雷斯特，以内从二个地点为十件土壤样品被测量科罗拉多，美国，为到浸透的剩余度的从浸透的水内容的一个范围。测量的热传导性与用文学用三个实验模型做的独立估计相比，包括坎贝尔等。(1994)，C?t???????$

简介：Basedontheconceptionoffluidmechanics,thepaperpropoundsamodelformonthlypotentialevapotranspirationETi(mm):ETi=22di(1.6+Ui^1/2)woi(1-hi)/Pi^1/2(273.2+ti)^1/4whereiisthenumberofamonth,Pithemeanmonthlyatmosphericpressure(hPa),tithemeanmonthlyairtemperature(℃),dithenumberofdaysinthemonth,Uithemeanmonthlywindvelocitymeasuredatheight10-12m(m/s),woithesaturatedwatervapourpressureatti(mmHg,1mmHg=133.322Pa),andhithemeanmonthlyrelativehumidity.TheannualaridityKis:K=12∑i=1ETi/rawhereraisthemeanannualprecipitation(mm).Baseduponthedataof669sitesinChinaduring1951-1980,therelationsamongthesoilmoistureregime,thevegetationandthevalueofKmaybeillustratedasfollows:KSoilmoistureregimeVegetationK<1UdicFOrest1≤K<2semi-udicFroest,froest-steppeandsteppe2≤K<3.5Semi-aridicAridsteppe3.5≤K<11AridecDesert-steppeK≥11VeryaridicDesert.

简介：Alaboratorylysimeterexperimentwasconductedtoinvestigatetheeffectsofforagecorn(ZeamaysL.)stalkapplicationontheCO2concentrationinsoilairandcalcareoussodicsoilreclamation.Theexperimentaltreatmentstestedweresoilexchangeablesodiumpercentage(ESP)levelsof1,11,and19,addedcornstalkcontentsof0to36gkg-1,andincubationdurationsof30and60days.TheexperimentalresultsindicatedthatcornstalkapplicationandincubationsignificantlyincreasedCO2partialpressureinsoilprofileandloweredpHvalueinsoilsolution,subsequentlyincreasednativeCaCO3mineraldissolutionandelectrolyteconcentrationofsoilsolution,andfinallysignificantlycontributedtoreductiononsoilsodicitylevel.Thereclamationeffciencyofcalcareoussodicsoilsincreasedwiththeaddedcornstalk.Whencornstalkswereaddedattheratesof22and34gkg-1intothesoilwithinitialESPof19,itsESPvaluewasdecreasedby56%and78%,respectively,afterincubationof60daysandtheleachingof6.5porevolumes(about48Lofpercolationwater)withdistilledwater.Therefore,cropstalkapplicationandincubationcouldbeusedasachoicetoreclaimmoderatecalcareoussodicsoilsorasasupplementofphytoremediationtoimprovereclamationeffciency.

简介：Wetlandsoilqualitydegradationcausedbylarge-scaleagriculturalreclamationontheSanjiangPlainofNortheastChinahasbeenwidelyreported.Arelativesoilqualityevaluation(RSQE)modelandaprojectionpursuitevaluation(PPE)modelbasedonreal-codedacceleratinggeneticalgorithmwereintroducedtoevaluatequalityvariationsintoplayersofthemainwetlandsoilsontheSanjiangPlainin1999and2003,respectively.Assoilqualitydegradationboundarieswerevague,thisstudyestablishedtwofuzzysyntheticevaluation(FSE)modelsbasedontheoriginaldataandcriteriausedintheRSQEandPPEmodels.TheoutputsofthetwoFSEmodelswereobtainedbychoosingtwofuzzycompositeoperatorsM(∧,∨)andM(·,⊕).StatisticalanalysisshowedthattheresultsoftheFSE,RSQE,andPPEmodelswerecorrelated.Inparticular,outputsoftheFSEmodelusingM(·,⊕)weresignificantlycorrelatedwiththoseoftheRSQEmodelwithr=0.989atP<0.01.ComparedwithRSQEandPPEmodels,theFSEmodelmaybemoreobjectiveinshowingsoilqualityvariationsandwasclosertothenaturalsituation,showingthefeasibilityandapplicabilityoftheFSEmodelinevaluatingsoilqualitydegradation.However,thechoiceofcompositeoperatorwasofcriticalimportance.ThestudyofwetlandsoilqualitydegradationontheSanjiangPlainwasofscientificandpracticalsignificanceforprotectionandmanagementofsoilsandforsustainabledevelopmentofagricultureinthisareainthefuture.

简介：Soilsalinityandhydrologicdatasetswereassembledtoanalyzethespatio-temporalvariabilityofsalinizationinFengqiuCounty,HenanProvince,China,inthealluvialplainofthelowerreachesoftheYellowRiver.Thesalinesoilandgroundwaterdepthdataofthecountyin1981wereobtainedtoserveasahistoricalreference.Electricalconductivity(EC)of293surfacesoilsamplestakenfrom2km×2kmgridsin2007and40soilprofilesacquiredin2008wasanalyzedandusedforcomparativemapping.OrdinarykrigingwasappliedtopredictECatunobservedlocationstoderivethehorizontalandverticaldistributionpatternsandvariationofsoilsalinity.Groundwatertabledatafrom22observationwellsin2008werecollectedandusedasinputforregressionkrigingtopredictthemaximumgroundwaterdepthofthecountyin2008.ChangesinthegroundwaterlevelofFengqiuCountyin27yearsfrom1981to2008wascalculated.Twoquantitativecriteria,themeanerrororbias(ME)andthemeansquarederror(MSE),werecomputedtoassesstheestimationaccuracyofthekrigingpredictions.Theresultsdemonstratedthatthesoilsalinityintheuppersoillayersdecreaseddramaticallyandthetaxonomicallydefinedsalinesoilswerepresentonlyinafewmicro-landscapesafter27years.Presently,thesoilswithrelativelyelevatedsaltcontentweremainlydistributedindepressionsalongtheYellowRiverbed.Thereductioninsurfacesoilsalinitycorrespondedtothelocationswithdeepenedmaximumgroundwaterdepth.Itcouldbeconcludedthatgroundwatertablerecessionallowedwatertomovedeeperintothesoilprofile,transportingsaltswithit,andthusplayedanimportantroleinreducingsoilsalinityinthisregion.Accumulationofsaltsinthesoilprofilesatvariousdepthsbelowthesurfaceindicatedthatsecondarysoilsalinizationwouldoccurwhenthegroundwaterwasnotcontrolledatasafedepth.

简介：Someelectrochemicalproperties,suchaspH,Eh,andvoltammetricbehavior.ofthedecompositionproductsofricestrawandtheinteractionsoftheseproductswithsoilswerestudied.ThepH,Eh,andamountsoforganicreducingsubstanceschangedmarkedlyduringthe6-dayanaerobicdecomposition.pHdecreasedsharplytopH5onthetenthdayandthenincreasedgraduallyto7onthe45rhday.Theamountsoforganicreducingsubstancesincreasedalmostsynchronouslywiththefallofredoxpotentialduringthefirst15days.Thedifferentialpulsevoltammetric(dpv)behaviorchangednotonlyinthepeakcurrentbutalsointhepeakpotential.Thefractionswithapparentmolecularweightslowerthan200daltonsappearedtobeactiveindpvbehavior.Theelectricchargeandpositivelycharged,respectively.Thegroupwithalowapparentmolecularweightandanegativechargewasthemaincomponentsresponsiblefortheloweranodicpeakpotentials.Theywereoxidizedfirstduringtheinteractionsoftheorganicreducingsubstanceswithsoils.

简介：PhysiographyandsoilinMaeRimwatershed,ChiangMaiProvince,Thailandwereinvestigatedbyusingaerialphotographsandsatelliteimageinconjunctionwithfieldwork,andsoilinfiltrationrateandsoilshearresistanceweremeasuredinfield.ManyfactorsaffectingrunoffwereanalyzedusigtheIntegratedLandandWaterInformaitonSystem(ILWIS).Asaresult,amodeldeterminingfloodhazarwassetup.Threempsincludingrunoffcurvenumbermap,runoffcoefficentmap,andfloodinumdationmapwerecreated,Inaddition,thetimeofconcentrationwaspredicted.