简介：Amodelforsimulatingcadmiumtransportinasoil-plantsystemwasbuiltusingacommercialsimulatingprogramnamedPowersimonthebasisofinput-outputprocesseshappeninginthesoil-plantsystem.COnvectiveanddispersivetransportprocessesofcadmiuminsoilprofileareembedded.Simulationsonadailybasehavebeendoneuptoatotalsimulatingtimeof250years,Resultsshowthatapplicationsofsewagesludgeandfertilizeratthesimulatedrateswouldonlycauseslightcadmiumaccumulationsineachlayerofthesoil,andcadmiumaccumulationwouldbelevellingoff,reachinganequilibriumconcentrationslayerbylayerdownwardaftercertaintime.Thetimescaletoreachanequilibriumconcentrationvariesfrom10yearsforthetopthreelayerstoover250yearsforthebottomlayers.Plantcadmiumuptakewouldincreasefrom52umm^-2underinitialsoilcadmiumconcentrationsto65ugm^-2underequilibriumsoilcadmiumconcentrations,whichwouldnotexceedthemaximumallowablecadmiumconcentrationinwheatgrains.Mainparameterswhichinfluencecadmiumaccumulationandtransportinsoilaretotalcadmiuminput,rainfall,evaporation,plantuptakeandsoilproperties.

简介：Methaneoxidationbypaddysoilsinaclosedsystemcouldbesimulatedbytheequationx=k1xo/(k1+k2x0)exp(k2t)-k2x0wherex0andxaretheCH4concentrationsattimezeroandt,respectively;k1andk2areconstantsrelatedtotheconstantoffirst-order-kinetics.AccordingtotheequationthechangeofsoilabilitytooxidizeCH4couldbeestimatedbytheequationAc=k2/k1(x0-x)x0k2/k1-1.TheresultsshowedthatthesoilabilitytooxidizeCH4varied,dependingontheinitialCH4concentration.HighinitialCH4concentrationstimulatedsoilabilitytoconsumeCH4,whilelowconcentrationdepressedtheablility.Thischaracteristicofpaddysoilseemedtobeofconsiderablesignificancetoself-adjustingCH4emissionfromfloodedricefieldsifthereexistoxicmicrositesinthesoil.

简介：Amini-plotfieldexperimentwasconductedonaloamyclayOxisoltocompareandevaluatePabsorptionandtransferinplantorgansandPmovementinsoilprofileatthreePapplicationdepthsunderthesoybean-citrusintercroppingversusthemonocultureusinga32Ptracertechnique.TotalPabsorption(Pt)bysoybeanandPaccumulation(Pa)insoybeanorgansdecreasedsignificantly(P<0.05)undertheintercroppingincontrasttothemonoculture.Withintercropping,when32Pwasappliedintopsoil(15cmsoillayer),total32Pabsorption(32Pt)insoybeanswassignificantlylower(P<0.05),butwhen32Pwasappliedtodeepersoillayers(35or55cmsoillayer),32Ptinsoybeanswassignificantlygreater(P<0.05).ThepercentageofPinleavestototalP(Pa/Pt)and32Pinleavestototal32P(32Pa/32Pt)forsoybeanwere(?)25%andthoseofroot(?)12%.WhenPwasappliedintopsoiland55cmsoillayer,nosignificantdifferenceswerefoundbetweenintercroppingandmonocultureforPtofcitrus.ThePabsorbedbycitruswastransferredrapidlytothegrowingorgansofabovegroundduringtheexperiment,andthespeedoftransferringtothegrowingorgansslowedwhenPwasappliedtothedeepersoillayers.Inintercropping,Pmobilitywasheightenedinthesoilprofile,andPindeepersoillayersmoveduptotopsoilmorerapidly.

简介：化肥氮(N)的高率在东南的中国在温室蔬菜地里被使用最大化生产；然而，如此的集中的蔬菜生产的N预算尚待被探索。这研究的目标是以五N(脲)应用程序率(0，348，522，696，和870kgNha1year1)在西红柿，黄瓜，和芹菜的年度旋转的一个温室蔬菜系统决定年度N平衡和损失。到050厘米土壤层的全部的N输入从531～1053kgha1，并且N化肥是主要N来源，为全部的年度N输入的66%83%的财务。在比较，总共的灌溉水，湿免职，和种子占了不到1%全部的N输入。化肥N使用效率仅仅在870kgNha1的常规申请率下面是18%并且当申请率从522～870kgNha1增加了，减少了。明显的N损失是196201kgNha1，71%86%被以522870kgNha1的申请率沥滤失去。因此，沥滤是以高N申请率的主要N损失小径，N的数量沥滤与在黄瓜季节期间使用的N成正比。而且，溶解器官的N说明了10%沥滤的N，而NH3挥发仅仅在五N下面贡献了明显的N损失的0.1%0.6%，申请在这个温室蔬菜系统评价。

简介：RedsoilisaveryimportantsoilresourceinsouthernChina.However,duetobeingsimultaneouslyofhighproductivepotentialitiesandseverelydegraded,itneedsharnessingurgently.RedSoilResourceInformationSystem(RSRIS)basedonremoltesensingandgeographicinformationsystem(GIS)playsanimportantroleinsurvey,evaluation,utilziationandmanagementofredsoilresource.RSRISofQuzhouCity,ZhejiangProvince(1:250000)andRSRISofLongyouCounty,ZhejiangProvince(1:50000)havebeenmaderespectivelyonSUNSPARCstationandusingRC/INFO.Thispaperintroducesthesystemdesign,databsecreationandsystemfunctions,anditparticularlyfocusesondevelopingappliedmodels,suchasredsoilresourcedivisonandmapping,suitabilityevaluation,erosionriskevaluation,plantutilizationzoneetc.TheproblemsonstudyofRSRISanditsdevelopingstrategyarealsodiscussed.

简介：Changesofsoilorganicnitrogenformsandsoilnitrogensupplyundercontinuousricecroppingsystemwereinvestigatedinalong-termfertilizationexperimentinJinhua,ZhejiangProvince,China.ThefertilizertreatmentsincludedcombinationofP-K,N-K,N-P,andN-P-Kaswellasthecontrol.Aftersixyearsofcontinuousdouble-ricecropping,totalsoilNandhydrolysableNcontentsremainedstableinplotswithNtreatments,whilethehydrolysableNcontentsweresubstantiallyreducedinthoseplotswithoutNapplication.Comparedtotheunbalancedfertilizationtreatments,PandKincreasedthepercentageofhydrolysableammoniumNinthetotalsoilNwiththebalancedapplicationofN,andalsomaintainedhigherricegrainyieldsandnitrogenuptake.GrainyieldwaspositivelycorrelatedwithtotalNuptake(r=0.875**),hydrolysableN(r=0.608**),hydrolysableammoniumN(r=0.560**)andthehydrolysableunknownN(r=0.417**).TotalNuptakewaspositivelycorrelatedwithhydrolysableN(r=0.608**),hydrolysableammoniumN(r=0.440**)andhydrolysableunknownN(r=0.431**).Soilnutrientdepletionand/orunbalancedfertilizationtoricecropreducedNcontentinsoilmicrobialbiomass,andthereforeincreasedC/Nratio,suggestinganegativeeffectonthetotalmicrobialbiomassinthesoil.

简介：polyolefin涂的脲的有效性(Meister-5和Meister-10；CU)在小麦(TriticumaestivumL.)玉米(ZeamaysL.)旋转系统在为收割季节的三连续maize-wheat-maize位于北方中国平原的溶度计阴谋被学习。一个同位素的方法被用来把CU的命运比作非涂的脲(NCU)的，并且N申请0，100，150和225kgNha−1评价被评估。结果证明CU的氮使用效率(15NUE)是比为第一庄稼的NCU的大的13.3%–21.4%。或者，当差别方法被使用时(明显的NUE)，没有重要变化在所有三个季节在处理之中被观察。尽管无机的N从1.3m层沥滤，不到1%总数被使用N，15N的未辩别出的损失(=15N作为化肥–15N使用了的15N的损失由留在0–0.2m层–15N的庄稼–15N吸收了从1.3m层沥滤)在对待CU的阴谋是24.2%–26.5%比那些低对待NCU的阴谋。在在实验的结束的CU阴谋的0–1.3m层的硝酸盐集中是53%比对待NCU的阴谋的低。因此，CU从化肥增加了庄稼N举起并且减少了应用N的未辩别出的损失，它能减少地下水污染的风险。

简介：印射土壤硝酸盐氮(NO3-N)的空间分发是重要的指导氮申请以及估计沥滤进地下水的NO3-N的环境风险。我们采用了univariate和混合geostatistical方法在东北佛罗里达越过一处风景印射土壤NO3-N的空间分发。土壤样品从四深度增长被收集(030，3060，60120和120180厘米)基于土壤，土地使用和举起阶层从用成层的随机识别并且嵌套采样的147个采样地点设计。在二层是的顶的土壤NO3-N分布空间地，汽车相关并且印射使用木头正常kriging。为NO3-N预言的环境关联模型用线性、非线性的回归方法被导出，并且采用了开发NO3-N趋势地图。陆地使用和它从卫星形象导出的相关变量作为重要变量被识别用环境关联模型预言NO3-N。当木头正常kriging生产了顺利变化的地图时，从环境关联模型导出的趋势地图产生了空间地异构的地图。趋势地图与趋势模型剩余的平常的kriging预言被相结合开发回归kriging预言地图，它给了最好的NO3-N预言。因为土地使用和遥远地察觉到的数据是容易地可得到的并且有大部分，与地相比的更好的空间分辨率取样了土壤，我们的调查结果基于为风景的使用和遥远地察觉到的数据放大土壤NO3-N印射的土地建议了环境关联模型的功效。实现的方法论为在另外的风景土壤NO3-N印射是可转让的。

简介：Integrationofsoilinformationsystem(SIS)andinteractiveself-organizingdata(ISODATA)wasstudiedtoestablishproperagriculturaldevelopingzonesinredsoilregionofsouthernChinawhichareofcrucialimportancetofarmers,researchers,anddecisionmaderswhileutilizingandmanagingredsoilresources.SIScreatedbyusingARC/INFOwasusedtoprovidedataacquisition,systematicmodelparameterassignment,andvisualdisplayofanalyticresults.Topography,temperature,soilcomponent(e.g.,organicmatterandpH)andconditionofagriculturalproductionwereselectedasparametersofISODATAmodel.TakingLongyouCounty,ZhejiangProvinceasthecasestudyarea,theeffectoftheintegrationandrecommendationsarediscussedforfutureresearch.

简介：Thelowremovaleffciencyoftotalnitrogen(TN)isoneofthemaindisadvantagesoftraditionalsinglestagesubsurfaceinfiltrationsystem,whichcombinesananaerobictankandasoilfilterfield.Inthisstudy,afull-scale,two-stageanaerobictankandsoiltrenchsystemwasdesignedandoperatedtoevaluatethefeasibilityandperformancesintreatingsewagefromaschoolcampusforoveraone-yearmonitoringperiod.Therawsewagewaspreparedandfedintothefirstanaerobictankandsecondtankby60%and40%,respectively.Thisnovelprocesscoulddecreasechemicaloxygendemandwiththedichromatemethodby89%-96%,suspendedsolidsby91%-97%,andtotalphosphorusby91%-97%.Thedenitrificationwassatisfactoryinthesecondstagesoiltrench,sotheremovalsofTNaswellasammonianitrogen(NH+4-N)reached68%-75%and96%-99%,respectively.ItappearedthattheremovaleffciencyofTNinthistwo-stageanaerobictankandsoiltrenchsystemwasmoreeffectivethanthatinthesinglestagesoilinfiltrationsystem.Theeffuentmetthedischargestandardforthesewagetreatmentplant(GB18918-2002)ofChina.

简介：Soilqualityassessmenthasbeensuggestedasaneffectivetoolforevaluatingsustainabilityofsoilandcropmanagementpractices.Theobjectiveofthisstudywastodevelopasensitivesoilqualityindex(SQI)basedonbulkdensity(BD),water-holdingcapacity(WHC),water-stableaggregates(WSA),aggregatemeanweightdiameter(AMWD),totalorganicC(TOC)andCinputtoevaluatetheimportantrice-wheatcroppingsystemonanInceptisolinIndia.Along-termexperimenthasbeenconductedfor18yearsattheIndianCouncilofAgriculturalResearch-IndianInstituteofFarmingSystemsResearch,Modipuram,India.Thetreatmentsselectedforthisstudywerecomprisedofano-fertilizercontrolandN,PandKfertilizers(NPK)combinedwithZnandSfertilizers(NPK+Zn+S),farmyardmanure(NPK+FYM),greengramresidues(NPK+GR)andcerealresidues(NPK+CR),laidoutinarandomizedcompleteblockdesignwiththreereplications.SoilsampleswerecollectedandanalyzedforBD,WHC,WSAandTOC.Correlationanalysisrevealedthatbothriceandwheatyieldssigni?cantlyincreasedwiththeincreasesinAMWD,TOCandCinput,butdecreasedwiththeincreaseinBD.TheSQIvalueswerethengeneratedbasedonregressionanalysisofBD,WSA,AMWD,TOCandCinputwithriceandwheatyieldsforthe0–15and15–30cmsoillayers,respectively.RegressionanalysesbetweencropyieldsandSQIvaluesshowedaquadratictypeofrelationwiththecoeffcientofdetermination(R~2)varyingfrom0.78to0.89.Withregardtosoilsustainability,applyingcropresiduestobothriceandwheatcouldmaintainsoilqualityforalongerperiod,whereasthehighestyieldsofboththecropswererecordedintheNPK+Zn+Streatment.Theregressionequationsdevelopedinthisstudycouldbeusedtomonitorsoilqualityinasubhumidtropicalrice-wheatcroppingsystem.

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