简介：Atelevatedtemperatureregimesandabundantprecipitation,mobilizationandaccretionofweatheredironoxidesarepromotedespeciallyinareducedenvironmentsinthetropics.Thismayleadtotheformationofplinthite,whichhardensirreversiblyuponrepeatedwettinganddryingtoformpetroplinthite.Theneedforthisreviewstemsfromtheseeminglydearthofinformationonthesubjectandaneedtoclarifydifferenttermsusedindescribingplinthite.Wereviewvariousresearchworksonplinthiteanditsassociatedpedogenicformsinthetropics.Furthermore,weprofferrecommendationsastothemostappropriatelandusemanagementpracticesthatcouldhelpminimisetheenvironmentalandagronomicproblemsassociatedwithplinthiteanditsrelatedpedogenicforms.Parentmaterial,temperature,seasonalityandgeomorphologyarecriticalfactorsthatinfluencesoilwaterregimewhichinturnaffectthepedogenesisofplinthite.SoilpHandmineralogyareadditionalfactorsthatcouldalsopromoteplinthiteformation.Fossilplinthicsoilsarepotentialproxiesforpalaeoenvironmentalreconstruction.Measuresusedinthemanagementofplinthicsoilsincludemechanicallybreakingthehardpansandtheuseoforganicandinorganicamendmentstomodifythestructureandchemistryofthesoils.Avoidanceofpracticesthatwouldpredisposesoilstoerosionwouldalsopreventplinthization.Wecallfortherelinquishmentoftheterm'laterite'whichisageneraltermforallformsofironoxide-enrichedearthymaterialsasusedforplinthite.PlinthichorizonshouldalsobeincorporatedintotheUnitedStatesDepartmentofAgricultureSoilTaxonomyinviewofitsgrowingimportanceinsoils.

简介：Along-termexperimentbeginningin1981inJinxianCountyofJiangxiProvince,subtropicalChina,wasconductedinapaddyfieldunderadoublericecroppingsystemwithfourdifferentfertilizationregimes,including1)nofertilizerascontrol(CK),2)balancedchemicalN,P,andKfertilizers(NPK),3)organicmanureusingmilkvetchandpigmanureintheearlyandlatericegrowingseason,respectively(OM),and4)balancedchemicalfertilizerscombinedwithorganicmanure(NPKM).Samples(0-17cm)ofthepaddyfieldsoil,whichwasderivedfromQuaternaryredclay,werecollectedafterthelatericeharvestinNovember2003fordeterminationoftotalorganiccarbon(TOC)andtotalnitrogen(TN)andfractionsoforganicCandN.ResultsshowedthatTOCandTNintheNPKMandOMtreatmentsweresignificantlyhigherthanthoseinothertwotreatments(CKandNPK).ApplicationoforganicmanurewithorwithoutchemicalfertilizerssignificantlyincreasedthecontentsofallfractionsoforganicCandN,whereaschemicalfertilizerapplicationonlyincreasedthecontentsofoccludedparticulateorganicC(oPOC)andaminoacidN.Inaddition,applicationoforganicmanuresignificantlyenhancedtheproportionsoffreeparticulateorganiccarbon(fPOC)andoPOCintotalC,andthoseofaminosugarNandaminoacidN(P<0.01)intotalN.Incontrast,chemicalfertilizerapplicationonlyincreasedtheproportionsofoPOCandaminoacidN(P<0.05).TherewerenosignificantdifferencesineithercontentsorproportionsofsoilorganicCandorganicNfractionsbetweentheNPKMandOMtreatments.TheseindicatedthatorganicmanureapplicationwithorwithoutchemicalfertilizersplayedthemostsignificantroleinenhancingsoilorganicCandNquantityandqualityinthepaddyfieldstudied.

简介：An80-dincubationexperimentwasconductedtoinvestigatestrawdecomposition,theprimingeffectandmicrobialcharacteristicsinanon-fertilizedsoil(soil1)andalong-termorganicmanure-fertilizedsoil(soil2)withandwithout13C-labeledmaizestrawamendmentunderdifferentmoisturelevels.Thesoil2showedamarkedlyhigherprimingeffect,microbialbiomassC(Cmic),andβ-glucosidaseactivity,andmoreabundantpopulationsofbacteriaandfungithanthesoil1.Also,soilCO2emission,Cmic,β-glucosidaseactivity,andbacterialandfungalpopulationsizesweresubstantiallyenhancedbystrawamendment.Inthepresenceofstraw,theamountofstrawmineralizationandassimilationbymicrobesinthesoilat55%ofwaterholdingcapacity(WHC)weresignificantlyhigherby31%and17%,respectively,comparedtothoseat25%ofWHC.Incontrast,β-glucosidaseactivityandfungalpopulationsizewerebothenhancedasthemoisturecontentdecreased.Cmicdecreasedasstrawavailabilitydecreased,whichwasmainlyattributedtothereductionofstraw-derivedCmic.Amendedsoils,excepttheamendedsoil2at25%ofWHC,hadamoreabundantfungalpopulationasstrawavailabilitydecreased,indicatingthatfungaldecomposabilityofaddedstrawwasindependentofstrawavailability.Non-metricmultidimensionalscalinganalysisbasedonfungaldenaturedgradientgelelectrophoresisbandpatternsshowedthatshiftsinthefungalcommunitystructureoccurredaswaterandstrawavailabilityvaried.Theresultsindirectlysuggestthatsoilfungiareabletoadjusttheirdegradationactivitytowaterandstrawavailabilitybyregulatingtheircommunitystructure.

简介：A15-yearfertilizationexperimentwithdifferentapplicationsofinorganicN,PandKfertilizersandfarmyardmanure(M)wasconductedtostudytheyieldandsoilresponsestolong-termfertilizationatQiyang,HunanProvince,China.Averagegrainyieldsofwheatandcorn(1672and5111kgha-1,respectively)forthetreatmentNPKMweresignificantlyhigherthanthose(405and310kgha-1)oftheunfertilizedcontrolandsingleinorganicfertilizertreatments.Comparedwiththecorrespondinginitialvaluesoftheexperiment,alltreatmentsshowedayielddeclineof9to111kgha-1year-1inwheatand35to260kgha-1year-1incorn,respectively,andasignificantpHdeclineof0.07to0.12pHyear?1,exceptforthetreatmentsPKandNPKM.Afterlong-termfertilization,thesoilorganicC,soilavailableP,exchangeableCa2+andMg2+andavailableCu2+andZn2+contentswerehigherinthetreatmentNPKMthaninthetreatmentsappliedwithinorganicfertilizeronly.ComparedtothetreatmentNPK,thetreatmentNPKM,wheremanurepartiallyreplacedinorganicN,hadapositiveimpactonarrestingthedeclineofsoilpH.Thisimprovedgrainyieldsofwheatandcorn,suggestingthatapplicationofNPKfertilizerincombinationwithfarmyardmanureisimportanttomaintainsoilfertilityandbufferingcapacityinredsoil.

简介：与一个改编微生物引起的社区接种土壤比有在bioremediation的纯紧张的接种是一条更有效的bioaugmentation途径。然而，从有在土壤补习改变污染层次和污染历史的地点的不同inocula的潜力的信息正在缺乏。学习的目的是在土壤inocula调查改编微生物的潜力，与不同污染层次和污染历史，到降级1,2,4-trichlorobenzene(1,2,4-TCB)。从污染chlorobenzene的地点的三不同土壤被接种进农业土壤和与1,2,4-TCB刺的土壤暂停文化。结果证明36.52%开始应用的1,2,4-TCB在非接种的土壤是在场的，而大约19.00%1,2,4-TCB在在28天孵化以后与污染土壤接种的农业土壤是在场的。与改编微生物引起的生物资源接种的土壤(在土壤inocula)比非接种的土壤显示出更高的呼吸和更低的1,2,4-TCB挥发，建议1,2,4-TCB的存在在为接种使用的污染土壤改编了degraders。它进一步在污染土壤暂停文化被证实无机的氯化物离子的集中在全部试验性的时期上连续地增加了。更高的降级潜力带到不仅而且到更高的残余形成的inocula的更高的污染。然而，甚至低级污染的inocula在提高1,2,4-TCB的降级是有效的。因此，适用改编了在土壤形式的微生物特别与更低的污染层次，inocula能是为土壤补习的有效、环境友好的策略。

简介：作为常规授精的一种选择评估器官的修正案的使用，沃土土壤的一个10年的实验在在Guadalquivir河山谷与化肥(NPK)和植物的堆肥(器官的化肥)使用的温室和室外的阴谋在一个庄稼旋转系统下面被进行，西班牙。土壤上的这二不同授精政体的效果物理性质被评估。玷污器官的碳(OC)，土壤体积密度(BD)，土壤水保留(WR)，可得到的水内容(AWC)，总数稳定性(作为)，并且玷污物理质量(德克斯特的索引，S)被决定。器官的化肥的使用增加了OC并且导致了的重要增加作为并且在与在温室和室外的阴谋的矿物质化肥申请相比的BD的减少。而温室阴谋出现了，室外的阴谋显示出最低BD价值象价值最高。在10年的实验的最后年里，S参数在器官的化肥阴谋是显著地更高的，特别为温室阴谋。在学习经期的结束，在在在在两个系统的治疗之间的领域能力(FC)的WR没有重要差别；AWC在矿物质在温室阴谋，但是更高也是类似的室外的阴谋。在矿物质化肥处理，在物理性质的小改进也与以前的集中的收割系统相比由于不太好攻击的耕种的利用被观察。物理土壤性质与土壤OC被相关。持续管理技术象器官的修正案的使用那样并且低或没有耕种改进了土壤物理性质，尽管有在管理的差别，那显著地逻辑地影响了结果。

简介：Theclosed-jarincubationmethodiswidelyusedtoestimatethemineralizationofsoilorganicC.TherearetwoCpools(i.e.,organicandinorganicC)incalcareoussoil.ToevaluatetheeffectofadditionalcarbonatesonCO2emissionfromcalcareoussoilduringclosed-jarincubation,threeincubationexperimentswereconductedbyaddingdifferenttypes(CaCO3andMgCO3)andamountsofcarbonatetothesoil.TheadditionofcarbonatessignificantlyincreasedCO2emissionfromthesoil;theincreaserangedfrom12.0%intheCaCO3amendedsoilto460%intheMgCO3amendedsoilduringa100-dincubation.CumulativeCO2productionattheendoftheincubationwasthreetimesgreaterintheMgCO3amendedsoilcomparedtotheCaCO3amendedone.TheCO2emissionincreasedwiththeamountofCaCO3addedtothesoil.Incontrast,CO2emissiondecreasedastheamountofMgCO3addedtothesoilincreased.Ourresultsconfirmedthattheclosed-jarincubationmethodcouldleadtoanoverestimateoforganicCmineralizationincalcareoussoils.BecauseofitseffectonsoilpHandthedissolutionofcarbonates,HgCl2shouldnotbeusedtosterilizecalcareoussoiliftheexperimentincludesthemeasurementofsoilCO2production.

简介：在空气在农业土壤影响土壤质量和温室气体集中在土壤改变器官的碳(SOC)。干燥农田在中国盖住超过70%整个农田区域并且在减轻二氧化碳(CO2)起一个重要作用排出物。在这研究，4109个干燥农田土壤多角形用土壤层的空间覆盖分析被提取(1:500000)并且陆地使用层(1:500000)在安徽为干燥农田支持SOC动力学的世纪模型模拟省，从1980～2008的华东。就二个地确认地点而言，世纪模型在在省为干燥农田为SOC动力学建模相对表演了很好。模仿的结果证明区域加权的平均数玷污从18.77MgCha−增加的干燥农田的器官的碳密度(SOCD)；1在1980～23.99MgCha−；10.18MgCha−与平均隐遁在2008评价；1year−；1。约94.9%全部的干燥农田区域扣押了碳当5.1%有的碳输了时。在过去的29年，在省的干燥农田土壤的网SOC获得是19.37Tg，与0.67TgCyear−的平均隐遁率；1。SOC的扩大主要由于氮化肥和农家庭院粪肥的增加的消费。而且，SOC动力学高度在干燥农田土壤组之中被区分。有一条好规模的土壤数据库途径的世纪模型的集成能方便地在地区性的规模为SOC动力学的精确模拟作为一个工具被利用。

简介：

简介：在空间插值以内集成陆地使用类型和另外的地理信息作为一个答案被建议了改进土壤营养素在地区性的规模印射的表演和精确性。这研究开发了一条非算法途径，即，到单个土地使用类型而非到整个分水岭，适用的反的距离weighting(IDW)和平常的kriging(好)总计C(TC)决定这是否在印射土壤改进了表演，总计N(TN)，并且在在东南中国城市化分水岭的200-km2总计P(TP)。四种陆地使用类型被视觉解释作为森林土地，农业陆地，绿陆地，和城市的土地识别。150件土壤样品(0-10厘米)根据陆地使用类型和补丁尺寸被拿。结果证明非算法来临，基于单个土地，使用打的插值，实质地为在分水岭印射TC，TN，和TP改进了IDW和好的表演。根均方差被3.9%为TC减少，10.7%为TN，并且25.9%为由IDW的应用程序的TP当由好的改进为TC作为0.9%稍微更低时，7.7%为TN，并且18.1%为TP。基于单个土地，使用视觉上打的插值由整个分水岭相对插值在分水岭为TC，TN，和TP改进了空间模式的描写。实质的改进可能与更稠密的采样点被期望。我们建议这条非算法途径可能提供一种选择给基于算法的途径描绘分水岭规模营养素模式。

简介：Soilmicrobialbiomassandcommunitystructuresarecommonlyusedasindicatorsforsoilqualityandfertility.Ainvestigationwasperformedtostudytheeffectsoflong-termnaturalrestoration,cropping,andbarefallowmanagementsonthesoilmicrobialbiomassandbacterialcommunitystructuresindepthsof0–10,20–30,and40–50cminablacksoil(Mollisol).Microbialbiomasswasestimatedfromchloroformfumigation-extraction,andbacterialcommunitystructuresweredeterminedbyanalysisof16SrDNAusingpolymerasechainreaction-denaturinggradientgelelectrophoresis(PCR-DGGE).Experimentalresultsshowedthatmicrobialbiomasssignificantlydeclinedwithsoildepthinthemanagementsofrestorationandcropping,butnotinthebarefallow.DGGEprofilesindicatedthatthebandnumberintop0–10cmsoilswaslessthanthatindepthof20–30or40–50cm.Thesesuggestedthatthemicrobialpopulationwashighbutthebacterialcommunitystructurewassimpleinthetopsoil.ClusterandprinciplecomponentanalysisbasedonDGGEbandingpatternsshowedthatthebacterialcommunitystructurewasa?ectedbysoildepthmoreprimarilythanbymanagements,andthesuccessionofbacterialcommunityasincreaseofsoildepthhasasimilartendencyinthethreemanagements.FourteenpredominatingDGGEbandswereexcisedandsequenced,inwhich6bandswereidentifiedasthetaxaofVerrucomicrobia,2bandsasActinobacteria,2bandsasα-Proteobacteria,andtheother4bandsasδ-Proteobacteria,Acidobacteria,Nitrospira,andunclassifiedbacteria.Inaddition,thesequencesof11DGGEbandswerecloselyrelatedtounculturedbacteria.Thus,thebacterialcommunitystructureinblacksoilwasstable,andthepredominatingbacterialgroupswereuncultured.

简介：Bt玉米叶垃圾的化学作文上的基因修正的非计划中的效果可以在它的分解上有影响。在在南非的很农业的系统，玉米垃圾是任何一个留在土壤表面上或在耕种期间合并了到土壤。用三个玉米混血儿(DKC80-12B，DKC80-10和DKC6-125)的叶垃圾，一个litterbag实验在堡垒兔研究农场的大学被执行，南非，为了在玉米叶的分解上决定基因修正的效果，乱丢东西什么时候在在7月和11月之间的地条件下面留在土壤表面上，正常休闲时期，在2008。另一个litterbag实验在堡垒兔研究农场的大学被进行，使用南非遗传上与cry1Ab修改了的二个玉米混血儿的叶垃圾并且Zanyokwe灌溉计划，基因(MON810)，DKC75-15B和PAN6Q-308B，和他们的相应近的isolines，CRN3505和PAN6Q-121。在崽的Cry1Ab蛋白质的降级，适用表面、合并土壤，也被调查。当在表面上适用时并且当合并了到土壤时，Bt玉米垃圾的分解类似于non-Bt玉米垃圾的。合并土壤的垃圾，以及它的Cry1Ab蛋白质，比在表面上适用的快分解了。叶崽C:PAN6Q-308B和PAN6Q-121的N比率在整个学习是类似的，而那些在一个12星期的时期期间由类似的数量DKC75-15B和CRN3505衰退了。这些调查结果建议与MON810事件，Bt玉米的叶垃圾的那分解没被玉米影响基因修正，并且Cry1Ab蛋白质不管崽是否在土壤表面上被使用或合并了到土壤在冬季休闲期间和植物叶垃圾垮掉。

简介：Itisgloballyacceptedthatsoilcarbon(C)dynamicsareatthecoreofinterlinkedenvironmentalproblems,deterioratingsoilqualityandchangingclimate.Itsmanagementremainsacomplexenigmaforthescientificcommunityduetoitsintricaterelationshipwithsoilnitrogen(N)availabilityandmoisture-temperatureinteractions.ThisarticlereviewsthemanagementaspectsofsoilCdynamicsinlightofrecentadvances,particularlyinrelationtotheavailabilityofinorganicNpoolsandassociatedmicrobialprocessesunderchangingclimate.Globally,drasticalterationsinsoilCdynamicsunderchanginglanduseandmanagementpracticeshavebeenprimarilyattributedtothevariationinsoilNavailability,resultinginahigherdecompositionrateandaconsiderabledeclineinsoilorganicC(SOC)levelsduetoincreasedsoilCO_2emissions,degradedsoilquality,andincreasedatmosphericCO_2concentrations,leadingtoclimatewarming.PredictedclimatewarmingisproposedtoenhanceSOCdecomposition,whichmayfurtherincreasesoilNavailability,leadingtohighersoilCO_2efflux.However,aliteraturesurveyrevealedthatsoilmayalsoactasapotentialCsink,ifwecouldmanagesoilinorganicNpoolsandlinkmicrobialprocessesproperly.Studiesalsoindicatedthattherelative,ratherthantheabsolute,availabilityofinorganicNpoolsmightbeofkeyimportanceunderchangingclimate,astheseNpoolsarevariablyaffectedbymoisture-temperatureinteractions,andtheyhavevariableimpactsonSOCturnover.Therefore,multi-factorialstudiesarerequiredtounderstandhowtherelativeavailabilityofinorganicNpoolsandassociatedmicrobialprocessesmaydetermineSOCdynamicsforimprovedsoilCmanagement.

简介：Nutrient-poor,sandysoilsformtheprevailingsubstrateatpost-miningsitesoftheLusatianregion(Brandenburg,Germany)andpresentachallengeforvegetationdevelopment.Westudiedtheorganicacidquantityandcompositionofthreecommonlyoccurringpioneerplantspecies,thelegumesLotuscorniculatusL.andTrifoliumarvenseL.andthegrassCalamagrostisepigeios(L.)Roth,todetermineifplantgrowthandexudationdifferedwith(non-sterilizedsoil)andwithout(sterilizedsoil)anindigenoussoilmicrobialcommunity.Weinvestigatedwhetherorganicacidswerefoundintherhizosphereandsurroundingsoilandwhetherthisinfluencednutrientmobilization.Thisstudyconsistsoflinkedfieldinvestigationsandagreenhouseexperiment.Plantsweregrowninthegreenhouseineithersterilizedornon-sterilizedsandysoilfromareclamationsiteintheLusatianmininglandscape(WelzowSu¨d,EastGermany).Aftersevenmonths,theplantbiomass,rootmorphology,organicacids,andwater-solublenutrientsandrootcolonizationwitharbuscularmycorrhizalfungi(AMF)anddarkseptateendophytes(DSE)wereanalyzed.RootsofallthreeplantsinthefieldandgreenhouseexperimentswerehighlycolonizedwithAMF.CalamagrostisepigeiosandT.arvensehadasignificantlyhighercolonizationfrequencywithDSEthanL.corniculatus.Thequantityandcompositionoforganicacidsstronglydifferedamongplantspecies,withthehighestnumberoforganicacidsfoundforL.corniculatusandlowestforC.epigeios.Thequantityoforganicacidswasgreatlyreducedinallplantsundersterilizedsoilconditions.However,thecompositionoforganicacidsandplantgrowthinsterilizedsoilwerereducedforbothlegumes,butnotforC.epigeios,whichhadahigherbiomassundersterilizedconditions.Changesinnutrientconcentrationsinthefieldrhizospheresoilrelativetothoseinthecontrolweremeasurableaftersevenmonths.Whilethespectrumoforganicacidsandthegrowthoflegumesseemedtobedependentonahighly