简介：因为快速的都市化和工业化，在仙子城市的区域的蔬菜地在中国收到大量体外的重金属。在30的Cu，Zn，和Pb的集中玷污样品和32件蔬菜样品，在中国的南部的江苏省从30个不同地点收集了，被测量，他们到蔬菜的从土壤的转移被决定。结果证明土壤样品有pH的宽范围(4.257.85)并且电的电导率(EC)(0.243.42dSm?1)。在土壤样品之中，有四件土壤样品和比那些在中国土壤指定环境优秀标准II包含更高的Zn集中的二件土壤样品，包含更高的Cu。然而，没有蔬菜样品被发现包含Cu或Zn的高水平。相反，一件蔬菜样品包含了0.243mgPbkg?1FW，在中国食物卫生标准上面，而相应土壤Pb集中比汉语低，玷污环境优秀标准II。所有蔬菜样品的Cu的转移系数超过了建议系数范围，暗示体外的Cu有到蔬菜的高活动性和简历可获得性。在可引出的土壤之间没有重要关联有四种提炼之物和土壤pH的重金属集中，EC，在蔬菜和土壤的重金属集中除了土壤pH与1.0摩尔L与可引出的土壤Cu，Zn，和Pb集中相关很好之外?1NH4NO3。而且，diethylenetriaminepentaacetic酸(DTPA)抽取方法比另外的三个方法使用是从土壤pH和EC的土壤独立人士提取重金属的一个更有效的方法。

简介：Anincubationexperimentwasconductedtosimulatetheeffectoffloodingonwaterdeoxygenationinacidsulfatesoilfloodplainsystems.Theoriginallyoxygenated'floodwater'couldbedeoxygenatedimmediatelyfollowing'flooding'anditislikelythatthiswascausedmainlybydecompositionoforganicdebrisfromtheinundatedplants.Deoxygenationeventuallyledtothedepletionofdissolvedoxygen(DO)inthe'floodwater'anditishighlypossiblethatthisresultedinthetransformationsofferricFetoferrousFe,sulfatetohydrogensulfide,andorganicnitrogentoammonia(ammonification).Theaccumulationofthesereducedsubstancesallowsthe'floodwater'todevelopDO-consumingcapacity(DOCC).Whenthe'floodwater'ismixedwiththeintroducedoxygenatedwater,apartfromthedilutioneffects,thereducedsubstancescontainedinthe'floodwater'oxidizetofurtherconsumeDOcarriedbytheintroducedwater.However,itappearsthattheDOdropinthemixedwatercanonlylastforafewhoursifnoadditionalDO-depleted'floodwater'isadded.EntryofatmosphericoxygenintothewatercanraisetheDOlevelofthemixedwaterandlowerwaterpHthroughtheoxidationofthereducedsubstances.

简介：Fourtestingmethodsusingcationexchangemembrane(CEM),ammoniumacetate,ASI(0.25molL^-1NaHCO3+0.01molL^-1EDTA+0.01molL^-1NH4F)and1.0molL^-1boilingnitricacid,respectively,wereusedtoevaluatesoilavailableK.ThesoilKtestedbyCEMwassignificantlycorrelatedwiththatbytheother(conventional)methods(r^2=0.43^**-0.95^***).ThesoilKtestedbyCEMsaturatedwithNH4HCO3(15minextraction)wasmostcloselycorrelatedwiththatbytheothermethods(r^2=0.60^**-0.95^***),Potassiumavailability,aspredictedbysoiltest,wascomparabletoactualKuptakebycanolaandwheatgrownonthesoilsingrowthchamber.RegressionanalysesshowedthatplantKuptakewasmorecloselycorrelatedwihtKextractedbyCEM(r^2=0.56^**-0.81^***)thanthatbytheconventionalmethods(r^2=0.46^***-0.81^***),mostcolselycorrelatedwiththatbyNH4HCO3-saturatedCEMfor15min(r^2=0.81^***).andworstcorrelatedwiththatbyHNO3(r^2=0.45^**-0.72^***)

简介：Researchsamplesweretakenfromanancientgravelstratumwhichisnotonlyarepresentativesoillayeralongthemiddle-lowerreachesoftheYangtzeRiverinEastChina,butalsooneoftheprimaryNeozoicstratainNanjingdistrict.Locatedmostlyonthesecondandthirdterraces,theancientgravelstrataformedthegeomorphiclandscapesofterraceandstep.Theywerecomplexinconstitution,variedwidelyinstability,ofmultiplesources,locallyderived,andassociatedwithbraidedstreamsinthedepositionenvironment.ACIPW(Cross,Iddings,PirssonandWashington)methodmodifiedbytheauthorwasusedtoanalyzethesoi-rock-formingmaterialsoffinergrains(lessthan2mminsize)oftheancientgravelstratum.Resultsoftheanalysisshowedthatthesandygrainswerecomposedofapatite,ilmenite,potassiumfeldspar,plagioclase,enstatiteandfreequartz,theclaymainlyofkaolinite,andthecementofacombinationofsilicon,aluminumandironataratioof46:44:10.Inthesoil-rock-formingprocesses,includingcompactionalsolidification,water-stableilluviation-cementation,homogeneousovergrowthandsoon,theloosesoil-rock-formingcomponentsgraduallychangedintoconsolidatedsoilandfurthertotheearlystageoflithification.Meanwhile,fromtheanalysis,wefoundthattheancientgravelstratumhadbeenprotectedbytheoverlyingXiashuloessorbasaltandtheoverloadingresultedinoverconsolidatedstrata.ThemodifiedCIPWmethodwasapplicableandeffectiveforsemi-quantitativeanalysis.

简介：ThroughapotculturelanthanumnitratewasappliedtomaizeseedlingsgrowninaredloamysoiltoinvestigatethephysiologicalandtoxiceffectsofaddedLaonthegrowthofcropseedlingsandLabioaccumulationtohelpunderstandtheenvironmentalchemistrybehaviorsofrareearthelementasfertilizersinsoils.Comparedtothecontrol,LaconcentrationsinshootsandespeciallyinrootsofmaizeseedlingsincreasedwithanincreaseofLainthesoil.Also,withaddedconcentrationsofLa≥0.75gLakg-1soiland≥0.05gLakg-1soil,thedryweightofshootsandrootsofmaizeseedlingswassignificantlyreduced(P≤0.05),respectively,comparedwiththecontrol.Additionally,La≥0.5gkg-1inthesoilsignificantlyinhibited(P≤0.05)primaryrootelongation.RootsweremoresensitivetoLastressthanshootsandthuscouldbeusedasabiomarkertoLastress.Overall,intheredloamysoilstudied,LahadnosignificantbeneficialeffectsonthegrowthofmaizeattheaddedLalevelsabove0.1gkg-1soil.

简介：Thisstudyinvestigatestheeffectsofincreasingsoilpenetrationresistance(SPR)onseedlingmorphologyandseedlingarchitecture.WhenseedlingsofdeciduousCappadocianmaple(AcercappadocicumGled.)weregrowninagreenhouseinaloamysoilunderawiderangeofsoilcompactions,allmorphologicalvariablesstudiedchangedsignificantlywithincreasingSPR.TherelationshipsbetweenincreasingSPRandallmorphologicalresponsesexceptlateralrootlengthfollowedanegativequadraticcurve.Allbiomassvariablesexceptlateralrootbiomassshowedabell-shapedresponsewithrespecttoSPR,withamaximumbiomassvariablebetween0.6and1.2MPa,decreasingathighersoilcompactionvalues.Allallocationratiosweresignificantlyaffectedbysoilpenetrationresistance.Biomassallocationtorootswasalsoaffectedbysoilcompaction.Therewasnotasignificantrelationshipbetweenthespecificstemlengthandincreasingsoilpenetrationresistance.ThespecificrootlengthshowedtwotrendstoincreasingSPR;itfirstdecreasedinresponsetothemoderatecompactiontreatment(uptoabout1.2MPa),thenincreasedsignificantly.WeconcludedthatincreasingsoilcompactioncausedmorphologicalchangestorootandshootsectionsofA.cappadocicumseedlings.

简介：AleachingexperimentwasCarriedoutwithrepackedsoilcolumnsinlaboratorytostudytheleachingprocessofaredsoilderivedfromsandstoneasaffectedbyvariousfertilizationpractices.ThetreatmentswereCK(asacontrol),CaCO3,CaSO4,MgCO3,Ca(H2PO4)2,Urea,KCl,Multiple(amixtureoftheabovementionedfertilizers)andKNO3,Thefertilizerswereaddedtothebaresurfaceofthesoilcolumns,andthenthecolumnswereleachedwith120mLdeionizedwaterdailythroughperstalticpumpsoveraperiodof92days,Attheendofleachingprocess,soilsweresampledfromdifferentdepthsofthesoilprofiles,i.o.,of92days,Attheendofleachingprocess,soilsweresampledfromdifferentdepthsofthesoilprofiles,I.e.0-5cm,5-10cm,10-20cm,20-40cm,and40-60cm,TheresultsshowedwhenapplyingCa,Mg,andKtothebaresurfaceofthesoilcolumns,exchangeableCa^2+,Mg^2+,andK^+intheupperlayerofthesoilprofileincreasedcorrespondingly,withanextentdependingmainlyontheapplicationratesofCa,Mg,andKandshowingadownwardtrend,CaCO3,CaSO4,MgCO3,andCa(H2PO4)2treatmentshadscarcelyandeffectonmovementofexchangeableK^+,whileCaCO3,andCaSO4treatmentssingnificantlypromotedthedownwardmovementofexchangealbleMg^2+althoughthesetwotreatmentshadnoobviouseffectonleachinglossesofMg,ThefactthatunderUreatreatment,exchangeableCa^2+andMg^2+,werehigherascomparedtoCKtreatmentshowedureacouldpreventleachingofexchangeableCa^2+andMg^2+,theobviousdownwardmovementofexchangeableCa^2+andMg^2+wasnoticedinKCltreatment,InMultipletreatment,thedownwardmovementofexchangeableCa^2+andMg^2+wasevident,whilethatofK^+waslessevident,ApplicationofKNO3stronglypromotedthedownwardmovementofexchangeableCa^2+andMg^2+inthesoilprofile.

简介：Background:WecomparetheclimatesensitivityofEuropeanbeech(FagussylvaticaL)intwoforestnaturereservesinnortheasternGermany.Theonereserve,Schlossberg,ischaracterizedbyshallowchalksoils,whereasintheotherreserve,Eldena,soilsaredeeperandmoredeveloped.Littleisknownaboutthedroughtsensitivityofbeechonshallowchalksoils.Methods:Wecollectedincrementcoresatbothresearchsitesandestablishedclimate-growthrelationships.Intertreevariabilitywasassessedbyemployinglinearmixed-effectmodels.Results:WeexpectedtofinddistinctivelyhigherdroughtsensitivityatSchlossbergduetolimitedwateravailability,butfindonlymarginaldifferencesingrowthresponses.Atbothsites,droughtisthemajorclimaticfactordrivingtreegrowth.Adaptationsintreearchitectureandanunderestimationofthewaterholdingcapacityofshallowchalksoilsarediscussedaspossiblereasonsfornotfindingmoredistinctclimateresponses.Inanalyzingclimate-growthrelationships,wespecificallyfocusedongrowthresponsesofindividualtreesbutobservedonlylowinter-treevariabilityatbothsites.Evidentisashiftinclimateresponsepatternsfromthefirsttothesecondhalfofthetwentiethcenturywithprevious-yeardroughtconditionsbecomingmoreimportantthancurrent-yeardrought.Thisshiftisdiscussedinrelationtoawarmingtrendoverthatsameperiod,aswellaspossibletrendsinmastingbehaviorofbeech.Conclusion:Theinvestigatedbeechtreesontheshallowchalksoilareonlyslightlymoredroughtsensitivethanbeechtreesonthereferencesitewithdeeperandmoredevelopedsoils.

简介：

简介：TheintegratedeffectofirrigationandagriculturalpracticesonsoilsalinityintheJordanValley(JV),whereover60%ofJordan'sagriculturalproduceisgrown,wasinvestigatedinthisstudyduring2009-2010.Duetothedifferencesinagriculturaloperations,croppingpatterns,irrigationmanagement,andweatherconditions,206top-andsub-soilsamplesweretakenevery1to3kmfromrepresentativefarmsalonganorth-south(N-S)transectwith1to2kmlateralextents.Soilelectricalconductivityofsaturatedextract(EC_(se)),Ca,Mg,K,Na,Cl,andNaadsorptionratio(SAR)weredeterminedinsaturatedpasteextracts.Resultsindicatedthatabout63%ofsoilsintheJVareindeedsaline,outofwhichalmost46%aremoderatelytostronglysaline.AlongtheN-StransectoftheJV,EC_(se)increasedfrom4.5to14.1dSm~(-1)intop-soilsamples.Similarincreasewasobservedforthesub-soilsamples.Themajorchemicalcomponentsofsoilsalinity;i.e.,Ca,Mg,andCl,alsoshowedasimilarincreasealongtheN-Stransectofthevalley.Moreover,comparedtopreviousfieldsampling,resultsshowedthatchangesinsoilsalinityintheJVweredramatic.Inaddition,itwasfoundthatClimposedanexistingandpotentialthreattosensitivecropsin60%ofthesoilsintheJV,whereClconcentrationsweregreaterthan710mgL~(-1).UndertheprevalentaridMediterraneanconditions,improvingthemanagementofirrigationwater,crops,andnutrientinputsandincreasingwaterandfertilizeruseefficienciesshouldbeindispensabletoconserveandsustainthealreadyfragileagriculturalsoilsintheJV.

简介：InsouthernChina,collapsinggullyerosionproducesmassivedepositsofsedimentontheploughlayerofalluvialfanfarmland,leadingtoreducednutrients,increasederodibility,andevendesertification.Theaimofthisstudywastoinvestigatesoilerodibility(thefactorKintheUniversalSoilLossEquation,USLE)andphysicochemicalpropertiesofthealluvialfansofthemostseverecollapsinggullyerosionareas(Hubei,Jiangxi,Fujian,andGuangdongprovinces)insouthernChina.Thesoilsofthecollapsinggullyalluvialfanshadahigherbulkdensity,butalowertotalporosity,saturatedwatercontent,andsiltandclayfractionsthanthecontrol(CK)soilsfromthefarmlandwithoutdesertification.Soilqualitygraduallydecreasedfromfanedgetofanhead.SignificantdecreaseswerefoundinsoilpH,organicmatter,cationexchangecapacity,andtotalpotassium,nitrogen,andphosphorus,aswellasavailablenitrogen,phosphorus,andpotassium,resultinginagradualdecreaseinsoilnutrientsfromthefanedgetothefanhead.Soilerodibilitywasgreatestinthefanhead,andsoilerodibilityKvaluesofthealluvialfanswere53.71%,66.28%,67.53%,and71.68%greaterthanthatinthoseoftheCKsoilsofHubei,Jiangxi,Fujian,andGuangdong,respectively,indicatingasignificantcorrelationbetweenthesoilerodibilityKvaluesandphysicochemicalproperties,particularlysandfractionandorganicmattercontent.Theresultsprovidenewinsightsintotherelationshipbetweensoilphysicochemicalpropertiesanderodibilityofalluvialfans,andsuggestthatimprovingsoilstructuremightincreasesoilfertilityinthecollapsinggullyalluvialfanfarmland.

简介：Theeffectsofsimulatedacidrainretainedinsoilonthepropertiesofacidsoilanditsdiminishingbyapplicationofgroundphosphaterockwereinvestigatedbyusingthesorptionmethod.Resultsshowasfollows:(1)Foryellowbrownsoil,theeffectofsimulatedacidrainonthepropertiesofsoilwithapHvalueof5.9wasrelativelysmall,exceptagreatquantityofacidraindepositedonit.(2)forredsoil,theeffectofsimulatedacidrainonthepropertiesofsoilwassignificant.Withtheincreaseoftheamountofaciddeposition,thepHvalueofsoilwasdeclined,butthecontentsofexchangeableH^+,Al^3+andMn^2+andtheamountofSO4^1-retentionwereincreased.(3)Manypropertiesofacidsoilscouldbeimprovedbyapplyinggroundphosphaterock.Forexample,pHvalueofsoilsandtheamountsofavailablePandexchangeableCa^2+andMg^2+wereincreased,andtheamountsofexchangeableH^+andAl^3+andSO4^2-retainedwasreduced.Theapplicationofgroundposphaterockcouldeffctivelydiminishthepollutionofacidraintosoil.

简介：InordertostudytheinfluenceofdifferenceinC2H2concentrationontheproductionofCO2,N2O,NH4-Nandvolatilefattyacids(VFA).soilslurrieswithagradientinC2H2concentrationwereanaerobicallyincubatedat25℃for2weeks.Acetate,butyrateandCO2productionandNH4-NaccumulationwereinhibitedintheslurresinthepresenceofC2H2;andtheinhibitioneffectincreasedwithincreasingC2H2from0to20kPaintheheadspacegasoftheincubationbottle.However,N2O,isobutyrateandpropionateproductionwasnotobviouslydifferentamongtheslurresamendedwithC2H2from2.5to20kPa.Therefore,theresultsimpliedthattheC2H2didnotpromotetheinhibitionbutonlyincreasedthesideeffectonothermicrobialprocesses.TheC2H2of2.5kPawassuggestedtobetheoptimumchoiceforthepresentdenitrificationstudy.

简介：Weconductedastudytofindoutifarbuscularmycorrhizal(AM)fungi(Acaulosporascrobiculata,Scutellosporacalospora)andphosphatesolubilizingbacteria(PSB,Paenibacilluspolymyxa)inoculationeitherindividuallyorincombinationscanimproveAcaciaauriculiformisseedlinggrowth,uptakeofnutrientsandqualityinaphosphorusdeficienttropicalAlfisol.Theseedlingswereassessedforvariousgrowthandnutrientuptakeparametersafter60daysoftreatment.InoculationwithP.polymyxastimulatedmycorrhizalformation.Seedlingheight,stemgirth,taprootlength,numberofleavesandleafarea,plantdrymatterproduction,nodulation,andnodulardryweightweresignificantlyhigherforseedlingsthatwereeitherdualinoculatedortripleinoculatedcomparedtoindividualinoculationofAMfungiorPSB,anduninoculatedseedlings.DualandtripleapplicationofAMfungiandPSBalsosignificantlyimprovedthenutrientcontentsofshootsandrootsandnutrientuptakeefficiencies.ThecalculatedseedlingqualityindexesoftheAMfungiandPSBinoculatedseedlingwere25–208%higherthanuninoculatedseedlings.ThesefindingsshowthatA.auriculiformisseedlingswhendualinoculatedortripleinoculatedperformedbetterthanseedlingsinoculatedwiththemicrobesindividuallyandcomparedwithuninoculatedcontrolseedlings.Weconcludethatbioinoculationisimportantfortheproductionofhigh-qualityA.auriculiformisseedlingsintreenurseriesforplantinginnutrientdeficientsoils.

简介：ThenitrogendepositionexperimentsonCinnamomumcamphoraplantationofHunanprovincialbotanicalgardenweresimulatedfromJunethe7thtoOctoberthe7th,2010,thenitrogendepositionlevelswasrespectivelyascontrol(CK,0g·m-2a-1),lownitrogen(LN,5g·m-2a-1),mediumnitrogen(MN,15g·m-2a-1)andhighnitrogen(HN,30g·m-2a-1).ThesoilrespirationspeedandsoilsurfacetemperatureandthesurfacewatercontentofthesoilweredeterminedbyLI-8100measuringinstrument.TheresultsshowthattheaveragevaluesofsoilrespirationspeedwereCK(4.09±0.66μmol·m-2s-1),LN(2.39±029μmol·m-2s-1),MN(2.18±0.19μmol·m-2s-1),HN(2.28±0.25μmol·m-2s-1),andthetreatmentoftheCKwasobviouslyhigherthantheotherthreetreatments（P<0.01）.Withdifferentnitrogenconcentrationsdepositiontreatments,theQ10（temperaturesensitivitycoefficients）forsoilrespirationofCK,LN,MNandHNtreatmentswere1.84,1.71,1.83and1.56.Itwaspositivecorrelationbetweentherespirationspeedandthesurface（≤10cm）temperatureoftestedsoil.Itwasnegativecorrelationbetweentherespirationspeedandthesurface（≤5cm）watercontentoftestedsoil（P>0.05）.Volumetricwatercontentof5-cmsoilwasbetween0.2666-0.2944(m3·m-3),andthemonthlycontentdidnotvarytoomuchduringtheresearchperiod（1.8%-9.4%）.ThefindingssuggestthattheinitialstageofnitrogendepositionobviouslyinfluencedthesoilrespirationofC.camphoraplantation.

简介：ThispaperanalyzestheimpactsofphysicalbackgroundandhumanactivitiesonsecondarysoilsalinizationinaridHetaoPlain,overviewstheadoptedameliorationstrategies,andsuggeststhecorrespondingstrategiesdealingwithwatershortageintheYellowRiver.

简介：Background:Soilorganiccarbon(SOC)isalargereservoirofterrestrialcarbon(C);itconsistsofdifferentfractionsofvaryingcomplexityandstability.PartitioningSOCintodifferentpoolsofdecomposabilityhelpbetterpredictthetrendofchangesinSOCdynamicsunderclimatechange.InformationonhowphysicalfractionsandchemicalstructuresofSOCarerelatedtoclimateandvegetationtypesisessentialforspatialmodelingofSOCprocessesandresponsestoglobalchangefactors.Method:Soilsampleswerecolectedfrommultiplerepresentativeforestsitesofthreecontrastingclimaticzones(i.e.cooltemperate,warmtemperate,andsubtropical)ineasternChina.MeasurementsweremadeonSOCcontentsandphysicalfractionsofthe0–20cmsoillayer,andthechemicalcompositionofSOCofthe0–5cmsoillayer,alongwithmeasurementsandcompilationofthebasicsiteandforeststandvariables.Thelong-termeffectsoftemperature,litterinputs,soilcharacteristicsandvegetationtypeontheSOCcontentsandfactionswereexaminedbymeansof"spacefortimesubstitution"approachandstatisticalanalysis.Result:Meanannualtemperature(MAT)variedfrom2.1℃atthecooltemperatesitesto20.8℃atthesubtropicalsites.TotalSOCofthe0–20cmsoillayerdecreasedwithincreasingMAT,rangingfrom89.2g·kg^-1incooltemperateforeststo57.7g·kg^-1insubtropicalforests,atanaveragerateof1.87%reductioninSOCwitha1℃increaseinMAT.WithincreasingMAT,theproportionsofaromaticCandphenolicCdisplayedatendencyofdecreases,whereastheproportionofalkylCandA/O-Avalue(theratioofalkylCtothesumofO-alkylCandacetalC)displayedatendencyofincreases.Overall,therewerenosignificantchangeswithMATandforesttypeineitherthephysicalfractionsorthechemicalcomposition.BasedontherelationshipbetweentheSOCcontentandMAT,weestimatethatSOCinthetop20soillayerofforestspotentiallycontribute6.58–26.3PgCgloballytotheat

简介：Availablewaterandfertilizerhavebeenthemainlimitingfactorsforyieldsofspringwheat,whichoccupiesalargeareaoftheblacksoilzoneinnortheastChina;thus,theneedtosetupappropriatemodelsforscenarioanalysisofcroppingsystemmodelshasbeenincreasing.ThecapabilityofCropSyst,acroppingsystemsimulationmodel,tosimulatespringwheatgrowthofawidelygrownspringcultivar,'Longmai19',intheblacksoilzoneinnortheastChinaunderdifferentwaterandnitrogenregimeswasevaluated.Fielddatacollectedfromarotationexperimentofthreegrowingseasons(1992-1994)wereusedtocalibrateandvalidatethemodel.Themodelwasrunfor3yearsbyprovidinginitialconditionsatthebeginningoftherotationwithoutreinitializingthemodelinlateryearsintherotationsequence.CropinputparametersweresetbasedonmeasureddataortakenfromCropSystmanual.Afewcultivar-specificparameterswereadjustedwithinareasonablerangeoffluctuation.TheresultsdemonstratedtherobustnessofCropSystforsimulatingevapotranspiration,abovegroundbiomass,andgrainyieldof'Longmai19'springwheatwiththerootmeansquareerrorsbeing7%,13%and13%oftheobservedmeansforevapotranspiration(ET),grainyieldandabovegroundbiomass,respectively.AlthoughCropSystwasabletosimulatespringproductionreasonablywell,furtherevaluationandimprovementofthemodelwithamoredetailedfielddatabasewasdesirableforagriculturalsystemsinnortheastChina.

简介：Thedynamicsofrhizospheremicrobialcommunitiesisimportantforplanthealthandproductivity,andcanbeinfluencedbysoiltype,plantspeciesorgenotype,andplantgrowthstage.ApotexperimentwascarriedouttoexaminethedynamicsofmicrobialcommunitiesintherhizosphereoftwosoybeangenotypesgrowninablacksoilinNortheastChinawithalonghistoryofsoybeancultivation.Thetwosoybeangenotypes,Beifeng11andHai9731,differinginproductivityweregrowninamixtureofblacksoilandsiliceoussand.Thebacterialcommunitieswerecomparedatthreezonelocationsincludingrhizoplane,rhizosphere,andbulksoilatthethirdnode(V3),earlyflowering(R1),andearlypod(R3)stagesusingpolymerasechainreaction-denaturinggradientgelelectrophoresis(PCR-DGGE)of16SrDNA.Theresultsofprincipalcomponentanalyses(PCA)showedthatthebacterialcommunitystructurechangedwithgrowthstage.Spatially,thebacterialcommunitiesintherhizoplaneandrhizosphereweresignificantlydifferentfromthoseinthebulksoil.Nevertheless,thebacterialcommunitiesintherhizoplaneweredistinctfromthoseintherhizosphereattheV3stage,whilenoobviousdifferenceswerefoundattheR1andR3stages.Forthetwogenotypes,thebacterialcommunitystructurewassimilarattheV3stage,butdifferedattheR1andR3stages.Inotherwords,somebacterialpopulationsbecamedominantandsomeothersrecessiveatthetwolaterstages,whichcontributedtothevariationofthebacterialcommunitybetweenthetwogenotypes.Theseresultssuggestthatsoybeanplantscanmodifytherhizospherebacterialcommunitiesintheblacksoil,andthereexistedgenotype-specificbacterialpopulationsintherhizosphere,whichmayberelatedtosoybeanproductivity.

简介：Potexperimentswereconductedin2002and2003toinvestigatetheeffectsofsoilcopper(Cu)concentrationongrowth,developmentandyieldformationofricebyusingthejaponicacultivarWuxiangjing14andhybridricecombinationShanyou63.Theplantheight,leafnumber,elongatedinternodenumberandheadingdateofriceplantswerenotaffectedatsoilCulevelsbelow200mg/kg,butaffectedsignificantlyatabove400mg/kg.TheinhibitoryeffectsonricegrowthanddevelopmentwereincreasedwiththeincrementofsoilCulevels.ThegrainyieldsdecreasedsignificantlywithraisingsoilCulevels.ThemainreasonsforthegrainyieldreductionsunderlowersoilCulevels(100,200mg/kg)weremainlyduetothedecreaseofnumberofspikeletsperpanicle,however,underhighersoilCulevels(morethan400mg/kg),bothpaniclenumberandnumberofspikeletsperpaniclecontributedtotheyieldloss.ThedecreasesofpaniclenumberbyCustressweremainlyattributedtoslowrecoveryfromtransplanting,delayedtilleringandreducedmaximumtillernumbers.ThereductionofnumberofspikeletsperpanicleundersoilGustressresultedfromthedecreasesofbothshootdryweight(SDW)attheheadingdateandtheratioofspikeletstoSDW.TotalbiomassatmaturitydecreasedsignificantlywiththeincreaseofsoilCulevels,whileeconomiccoefficientshowednon-significantdecreaseexceptundersoilCulevelsabove800mg/kg.