简介：TheimpactofpHchangesonmicrobialbiomasscarbon(Cmic)andmicrobialbiomassphosphorus(Pmic)wereexaminedfor3redsoilsundercitrusproductionwithdifferentlengthsofcultivation.SoilpHsignificantlyaffectedCmicandPmic.TheCmicandPmicchanges,asafunctionofsoilpH,appearedtofollowanormaldistributionwiththeoriginalsoilpHvalueattheapexandaspHincreasedordecreasedcomparedtotheoriginalsoilpH,CmicandPmicdeclined.Moreover,therewerecriticalpHvaluesatbothextremes(3.0ontheacidicsideand8.0to8.5onthealkalineside),beyondwhichmostofmicroorganismscouldneversurvive.TheeffectofpHonCmicandPmicwasalsorelatedtotheoriginalsoilpH.ThehighertheoriginalsoilpHwas,thelessCmicorPmicwereaffectedbypHchange.ItissuggestedthatsoilmicroorganismsthatgrowinasoilenvironmentwithamoreneutralsoilpHrange(I.e.pH5.5-7.5)mayhaveagreatertolerancetopHchangesthanthosegrowinginmoreacidicormorealkalinesoilpHconditions.

简介：Thisstudywasdesignedtounderstandtheimpactofmethylbromide(MB)(CH3Br)anditsalternativesonbothfree-livingandroot-knotnematodesinthesoil.Arandomizedcompleteblockexperimentwithsixtreatmentsand4replicates(eachreplicateinaseparategreenhouse)wasestablishedinQingzhou,ShandongProvince,China.InadditiontoMBanduntreatedcontrol(CK)treatmentstherewerefouralternativesoilfumigationpracticesincludingMB+virtuallyimpermeablefilms(VIF),metamsodium(MS),MS+VIFandsoilsolarizationcombinedwithselectedbiologicalcontrolagents(SS+BCA).Twotomato(LycopersicumesculentumMill.)cultivars,cv.Maofen-802fromtheXianInstituteofVegetableScience,China,andcv.AF179BrillantefromtheIsraeliHazeraQualitySeeds,wereselectedastestcrops.TheresultsindicatedthatRhabditidaewasthemostdominantpopulationwithpercentageabundanceashighas85%ofthetotalnumberofidentifiedfree-livingnematodes,followedbythatofCephalobidae.Methylbromideanditsalternativesexceptforthenon-chemicalSS+BCAtreatmentcontrolledthetargetpest,root-knotnematodes.Also,theimpactofthethreechemicalalternativesonfree-livingnematodenumberandfunctionalgroupabundancewassimilartotheimpactassociatedwithatypicalmethylbromideapplication.Chemicalfumigationpractices,especiallythatwithMB,significantlyreducedthenumberofnematodesinthesoilandsimultaneouslysignificantlyreducedthenumberofnematodegeneratherebyreducingnematodediversity.Allthefoursoilchemicalfumigationactivitiesdecreasedsoilmicrobialbiomassandhadanobviousinitialimpactonmicroorganismbiomass.Furthermore,bothplant-parasiticandfungivorenematodeswerepositivelycorrelatedwithsoilmicrobialbiomass.

简介：Theculturablebacterialpopulationandphospholipidfattyacid(PLFA)profileofcasingsoilwereinvestigatedatdifferentmushroom(Agaricusbisporus)croppingstages.ThechangeinsoilbacterialPLFAswasalwaysaccompaniedbyachangeinthesoilculturablebacterialpopulationinthefirstflush.ComparativelyhigherculturablebacterialpopulationandbacterialPLFAswerefoundinthecasingsoilattheprimordiaformationstageofthefirstflush.TherewasasignificantincreaseintheratiooffungaltobacterialPLFAsduringmushroomgrowth.MultivariateanalysisofPLFAdatademonstratedthatthemushroomcroppingstagecouldconsiderablyaffectthemicrobialcommunitystructureofthecasingsoil.Thebacterialpopulationincreasedsignificantlyfromcasingsoilapplicationtotheprimordiaformationstageofthefirstflush.Casingsoilapplicationresultedinanincreaseintheratioofgram-negativebacterialPLFAstogram-positivebacterialPLFAs,suggestingthatsomegram-negativebacteriamightplayanimportantroleinmushroomsporophoreinitiation.

简介：Alaboratoryincubationexperimentwasconductedtostudytheinfluenceofcadmium(Cd),lead(Pb)andzinc(Zn)onthesizeofthemicrobialbiomassinredsoil.Allthethreemetalswereapplied,separately,atfivedifferentlevelsthatwere:Cdat5,15,30,60,and100μgg^-1;Pbat100,200,300,450and600μgg^-1andZnat50,100,150,200and250μgg^-1soil,InComparisontouncaontaminatedsoil,themicrobialbiomasscarbonandbiomassnitrogendecreasedsharplyinsoilscontaminatedwithCd,PbandZn,AmoreconsiderableincreaseinthemicrobialbiomassC:Nratiowasobservedinthemetalcontaminatedsoilsthanthenon-treatedcontrol.Amongthetestedmetals,CddisplayedthegreatestbiocidaleffectfollowedbyZnandPb,showintheirrelativetoxicityintheorderofCd>Zn>Pb.

简介：PhyllostachyspraecoxC.D.ChuetC.S.Chao,afavoredbambooshootspecies,hasbeenwidelyplantedinrecentyears.Fourstandswithdifferenthistoricalmanagementpracticeswereselectedforthisstudytounderstandtheevolutionofsoilmicrobialecologybydeterminingtheeffectsofanewmulchingandheavyfertilizationpracticeonsoilqualityusingmicrobiologicalparameters.Comparedwiththetraditionalpractice(index1),microbialbiomasscarbon(MBC)andsoilmicrobialrespirationcarbon(MRC)withthenewmanagementpracticesignificantlydecreased(P＜0.01andP＜0.05,respectively)with1-2yearsofmulching(index2)andthenforcontinuedmulchingsignificantlyincreased(P＜0.05).TheratiosofMBC/TOC(totalorganiccarbon)andMRC/TOCalsosignificantlydiminished(P＜0.05)withmulching.Theaveragewellcolordevelopment(AWCD)andShannonindexdecreasedwithmulchingtime,andthesignificantdecrease(P＜0.05)inShannonindexoccurredfromindex2toindex3.Theresultsfromaprincipalcomponentsanalysis(PCA)showedthatthescoresofthefirstprincipalcomponentforindexes1and2weresignificantlylarger(P＜0.05)thansoilsmulched3-4yearsor5-6years.Also,thesecondprincipalcomponentscoresforindex1werelargerthanthoseforindex2,suggestingthattheabilityofsoilmicroorganismstoutilizesoilcarbonwasdecreasingwithlongeruseofthenewmanagementpracticeandcausingadeteriorationofsoilbiologicalproperties.

简介：Inordertoinvestigatetheeffectsofmicroorganismsandtheirureaseactivitiesinmacrophyticrootzonesonpollutantremoval,foursmall-scaleplots(SSPs)ofvertical/reverse-verticalflowwetlandsweresetuptodetermine:a)therelationshipbetweentheabundanceofmicroorganismsintherootzonesandwaterpurificationefficiency;andb)therelationshipbetweenureaseactivitiesintherootzonesandpollutantremovalinaconstructedwetlandsystem.Totalnumbersofthemicrobialpopulation(bacteria,fungi,andactinomyces)alongwithureaseactivitiesinthemacrophyticrootzonesweredetermined.Inaddition,therelationshipsbetweenmicrobialpopulationsandureaseactivitiesaswellasthewastewaterpurificationefficienciesoftotalphosphorus(TP),totalKjeldahlnitrogen(TKN),biochemicaloxygendemandin5days(BOD5),andchemicaloxygendemand(COD)werealsoanalyzed.Theresultsshowedthattherewasahighlysignificantpositivecorrelation(r=0.9772,P＜0.01)betweenthenumberofbacteriaintherootzonesandBOD5removalefficiencyandasignificantnegativecorrelation(r=-0.9092,P＜0.05)betweenthenumberoffungiandtheremovalefficiencyofTKN.Meanwhile,therewasasignificantpositivecorrelation(r--0.8830,P＜0.05)betweenureaseactivitiesintherootzonesandtheremovalefficiencyofTKN.Thus,duringwastewatertreatmentinaconstructedwetlandsystem,microorganismandureaseactivitiesintherootzoneswereveryimportantfactors.

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

简介：Nitrogen(N)applicationmayleadtonichesegregationofsoilammonia-oxidizingarchaea(AOA)andbacteria(AOB),therebyreducingthecompetitiveinteractionsbetweenAOAandAOBduetohigherammoniumsubstrateavailability.However,theadaptivemechanismsofAOAandAOBunderNenrichmentremainpoorlyunderstood.Stableisotopeprobing(SIP)microcosmincubationwasemployedtorevealcommunitychangesofactiveAOAandAOBinaloesssoilfromafieldexperimentgrowingpotatoesthatreceivednoN(control,CK),lowN(LN,75kgNha-1),andhighN(HN,375kgNha-1).Theresultsshowedthatthesoilpotentialnitrificationrate(PNR)wasmeasuredbyculturingofthesoilsamplesfromthefieldexperiment.SoilPNRwassignificantlyincreasedinHNby87.5%and67.5%comparedwithCKandLN,respectively.ComparedwithCK,the13C-amoAgenesofsoilAOAandAOBinHNhad2.58×104and1.55×106copies,representing1.6-and16.2-foldincreaserespectively.ItwasindicatedthatAOBdominatedsoilammoniaoxidation.Aphylogeneticanalysisofthe13C-amoAgeneshowedthatNapplicationsignificantlyincreasedtheproportionof54d9-likeAOAupto90%inHN,whiletheNitrososphaeragargensis-likeandNitrososphaeraviennensis-likeAOAwereinhibitedandcompletelydisappeared.NitrogenapplicationalsoresultedinthecommunityshiftofactiveAOB-dominantgroupfromNitrosospirabriensis-liketoNitrosospirasp.TCH711-like.OurstudyprovidescompellingevidencefortheemergenceandmaintenanceofactivenitrifyingcommunitiesundertheintensifiedNinputtoanagriculturalecosystem.

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：Thechangesofmicrobialbiomasscarbon(MBC)andnitrogen(MBN)andmicrobialcommunityinthetopsoiloftheabandonedagriculturallandonthesemi-aridLoessPlateauinChinaduringthenaturalsuccessionwereevaluatedtounderstandtherelationshipbetweenmicrobialcommunityandsoilproperties.MBCandMBNweremeasuredusingfumigationextraction,andmicrobialcommunitywasanalyzedbythemethodoffattyacidmethylester(FAME).ThecontentsoforganicC,totalN,MBC,MBN,totalFAME,fungalFAME,bacterialFAMEandGram-negativebacterialFAMEatthenaturalsuccessionsiteswerehigherthanthoseoftheagriculturalland,butlowerthanthoseofthenaturalvegetationsites.TheMBC,MBNandtotalFAMEwerecloselycorrelatedwithorganicCandtotalN.Furthermore,organicCandtotalNwerefoundtobepositivelycorrelatedwithfungalFAME,bacterialFAME,fungal/bacterialandGram-negativebacterialFAME.Naturalsuccessionwouldbeusefulforimprovingsoilmicrobialpropertiesandmightbeanimportantalternativeforsustainingsoilqualityonthesemi-aridLoessPlateauinChina.

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：Thechloroformfumigation-incubationmethowasusedtomeasurthesoilmicrobialbiomassC(SMBC)andN(SMBN)in16loessialsoilssampledfromAnsai,YongshouandYanglinginShaanxiProvince.TheSMBContentsinthesoilsrangedfrom75.9to301.0μgCg^-1withanaverageof206.μgCg^-1,accountingfor1.36%-6.24%ofthetotalsoilorganicCwithanaverageof3.07%,andtheSMBNcontentsfrom0.51to68.40μgNg^-1withanaverageof29.4μgNg^-1,accountingfor0.20%-5.65%ofthetotalNinthesoilswithanaverageof3.36%.AcloserelationshipwasfoundbetweenSMBCandSMBN,andtheybothwerepositivelycorrelatedwithtotalorganicC,totalN,NaOHhydrolizableNandmineralizableN.Theseresultsconfirmedthasoilmicrobialbiomasshadacomparativeroleinnutrientcyclesofsoils.

简介：土壤drying-rewetting(DRW)事件影响滋养的转变和微生物引起的社区作文；然而，很少对在DRW事件期间弄干紧张的影响被知道。因此，我们在一个试验性的drying-rewetting事件期间与暴露分析了土壤营养素作文和微生物引起的社区到各种各样的弄干的紧张，用从北中国的一块草地的淤泥沃土，在半干旱的气候暴露土壤到大量潮湿条件的地方，并且草地占超过40%国家陆地区域。我们也进行了一个消毒实验检验土壤微生物的贡献到滋养的脉搏。土壤drying-rewetting减少了由9%-27%的碳(C)矿化作用。monosaccharide和矿物质氮(N)内容与更高弄干紧张增加了(弄干到10%gravimetric水内容)，与最高的弄干紧张随增加是204%和110%(弄干到2%gravimetric水内容)，分别地而易变的磷(P)仅仅增加了(在105%)与最高的弄干紧张。而且，微生物引起的生物资源C和N和溶解器官的N的层次与增加弄干紧张减少了并且分别地，而易变的P的增加不与在微生物引起的生物资源P的减小一致，随溶解器官的C和矿物质N的增加被相关。消毒实验结果显示微生物为C和N脉搏主要负责，而非微生物引起的因素是到易变的P脉搏的主要贡献者。Phospholipid丰满的酸分析显示土壤微生物对drying-rewetting事件高度抵抗并且干旱抵抗的组为滋养的转变可能负责。因此，现在的学习证明在drying-rewetting事件期间弄干的中等土壤能改进N，然而并非P的矿化作用，并且不同机制为C，N，和P脉搏负责，这在drying-rewetting期间观察了事件。

简介：Soilmacroinvertebratesarehighlydiverseandtheirmajorecologicalserviceincludebreakdownoforganicmatterandinturnimprovesoilfertilityandpill-millipedesarewell-knownfortheirsigni?cantroleiningestion,disintegrationanddecompositionoforganicmatterinsoil.Thisstudycharacterizedthefeed,thedecomposingleaflitterofcoconut(Cocosnucifera),andfaecesoftwoendemicgiantpill-millipedesArthrosphaeradistictaandA.fumosacollectedfromforestsoftheWesternGhatsofIndiabasedonchemicalfeaturesandmicrobialpro?le.Inbothmillipedes,electricconductivityandtotalphosphorusweresigni?cantlyincreasedinfaeces,whilethecrudeprotein,organiccarbon,totalnitrogenandtotalphenolicsweresigni?cantlydecreased,ascomparedtothoseinfeed.Heterotrophicbacteria,actinomycetes,rhizobiaandphosphate-solubilizingbacteriaweresigni?cantlyhigherinfaecesthaninfeed,while?lamentousfungiandyeastsubstantiallydecreasedinfacescomparedtofeedinboththemillipedes.Spectrumoffattyacidmethylesterswasconsiderablydifferentbetweenfeedandfaecesofboththemillipedes.Thetotalsaturatedfattyacidswerehigherthanthetotalunsaturatedfattyacidsinfeedaswellasfaeces,whiletheratioofunsaturated/saturatedfattyacidsdecreasedfromfeedtofaeces.DodecanoicandtetradecanoicacidsinA.distictaandoctadecanoicacidinA.fumosasigni?cantlyincreased,while(9Z)-octadec-9-enoicand(9E,12E)-octadeca-9,12-dienoicacidsinA.distictaandhexadecanoic,tetracosanoicand(9E,12E)-octadeca-9,12-dienoicacidsinA.fumosasigni?cantlydecreasedinfaecescomparedtofeed,indicatingmillipede-dependentchangesinfattyacids.Icosanoicacidwaspresentinfaecesofboththemillipedes,andhexadec-9-enoicacidwascon?nedtofaecesofA.disticta,whilepentadecanoic,heneicosanoic,(9Z,12Z,15Z)-9,12,15-octadecatrienoicandeicosenoicacidswerecon?nedtofaecesofA.fumosa.Pill-millipedesenrichthesoilqualitybyleaflitterconditioningintheirgutthroughspeci?cmi

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.