简介：Phosphorus(P)isalimitedresourcethatcouldbedepleted.Consequently,recyclingthePcontainedinsewagesludge,includingsewagesludgeincinerationash(SIA),fromwastewatertreatmentplantsisapossibilitytobeexplored.Agreenhouseexperimentusingannualryegrass(LoliummultiflorumL.)wasperformedwithanexperimentaldesignofthreecompletelyrandomizedblocksoftwosoilsand29treatments:onecontrolwithoutPandtwolevelsof9and26kgtotalPha-1from14differentsources:twelveSIAs(notcontaminatedbytracemetals)fromtheUSandCanada,onecommercialsyntheticfertilizer(triplesuperphosphate(TSP)),andonecommercialrockphosphate(RP).Higherryegrassbiomasslevelswereachievedatthehigherfertilizationrate(26kgtotalPha-1)andwhenusingtheSIAswiththehighestPsolubilitypercentage(PSP)(≥54%oftotalP).ThebiomassincreasesfollowingSIAapplicationwereashighas29%and59%morethanthecontrolforthesandyloamandclayeysoil,respectively,but40%lessthaninTSPforbothsoils.AsimilarbehaviorwasobservedforPuptake,withamaximumincreaseof26%fortheclayeysoil,and165%forthesandyloamsoil.TheryegrassbiomassandPuptakeincreasesduetoSIAapplicationwerelargerthanthoseduetoRPapplicationintheclayeysoil,butsimilartothoseinthesandyloamsoil.TheSIAswithaPSPof≥54%significantlyincreasedsoilavailablePstocksandsaturation.Accordingtoourfindings,weconcludethattheSIAsfrommunicipalandagrifoodindustrieshaveapotentialforPagriculturalrecycling,buttheirefficienciesvary.

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：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：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：Anaerobicdigestionisaprocessthatiswidelyusedforthetreatmentoforganicwastes.Thedigestatecanbeusedasasoilamendmentorcropfertiliser.Theaimsofourworkweretoevaluate1)thephysicochemicalcompositionandpathogencontentinadigestatefrompoultrymanure,accordingtointernationalregulations,and2)theeffectofitssoilapplicationonthemajorchemicalandbiologicalsoilpropertiesandonthegrowthofLactucasativa.Theexperimentconsistedoftwogroupsofpots(withandwithoutcrop).Treatmentsappliedtoeachgroupwereasfollows:lowandhighdosesofdigestateandinorganicfertiliser,andnoapplication(control)(lowdose:70kgnitrogen(N)ha-1and21kgphosphorus(P)ha-1;highdose:210kgNha-1and63kgPha-1).Soilsamplesweretaken7and34d(harvest)aftertreatmentapplications.Heavymetalandpathogencontentsinthedigestatewerebelowtheupperlimitvalues.DespitethehighpHandelectricalconductivityvaluesofthedigestate,bothsoilparameterspresentedacceptablevaluesforcropgrowth.AlthoughtherewerenoinitialincreasesintotalinorganicNandavailablePinsoilwithdigestateapplication,anincreaseinthefreshweightofcropwasobservedwiththehighdoseapplication.Thisisprobablyassociatedwiththeslownutrientreleasefromthedigestateduringthedevelopmentofthecrop.Changesinthemicrobialcommunityweretemporaryandoccurredattheinitialsamplingstageoftheexperiment.

简介：Background:Theeffectofforestfireonsoiliscomplexandrelativelylessunderstoodthanitsabovegroundeffect.Understandingtheeffectoffireonforestsoilscanallowimprovingmanagementofvaluableforestecosystemsasadequateandproperinformationisveryimportantforefficientmanagement.Wehavestudiedtherecoveryofsoilpropertiesafterfire,usingachronosequenceapproach(two,fiveandfifteenyearsafterfireandcontrol).Soilsampleswerecollectedfromeachplotoffourfirepatches(B0,B2,B5&B15)fromthreedifferentdepthsviz.0–10(Top),10–20(Middle),and20–30cm(Bottom).Results:Soilorganiccarbonwaslowerthanunburnedplotsafterthefireandcouldnotrecovertothelevelofunburnedplot(B0)evenin15years.TotalN,availableP,andextractableKwerelower2-yearsand5-yearsafterthefirebutarehigherthanunburnedplotafter15-years.Availablenitrogen(NO3^-andNH4^+)remainunchangedorhigherthanB0inburnedpatches.SoilpH,BulkDensity,WaterHoldingCapacity,andElectricalConductivitywaslowerinitiallyafterthefire.Forestfireshaveaffectedsoilpropertiesconsiderably.Theresponseofsoilpropertiesvariedwithyearsafterfireandsoildepth.Conclusion:Forestfiresoccurveryfrequentlyinthestudyarea.Significantquantitiesofcarbonandtotalnitrogenarelosttotheatmospherebyburningoflitter,duff,andsoilOM.Becausenitrogenisoneofthemostimportantsoilnutrients,therecaptureofNlostbyvolatilizationduringafiremustreceivespecialattention.Long-termstudiesarerequiredtobetterunderstandtherecoveryofsoilnitrogen.

简介：Organicamendmentssuchasvermicompostandbiocharhavebeenreportedtoenhancesoilfertilityandcropproductivity.However,whethertheco-applicationofbothamendmentshassynergisticeffectsorwhethersuchbenefitsareaccompaniedbytheriskofgaseousnitrogen(N)lossinanagroecosystemremainsunknown.Asoilcolumnexperimentwithafullyfactorialdesignwasconductedusingthreelevelsofvermicompost(nodose,lowdose(1%,weight:weight),andhighdose(3%,weight:weight))withoutorwithbiochar(1%,weight:weight)toinvestigatetheireffectsonricegrowthandgaseousNlossacrossthecropgrowingseason.Ourresultsdemonstratedthatsynergisticinteractionsexistedbetweenvermicompostandbiocharinpromotingcropyield.Comparedwithbiocharamendmentalone,biocharcombinedwithvermicompostsignificantly(P<0.01)increasedriceyieldby26.5%–35.3%.However,highdoseofvermicompostsignificantly(P<0.01)increasedthecumulativeammonia(NH3)andnitrousoxide(N2O)emissions.Inthepresenceofvermicompost,theincorporationofbiocharamendmentsignificantly(P<0.01)decreasedthecumulativeN2Oemissionby14.1%–18.6%.ThelowestemissionfactorvalueofNH3andN2Owasachievedusingbiocharincombinationwithlowdoseofvermicompost.Thisstudyrevealedthatthecombinationofbiocharandmoderatedoseofvermicompostoffersanovelapproachtopromotecropproductivitywhilereducingtheenvironmentalrisk.