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：Theeffectsofsimulatednitrogen(N)depositiononsoilexchangeablecationswerestudiedinthreeforesttypesofsubtropicalChina.FourNtreatmentswiththreereplicationsweredesignedforthemonsoonevergreenbroadleafforest(matureforest):control(0kgNha-1year-1),lowN(50kgNha-1year-1),mediumN(100kgNha-1year-1)andhighN(150kgNha-1year-1),andonlythreetreatments(i.e.,control,lowN,mediumN)wereestablishedforthepineandmixedforests.Nitrogenhadbeenappliedcontinuouslyfor26monthsbeforethemeasurement.ThematureforestrespondedmorerapidlyandintensivelytoNadditionsthanthepineandmixedforests,andexhibitedsomesignificantnegativesymptoms,e.g.,soilacidification,Almobilizationandleachingofbasecationsfromsoil.ThepineandmixedforestsrespondedslowlytoNadditionsandexhibitednosignificantresponseofsoilcations.ResponseofsoilexchangeablecationstoNdepositionvariedintheforestsofsubtropicalChina,dependingonsoilNstatusandland-usehistory.

简介：Elevatedatmosphericnitrogen(N)depositionhasbeendetectedinmanyregionsofChina,butitseffectsonsoilNtransformationintemperateforestecosystemsarenotwellknown.WethereforesimulatedNdepositionwithfourlevelsofNadditionrate(N0,N30,N60,andN120)for6yearsinanold-growthtemperateforestinXiaoxing’anMountainsinNortheasternChina.WemeasuredgrossNtransformationratesinthelaboratoryusing15NtracingtechnologytoexploretheeffectsofNdepositiononsoilgrossNtransformationstakingadvantageofNdepositionsoils.NosignificantdifferencesingrosssoilNtransformationrateswereobservedafter6yearsofNdepositionwithvariouslevelsofNadditionrate.ForallNdepositionsoils,thegrossNH4+immobilizationrateswereconsistentlylowerthanthegrossNmineralizationrates,leadingtonetNmineralization.Nitrate(NO3-)wasprimarilyproducedviaoxidationofNH4+(i.e.,autotrophicnitrification),whereasoxidationoforganicN(i.e.,heterotrophicnitrification)wasnegligible.Differencesbetweenthequantityofammonia-oxidizingbacteriaandammonia-oxidizingarchaeawerenotsignificantforanytreatment,whichlikelyexplainsthelackofasignificanteffectongrossnitrificationrates.GrossnitrificationratesweremuchhigherthanthetotalNO3-consumptionrates,resultinginabuild-upofNO3-,whichhighlightsthehighriskofNlossesviaNO3-leachingorgaseousNemissionsfromsoils.ThisresponseisoppositethatoftypicalN-limitedtemperateforestssufferingfromNdeposition,suggestingthattheinvestigatedold-growthtemperateforestecosystemislikelytoapproachNsaturation.

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