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1、Geoderma128(2005)63–79www.elsevier.com/locate/geodermaStorageoforganiccarboninaggregateanddensityfractionsofsiltysoilsunderdifferenttypesoflanduseBettinaJohna,TamonYamashitac,BernardLudwigb,HeinerFlessaa,*aInstituteofSoilScienceandForestNutrition,UniversityofGo¨ttingen,Bu¨sgenweg2,37077Go¨tti
2、ngen,GermanybDepartmentofEnvironmentalChemistry,UniversityofKassel,Nordbahnhofstr.1a,37213Witzenhausen,GermanycEducationandResearchCentreforBiologicalResources,ShimaneUniversity,Matsue,690-8504,JapanAvailableonline5January2005AbstractThetypeoflanduseandsoilcultivationareimportantfactorscontro
3、llingorganiccarbonstorageinsoilsandtheymayalsochangetherelativeimportanceofdifferentmechanismsofsoilorganicmatterstabilization.Ourobjectiveswere:i)toquantifythesoilorganiccarbon(SOC)andnitrogen(N)storageinsiltysoilsunderwheat,maize,grasslandandspruce,ii)todeterminetheSOCandNstorageinwater-sta
4、bleaggregatesofdifferentsize(b53Am,53–250Am,3250–1000Am,1000–2000Am,N2000Am)andindensityfractions(Mineral-associatedsoilorganicmatterN2gcm3(Mineral-SOM),freeparticulateorganicmatterb1.6gcm(freePOM),lightoccludedparticulateorganicmatterb1.633gcm(occludedPOMb1.6)anddenseoccludedparticulateo
5、rganicmatter1.6to2.0gcm(occludedPOM1.6–2.0))13andiii)toanalysethestabilityandturnoveroftheseSOCfractionsinthemaizesoilonthebasisoftheyCvalues.TotalSOCstocksdowntoadepthof60cmandincludingthehumuslayerwerelargeratthesprucesite(10.3kgC22m)ascomparedwiththegrassland,wheatandmaize(7to8Ckgm).Howe
6、ver,SOCstocksinthemineralsoilweresmallerintheforestsoilthanintheagriculturalsoils.Inthearablesoils,theaggregatefractions53–250Amand250–1000Amwerethemostabundantsizefractions,whereasaggregatesN1000Amweremostabundantinthegrasslandandforestsoil.TheSOCconcentrationandtheC/Nratioweregreaterformacr
7、oaggregates(N250Am)thanmicroaggregates(b250Am)inthefieldandgrasslandsoils.Atthemaizesitethepercentageofmaize-derivedCwassmallestinthefractionb53Amwith24%andsteadilyincreasedwithincreasingaggregatesizeto47%inthefractionN1000Am.Themajorpart(86–