Soil Aggregate Stability(5)

土壤团聚体的经典文章

86JOURNALOFSUSTAINABLEAGRICULTURE

andThispaperdiscussesthemainprocessesandagentsaggregatestabilization,andreviewsthemainmethodologiesofaggregateusedtoformationdeterminecharacteristicsstability.influencesdatathestabilityoftheThemethodspaperemphasizesresults.Theused,theimportanceofconsideringthepossibilityduetotheoffactthatthemethodologyreviewedasanunifiedliterature,ingtheaggregatestabilityandexperienceFinally,basedonthepectsrangeofmethodologicalframework,whichincludesthemostinterestingweproposeas-aofthedifferentexistingsoils,methods.fromweaklyThisunifiedtostronglymethodaggregatedcouldbesoils.

usedforawideAGGREGATEFORMATIONANDSTABILIZATION

joinedSoilincludesandaggregationheldistheprocessbywhichaggregatesofdifferentsizesarecessesquently,occurtheprocessestogethermoreorlessofbycontinuously,formationdifferentorganicandandinorganicmaterials.Thus,itandstabilization.Inthefieldthesepro-less,theireffectsinteract,complicatingeventheiractdiscrimination.atthesametime.Conse-assomeauthorsreportthattheformationofsoilaggregatesoccursNeverthe-mainlyproducedaresultinorganicbyofphysicalforces,whilethestabilizationofsoilaggregatesis1993;andaorganicnumberoffactors,inparticularthequantityandqualityofforwettingsoilDalalaggregationandBridge,stabilizing(Dexter,1996).1988).However,agents(LynchandBragg,1985;Oades,Theclayphysicalflocculationforcesincludeisapre-requisite(temperateandtheandmechanicalregions),drying(semi-aridalimentarythecompressiveandsub-humidregions),freezingandalternatethawingactionofaswellasdryingactionofroots,andmetalants.Al,cationsThesuchinorganicasCa2+stabilizing,Fe3+,andagentssoilfauna,Al3+includemainlymainlyearthworms,clays,polyvalenttermitesagentscalciumtioncanbeandconsideredmagnesiuminthreecarbonatesmaingroupsand,oxidesgypsum.andhydroxidesofFeandbasedonThetheorganicstabilizing(Tisdalloftheorganicmatter:transient,temporaryandpersistentagebindinganddegrada-rapidlycharides.byandmicroorganismsOades,1982).ThetransientbindingagentsaredecomposedagentsarbuscularTemporarybindingandagentsincludearemicrobial-roots,hyphae,andplant-derivedparticularlypolysac-consistcations,ofresistantmycorrizalaromatichyphae,andsomefungi.Persistentbindingvesicular-agentshumicandstronglysorbedhumicpolymersmaterial(TisdallassociatedandwithOades,polyvalentmetalaggregatesmaterialsappeartobephysicallyprotectedwithinclay-1982).andsilt-sizedThesefragmentsThereareof(Skjemstadroots,severalhyphae,etal.,1993).Theyarederivedfromtheresistantmodelsbacteriaofaggregationcellsand(Edwardscolonies.

andBremner,1967;

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