Soil Aggregate Stability(6)

土壤团聚体的经典文章

Research,Reviews,Practices,PolicyandTechnology87

TisdalldifferenceandmodelsamongOades,them1982;ismainlyElliott,the1986;numberOadesofstagesandWaters,ofaggregation.1991),andthechicalparticlesorderconfirm(Clay-P-OM).attachedismicro-aggregatesthehierarchicalorderofsoilaggregation.Thelowesthierar-Thesetoorganicmoleculeslessthan2(OM)mdiameter,byconsistingofclayaggregatesThenexthierarchicalorderisthecombinationpolyvalentofthesecationsmicro-(P)(<250mdiameter.(<2Them)nextintomicro-aggregates((Clay-P-OM)x)y,whichare<250bindm)intomacro-aggregateshierarchical(>250orderism).theFinally,bondingmacro-aggregatesofmicro-aggregatesthatbondsmicro-aggregatesintoclods(severalmmorevencm).TisdallandOades(1982)proposedwillhierarchyateachameter.were:stage.<0.2Inthemselvesarebuiltupinstageswithdifferenttypesofmtheir 0.2-2model,m thestagesofaggregationoraggregatestagesTheseofOadesaggregationandWaterswere:(1991)<20modified2-20m 20-250m >2000mdi-m 20-90themmodel, 90-250suggestingthatthemainmodelscanbeappliedgenerallytosoilswhereorganicm matter>250m.ceptbindingagent.Ingeneral,thesemodelsconfirmtheutilityoftheiscon-thethanoftheofhierarchical250micro-m,respectively.andmacro-aggregatesordersareGoodtoseparateaggregateslessandhigherwell-developedsoilstructureandisaredescribedstableas,‘‘onewhereallnaturewateroperateofandexternalmechanicalstresses’’(Dexter,1988).againstThehierarchicaltheactionsgreaterforsoildifferentstructuresizeindicatesclassesthatofdifferentaggregates.mechanismsofaggregationappearthan250m,andspeciallythosegreaterThus,than2macro-aggregatesmmindiameter,gateser20-250tobeheldmtogetherlargelybyfinerootsandfungalhyphae.Aggre-oxidesbyvariouscementsconsistincludinglargelyofpersistentparticles2-20mdiameterbondedtogeth-Recentand1995)studieshighly(Oadesdisorderedaluminosilicatesorganic(TisdallmaterialsandandOades,crystalline1982).mechanismshowedexample,inthattheformationencrustationandWaters,andof1991;Golchinetal.,1994;Golchinetal.,stabilizationplantdebrisofbythesemineralmicro-aggregates.particlesisanotherdiametermicro-aggregatesbristerencrustedbondedwithdiametersof2-20mconsistofparticles<2Formwithtogetherinorganicbycompounds).persistentorganicUnitsbondssmaller(plantandfungalde-andconsistofclayparticlesheldtogetherbyinorganicandthan2mindiame-willelectrostaticticleshavedifferentbonds.stability.Consequently,Dexteraggregatesofdifferentorganicsizecementsclassesstrengthoflowerhierarchicalorderare(1988)moredenseconcludedandhavethatcompoundpar-thethanparticlesofhigherhierarchicalorder.Healsoasuggestedhigherinternalthatifcallowestsoilordershierarchicalaggregatearesimultaneouslyorderofsoilstructureisdestroyed,theotherhierarchi-stabilityrequiresdestroyed.theanalysisConsequently,ofthebehaviorcharacterizationofparticlesofof

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