Soil Aggregate Stability(7)

土壤团聚体的经典文章

88JOURNALOFSUSTAINABLEAGRICULTURE

differentsizemicro-aggregates.

hierarchicalorders,suchasmacro-aggregates,andclay-andsilt-FACTORSAFFECTINGSOILAGGREGATESTABILITYsidered:Twomainfactors(1)soilgroupsprimaryoffactorscharacteristicsaffectingorsoilinternalaggregatefactors,stabilitycanbecon-discusstotivity,thetheinfluencesoil.Amongofthethesoilprimarycharacteristics,weandwill(2)reviewexternalandmineralogy,EC;typeaggregateCaCOofcations,electrolytesodiumadsorption(concentration,ratio,thusSAR;electricalpH,etc.),conduc-clay3andgypsum,theoneage,stability.Amongtheexternalorganicfactors,matter,weandwillFediscussandAltheoxidesclimate,onwithmustthetheothernotbiologicalconsiderfactors,andtheagriculturalmanagement.However,parameters.oneparameterwithoutconsideringtheinteractionsInternalFactors

andItvariablesdispersiblehasbeenshown(Goldbergclaythatet(micro-aggregatewetaggregateal.,1988).stability)stability(macro-aggregatearerelatedtosimilarstability)soilElectrolyte

micro-aggregatesIthasbeensuggesteddropisproducedthatdisintegrationprimarilyofthesoilmacro-aggregatesintoetNa/(Caal.,impact,1992a)beingbythewettingactionandbywater-andcompositionindependentofelectrolyteconcentration(EC)(Shainbergnoted+Mg)0.5]).Barzegaret(speciallyal.(1994b)sodiumandLevyadsorptionandTorrentoratio,[SAR(1995)=bility,howeveranadverseeffectofsodicity(SAR)onmacro-aggregatesta-(>250showing(<250m)thatsodicitydecreasedtheamountofmacro-aggregatesstabilitym).ESPfromnotedTheand0.3tobyslightconsequentlyincreasedtheamountofmicro-aggregates1.3%,LevyadverseeffectofexchangeableNainmacro-aggregatewhileandTorrentotherewas(1995)noeffectwasonlyinthenoticeablerangeatincreasinglyteThe(Quirkconcentrationmainfactors(EC),controllingthesolutionclaydispersion/flocculationfrompHandthesodiumarethe1.5electro-to5%.Amézketa,and1992;Schofield,Amézketa1955;andShainbergAragüés,and1995a,Letey,b).

1984;Suarezadsorptionetal.,1984;ratiosionLowandelectrolyteswellingandconcentrationsconsequentlyandthehighlossSARofvaluessoilstructure.produceTheclayadverse

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