Soil Aggregate Stability(19)

土壤团聚体的经典文章

100JOURNALOFSUSTAINABLEAGRICULTURE

aggregatesThisthixotropicproducedagebyhardeningcultivationof(Molopeclaysalsoetal.,contributes1985a;tostabilizesoilingSeasonalMullaseasonhavevariationsalsobeenand/orobservedvariations(Perfectinaggregateetal.,1990a;stability1987).

Caronwithinetal.,a1992c;grow-however,etal.,1992;LehrschandJolley,1992).Thesetemporalvariations,tothetimearefactorattributed(aging).toclimaticfactorsandtobiologicalfactorsratherthanBiologicalFactor

roots,Theciallysoilbiologicalmicrobes,systemandsoilisanotherfauna.Theysoil-formingformaggregatesfactor.ItincludesplantAllactivities,biotamacropores,influenceand(3)theirsoilbutstructuretheirmajorby-productsthrough:roleis(Jastrow(1)inthethestabilizationandofsoilpores,structure.espe-andorganismsMiller,themselves,(2)theirstructureThemaineffectsofthemostimportantbiological1991).

componentsonsoilsuchwillbediscussedinturn.However,readersarereferredtoreviewsMillerasLynchandBragg(1985),GuptaandGermida,(1988),Jastrowandsionof(1991),theimportanceOades(1993),ofsoilKandelerbiotaonsoilandstructure.Murer(1993),forawiderdiscus-Roots

(1982).TheyareconsideredinpositivethepresenceSeveralauthorsofrootsevidencedastemporarybindingagentsbyTisdallandOades(Habibetthatmacro-aggregatestabilityisimprovedintolocalizedstableeffectmacro-aggregates,onsoilaggregational.,1990;PojasokandKay,1990b).Theirevenconsistwhenon:the(1)rootenmeshingfineparticlestodecomposabletheaxissoilofenvironmenttherootandarounddrawingtheroots,soilreorientingisdead;clayparticles(2)dryingparallelthelationwormsintherhizosphere;organicresidues(5)providingtosoil;(4)foodsupportingparticlestogether;forsoila(3)supplyinganimals,largemicrobialpopu-1996);insolutionandand(6)thereleasingmesofaunapolyvalent(Tisdallcations,andOades,increasing1982;concentrationsOades,such1993;asTisdall,earth-ofionscrops’Rooting(Pojasok1996).differentpattern,andabilitiesrootKay,functions1990b).

inmodifyingandphysiologysoilstructureare(ChanresponsibleandforthegrassesMonocotyledenousformerarebetterthancerealsplantsinstabilizingaresuperioraggregates,todicotyledenousduetothefactplantsHeenan,thatandthe1993).

containamuchgreaterrootbiomass(LynchandBragg,1985;Oades,Onthecontrary,Caronetal.(1992a)reportedashort-termdecreaseinsoil

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