Soil Aggregate Stability(9)

土壤团聚体的经典文章

90JOURNALOFSUSTAINABLEAGRICULTURE

creasingorderofcationspromotingflocculationisCa+2(VanOlphen,1977).>Mg+2>K+>Na+ClayMineralogy

differentClayisoneoftheaggregatingfactorsinthesoil.However,theacteristicsdependingtionofclays,onitsmineralogy.Consideringthephysiochemicaleffectchar-isExchangethanothertionCapacityclaysthesmectiticclaysshouldbemoreefficientonaggrega-(CEC),becauseandoftheirconsequently,largespecificsurfacearea,highCationsubjectcapacity.opedtoslakingInaddition,thankaoliniteEmersonor(1964)illitebecauseshowedhighthethatphysiochemicalpressureswellingwhichclaysinterac-isaredevel-lessmorillonitebyentrappedairisreleasedbyswelling.However,fissuringofmont-swelling(1966)ofmayoccur,duetothecombinationofstressofentrappedairandandble,lowestablishedaggregateselectrolytethatconcentrations,under(LeBissonnais,unstablesoilsconditions,1996a).Conversely,McNealetal.highinmontmorillonitesuchashighSARarevaluestivelywhereasamountsstable,soilsandsoilswithhighhighcontentsin2:1clayinkaoliniteminerals,andbutsesquioxideswithoutorwithareunsta-rela-lowassociationofstrongstabilityofmontmorillonitekaoliniteoftheiraggregateswithhaveironanintermediatebehavior.Thefrequenttooxidesslaking.

mayberesponsiblefortheverypendsAnotherColemanonclaymechanismmined(1979),mineralogy.ofOsteretal.El-Swaifyaggregatebreakdown,chemicaldispersion,de-(1980),and(1976),ShainbergVanOlphen(1977),Aroraandtioncomparisonvalues).thatillitesThisareisthedueclaystothemostsmallersensitiveedge-to-facetodispersionandLetey(1984)deter-attraction(higherforcesfloccula-inoftotheotherclaysbecauseoftheirregularandterracedsurfacesflocculationtheilliteparticles.smectitebyAroraandColeman(1979)foundthatthesensitivitytothemicaceous.soil>dispersionkaolinite.NaHCO3wasinthedecreasingorder:illite>vermiculite>orderNevertheless,was:montmorilloniticVelasco-Molina>etal.(1971)foundthatthanHowever,atlowESPvalues,themicaceoushalloysitic-kaoliniticsoildispersedmore>cultClaythemineralogyhalloysitic-kaoliniticinfluencessoil.

soilaggregatestability,buttheeffectistheirtoassessbecausesoilsusuallycontainamixtureofclayminerals,diffi-sosense,behaviormontmorilloniteFrenkelisetmodifiedbytheassociationwithotherminerals.InthisThisnitebehavioristoal.(1978)reportedthattheadditionofsmallamountsofexplainedkaolinsoilsbythepromotesthedispersionofkaolininflocs.preventingparticles(faces)areadsorbedfactonthatthenegativelypositivelychargedchargedmontmorillo-1978).

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