简介：Soilsamplesat0-10cmindepthwerecollectedperiodicallyatpairedfieldsinCorvallis,Oregon,USAtocomparedifferencesinsoilmicrobialandfaunalpopulationsbetweenorganicandconventionalagroecosystems.Resultsshowedthattheorganicsoilecosystemhadasignificantlyhigher(P＜0.05)averagenumberorbiomassofsoilbacteria;densitiesofflagellates,amoebaeofprotozoa;somenematodes,suchasmicrobivorousandpredaceousnematodesandplant-parasiticnematodes;aswellasCollembola.GreaternumbersofRhabditida(suchasRhabditisspp.),werepresentintheorganicsoilecosystemwhilePanagrolaimusspp.werepredominantintheconventionalsoilecosystem.TheomnivoresandpredatorsofAcarinaintheMesostigmata(suchasDigamasellidaeandLaelapid),andProstigmata(suchasAlicorhaiidaeandRhagidiidae),werealsomoreabundantintheorganicsoilecosystem.However,fungivorousProstigmata(suchasTerpnacaridaeandNanorchestidae)andAstigmata(suchasAcarida)weresignificantlyhigher(P＜0.05)intheconventionalsoilecosystem,whichsupportedthefindingthattotalfungalbiomasswasgreaterintheconventionalsoilecosystem.Seansonalvariationsofthepopulationdependedmostlyonsoilmoistureconditionandfoodwebrelationship.ThepopulationdeclinedfromMaytoOctoberforbothagroecosystems.However,higherdiversitiesanddensitiesofsoilbiotasurvivedoccurredintheorganicsoilecosysteminthedryseason.