简介：Nutrient-poor,sandysoilsformtheprevailingsubstrateatpost-miningsitesoftheLusatianregion(Brandenburg,Germany)andpresentachallengeforvegetationdevelopment.Westudiedtheorganicacidquantityandcompositionofthreecommonlyoccurringpioneerplantspecies,thelegumesLotuscorniculatusL.andTrifoliumarvenseL.andthegrassCalamagrostisepigeios(L.)Roth,todetermineifplantgrowthandexudationdifferedwith(non-sterilizedsoil)andwithout(sterilizedsoil)anindigenoussoilmicrobialcommunity.Weinvestigatedwhetherorganicacidswerefoundintherhizosphereandsurroundingsoilandwhetherthisinfluencednutrientmobilization.Thisstudyconsistsoflinkedfieldinvestigationsandagreenhouseexperiment.Plantsweregrowninthegreenhouseineithersterilizedornon-sterilizedsandysoilfromareclamationsiteintheLusatianmininglandscape(WelzowSu¨d,EastGermany).Aftersevenmonths,theplantbiomass,rootmorphology,organicacids,andwater-solublenutrientsandrootcolonizationwitharbuscularmycorrhizalfungi(AMF)anddarkseptateendophytes(DSE)wereanalyzed.RootsofallthreeplantsinthefieldandgreenhouseexperimentswerehighlycolonizedwithAMF.CalamagrostisepigeiosandT.arvensehadasignificantlyhighercolonizationfrequencywithDSEthanL.corniculatus.Thequantityandcompositionoforganicacidsstronglydifferedamongplantspecies,withthehighestnumberoforganicacidsfoundforL.corniculatusandlowestforC.epigeios.Thequantityoforganicacidswasgreatlyreducedinallplantsundersterilizedsoilconditions.However,thecompositionoforganicacidsandplantgrowthinsterilizedsoilwerereducedforbothlegumes,butnotforC.epigeios,whichhadahigherbiomassundersterilizedconditions.Changesinnutrientconcentrationsinthefieldrhizospheresoilrelativetothoseinthecontrolweremeasurableaftersevenmonths.Whilethespectrumoforganicacidsandthegrowthoflegumesseemedtobedependentonahighly