Nitrogen(N)applicationmayleadtonichesegregationofsoilammonia-oxidizingarchaea(AOA)andbacteria(AOB),therebyreducingthecompetitiveinteractionsbetweenAOAandAOBduetohigherammoniumsubstrateavailability.However,theadaptivemechanismsofAOAandAOBunderNenrichmentremainpoorlyunderstood.Stableisotopeprobing(SIP)microcosmincubationwasemployedtorevealcommunitychangesofactiveAOAandAOBinaloesssoilfromafieldexperimentgrowingpotatoesthatreceivednoN(control,CK),lowN(LN,75kgNha-1),andhighN(HN,375kgNha-1).Theresultsshowedthatthesoilpotentialnitrificationrate(PNR)wasmeasuredbyculturingofthesoilsamplesfromthefieldexperiment.SoilPNRwassignificantlyincreasedinHNby87.5%and67.5%comparedwithCKandLN,respectively.ComparedwithCK,the13C-amoAgenesofsoilAOAandAOBinHNhad2.58×104and1.55×106copies,representing1.6-and16.2-foldincreaserespectively.ItwasindicatedthatAOBdominatedsoilammoniaoxidation.Aphylogeneticanalysisofthe13C-amoAgeneshowedthatNapplicationsignificantlyincreasedtheproportionof54d9-likeAOAupto90%inHN,whiletheNitrososphaeragargensis-likeandNitrososphaeraviennensis-likeAOAwereinhibitedandcompletelydisappeared.NitrogenapplicationalsoresultedinthecommunityshiftofactiveAOB-dominantgroupfromNitrosospirabriensis-liketoNitrosospirasp.TCH711-like.OurstudyprovidescompellingevidencefortheemergenceandmaintenanceofactivenitrifyingcommunitiesundertheintensifiedNinputtoanagriculturalecosystem.
