简介：

简介：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.

简介：MicrometeorologicalandmicroplotexperimentswereconductedinthefieldoffreshlyharvestedgreencaneinQueensland,Australia.ResultsshowedthathighammonialossoffertilizerNcouldoccurunderrelativelydryconditionswhenureaorcommercialproductofmixtureofureaandmuriateofpotashwereappliedtothesurfaceofsugarcanetrash.ThemoisturecontentinthetrashandthepHoffertilizerweretwoimportantfactorscontrollingtheprocessesofureahydrolysisandammoniavolatilization.MostoftheNinthesoilwastransformedtothenitratel-nitritefromafter70daysoffertilizerapplication.Nosignificantleachingwasfound.Urea-freeNfertilizershadhigherNrecoveriescomparedtourea-containingfertilizers.

简介：氨(NH3)挥发在土壤headspace是在碱的土壤，和NH3集中的氮损失的重要小径之一直接与NH3挥发被连接。氨被Fourier变换描绘中间红外线的photoacoustic光谱学(FTIR舞步)和在8501200厘米1的区域的二个典型吸收乐队被观察，它能在土壤headspace被用于NH3集中的预言。从诺思中国的碱的土壤在三个授精处理(没有N输入(CK)的控制，脲和涂的脲)下面涉及土壤孵化，壶和地实验。在土壤headspace的氨集中在每个实验被决定。在土壤孵化实验，NH3排出物被N输入开始，在白天2上到达了最高的集中，并且减少了到在在8d以后的CK测量了的水平，与在与涂的脲处理相比的脲处理的显著地更高的NH3排出物，特别在开始的4d期间。在壶实验的土壤headspace的NH3集中在孵化实验作为那显示出类似的动力学；然而，在在地实验的土壤headspace的NH3集中孵化和壶实验与那些表明了一个显著地不同的排放模式，并且为NH3集中有4-d延期。因此，在孵化的NH3集中和壶实验不能直接被用来象土壤温度和土壤骚乱一样在授精方法和申请率由于差别在这块地里为真实NH3排放建模。在控制版本的授精和参与以后在第二个星期内点亮灌溉，这被推荐涂的脲能被用来显著地减少从NH3挥发的观点的N损失。

简介：Anewwatersolublesurfacefilm-formingmaterialwasdevelopedanditseffectonreducingammoniavolatilizationfromanalkalinesolutionwasinvestigatedinlaboratory,Resultsshowedthatthenewfilmformedbythematerialwasnotonlymoreeffectiveinreducingammonialossthananyotherfilmstestedbutalsomuchcheaper.Theoptimumamountofadditionofthenewfilm-formingmaterialwasabout10timesthetheoreticalamounttoformamonomolecularfilm.Undertheexperimentalconditions,thenewfilmcouldeffectivelydepresstheammoniavolatilizationforatleast6days.Thecumulativeammonialossratesfordifferentfilmswerefittedtoasimplelogisticequation,andsomeimportantparameterssuchasthecumulativeloss,andthemaximumandaveragevolatilizationrateswerecalculated.Theeffectofdifferentfilmscouldbe,therefore,comparedquantitatively,indicatingthenewfilmwasmosteffectiveindepressingammoniavolatilization.

简介：Organicamendmentssuchasvermicompostandbiocharhavebeenreportedtoenhancesoilfertilityandcropproductivity.However,whethertheco-applicationofbothamendmentshassynergisticeffectsorwhethersuchbenefitsareaccompaniedbytheriskofgaseousnitrogen(N)lossinanagroecosystemremainsunknown.Asoilcolumnexperimentwithafullyfactorialdesignwasconductedusingthreelevelsofvermicompost(nodose,lowdose(1%,weight:weight),andhighdose(3%,weight:weight))withoutorwithbiochar(1%,weight:weight)toinvestigatetheireffectsonricegrowthandgaseousNlossacrossthecropgrowingseason.Ourresultsdemonstratedthatsynergisticinteractionsexistedbetweenvermicompostandbiocharinpromotingcropyield.Comparedwithbiocharamendmentalone,biocharcombinedwithvermicompostsignificantly(P<0.01)increasedriceyieldby26.5%–35.3%.However,highdoseofvermicompostsignificantly(P<0.01)increasedthecumulativeammonia(NH3)andnitrousoxide(N2O)emissions.Inthepresenceofvermicompost,theincorporationofbiocharamendmentsignificantly(P<0.01)decreasedthecumulativeN2Oemissionby14.1%–18.6%.ThelowestemissionfactorvalueofNH3andN2Owasachievedusingbiocharincombinationwithlowdoseofvermicompost.Thisstudyrevealedthatthecombinationofbiocharandmoderatedoseofvermicompostoffersanovelapproachtopromotecropproductivitywhilereducingtheenvironmentalrisk.