简介：Along-termexperimentbeginningin1981inJinxianCountyofJiangxiProvince,subtropicalChina,wasconductedinapaddyfieldunderadoublericecroppingsystemwithfourdifferentfertilizationregimes,including1)nofertilizerascontrol(CK),2)balancedchemicalN,P,andKfertilizers(NPK),3)organicmanureusingmilkvetchandpigmanureintheearlyandlatericegrowingseason,respectively(OM),and4)balancedchemicalfertilizerscombinedwithorganicmanure(NPKM).Samples(0-17cm)ofthepaddyfieldsoil,whichwasderivedfromQuaternaryredclay,werecollectedafterthelatericeharvestinNovember2003fordeterminationoftotalorganiccarbon(TOC)andtotalnitrogen(TN)andfractionsoforganicCandN.ResultsshowedthatTOCandTNintheNPKMandOMtreatmentsweresignificantlyhigherthanthoseinothertwotreatments(CKandNPK).ApplicationoforganicmanurewithorwithoutchemicalfertilizerssignificantlyincreasedthecontentsofallfractionsoforganicCandN,whereaschemicalfertilizerapplicationonlyincreasedthecontentsofoccludedparticulateorganicC(oPOC)andaminoacidN.Inaddition,applicationoforganicmanuresignificantlyenhancedtheproportionsoffreeparticulateorganiccarbon(fPOC)andoPOCintotalC,andthoseofaminosugarNandaminoacidN(P<0.01)intotalN.Incontrast,chemicalfertilizerapplicationonlyincreasedtheproportionsofoPOCandaminoacidN(P<0.05).TherewerenosignificantdifferencesineithercontentsorproportionsofsoilorganicCandorganicNfractionsbetweentheNPKMandOMtreatments.TheseindicatedthatorganicmanureapplicationwithorwithoutchemicalfertilizersplayedthemostsignificantroleinenhancingsoilorganicCandNquantityandqualityinthepaddyfieldstudied.

简介：A15-yearfertilizationexperimentwithdifferentapplicationsofinorganicN,PandKfertilizersandfarmyardmanure(M)wasconductedtostudytheyieldandsoilresponsestolong-termfertilizationatQiyang,HunanProvince,China.Averagegrainyieldsofwheatandcorn(1672and5111kgha-1,respectively)forthetreatmentNPKMweresignificantlyhigherthanthose(405and310kgha-1)oftheunfertilizedcontrolandsingleinorganicfertilizertreatments.Comparedwiththecorrespondinginitialvaluesoftheexperiment,alltreatmentsshowedayielddeclineof9to111kgha-1year-1inwheatand35to260kgha-1year-1incorn,respectively,andasignificantpHdeclineof0.07to0.12pHyear?1,exceptforthetreatmentsPKandNPKM.Afterlong-termfertilization,thesoilorganicC,soilavailableP,exchangeableCa2+andMg2+andavailableCu2+andZn2+contentswerehigherinthetreatmentNPKMthaninthetreatmentsappliedwithinorganicfertilizeronly.ComparedtothetreatmentNPK,thetreatmentNPKM,wheremanurepartiallyreplacedinorganicN,hadapositiveimpactonarrestingthedeclineofsoilpH.Thisimprovedgrainyieldsofwheatandcorn,suggestingthatapplicationofNPKfertilizerincombinationwithfarmyardmanureisimportanttomaintainsoilfertilityandbufferingcapacityinredsoil.

简介：作为常规授精的一种选择评估器官的修正案的使用，沃土土壤的一个10年的实验在在Guadalquivir河山谷与化肥(NPK)和植物的堆肥(器官的化肥)使用的温室和室外的阴谋在一个庄稼旋转系统下面被进行，西班牙。土壤上的这二不同授精政体的效果物理性质被评估。玷污器官的碳(OC)，土壤体积密度(BD)，土壤水保留(WR)，可得到的水内容(AWC)，总数稳定性(作为)，并且玷污物理质量(德克斯特的索引，S)被决定。器官的化肥的使用增加了OC并且导致了的重要增加作为并且在与在温室和室外的阴谋的矿物质化肥申请相比的BD的减少。而温室阴谋出现了，室外的阴谋显示出最低BD价值象价值最高。在10年的实验的最后年里，S参数在器官的化肥阴谋是显著地更高的，特别为温室阴谋。在学习经期的结束，在在在在两个系统的治疗之间的领域能力(FC)的WR没有重要差别；AWC在矿物质在温室阴谋，但是更高也是类似的室外的阴谋。在矿物质化肥处理，在物理性质的小改进也与以前的集中的收割系统相比由于不太好攻击的耕种的利用被观察。物理土壤性质与土壤OC被相关。持续管理技术象器官的修正案的使用那样并且低或没有耕种改进了土壤物理性质，尽管有在管理的差别，那显著地逻辑地影响了结果。

简介：Soilmicrobialbiomassandcommunitystructuresarecommonlyusedasindicatorsforsoilqualityandfertility.Ainvestigationwasperformedtostudytheeffectsoflong-termnaturalrestoration,cropping,andbarefallowmanagementsonthesoilmicrobialbiomassandbacterialcommunitystructuresindepthsof0–10,20–30,and40–50cminablacksoil(Mollisol).Microbialbiomasswasestimatedfromchloroformfumigation-extraction,andbacterialcommunitystructuresweredeterminedbyanalysisof16SrDNAusingpolymerasechainreaction-denaturinggradientgelelectrophoresis(PCR-DGGE).Experimentalresultsshowedthatmicrobialbiomasssignificantlydeclinedwithsoildepthinthemanagementsofrestorationandcropping,butnotinthebarefallow.DGGEprofilesindicatedthatthebandnumberintop0–10cmsoilswaslessthanthatindepthof20–30or40–50cm.Thesesuggestedthatthemicrobialpopulationwashighbutthebacterialcommunitystructurewassimpleinthetopsoil.ClusterandprinciplecomponentanalysisbasedonDGGEbandingpatternsshowedthatthebacterialcommunitystructurewasa?ectedbysoildepthmoreprimarilythanbymanagements,andthesuccessionofbacterialcommunityasincreaseofsoildepthhasasimilartendencyinthethreemanagements.FourteenpredominatingDGGEbandswereexcisedandsequenced,inwhich6bandswereidentifiedasthetaxaofVerrucomicrobia,2bandsasActinobacteria,2bandsasα-Proteobacteria,andtheother4bandsasδ-Proteobacteria,Acidobacteria,Nitrospira,andunclassifiedbacteria.Inaddition,thesequencesof11DGGEbandswerecloselyrelatedtounculturedbacteria.Thus,thebacterialcommunitystructureinblacksoilwasstable,andthepredominatingbacterialgroupswereuncultured.