会计学ContentEnhancedsoilfertilityandhigherbiodiversityfoundinorganicplotsmayrenderthesesystemslessdependentonexternalinputs.增强有机系统中的土壤肥力和提高土壤生物多样性可能会导致对这些系统较少的外部投入。2、DOKTrialDescriptionFourfarmingsystemswerecompareddifferingmainlywithrespecttofertilizationstrategyandtheconceptofplantprotectionmanagement.Theorganicsystems(BIODYNandBIOORG)Theconventionalsystem(CONFYMand)CONMIN//3、ResultInputofnutrients,pesticides,andfossilenergytotheDOKtrialsystems.Potatoyieldsintheorganicsystemswere58to66%ofthoseintheconventionalplots(Fig.1),mainlyduetolowpotassiumsupplyandtheincidenceofPhytophtorainfestans.Winterwheatyieldsinthethirdcroprotationperiodreachedanaverageof4.1metrictonsperhectareintheorganicsystems.Thiscorrespondsto90%ofthegrainharvestoftheconventionalsystems,whichissimilartoyieldsofconventionalfarmsintheregion(8).Differencesingrass-cloveryieldsweresmall/CerealcropyieldsunderorganicmanagementinEuropetypicallyare60to70%ofthoseunderconventionalmanagement,whereasgrasslandyieldsareintherangeof70to100%.ProfitsoforganicfarmsinEuropearesimilartothoseofcomparableconventionalfarms.Appropriateplantbreedingmayfurtherimprovecerealyieldsinorganicfarming.TherewereminordifferencesbetweenthefarmingsystemsinfoodqualityThemaintenanceofsoilfertilityisimportantforsustainablelanduse.Inourexperimentalplots,organicallymanagedsoilsexhibitgreaterbiologicalactivitythantheconventionallymanagedsoils.Incontrast,soilchemicalandphysicalparametersshowfewerdifferences.Soilaggregatestabilityasassessedbythepercolationmethodandthewetsievingmethodwas10to60%higherintheorganicplotthanintheconventionalplots.Thesedifferencesreflectthesituationasobservedinthefield,whereorganicplotshadagreatersoilstability./SoilpHwasslightlyhigherintheorganicsystems(Fig.2B).Insoilsoftheorganicsystems,dehydrogenase,protease,andphosphataseactivitieswerehigherthanintheconventionalsystems,indicatingahigheroverallmicrobialactivityandahighercapacitytocleaveproteinandorganicphosphorus.Phosphorusfluxthroughthemicrobialbiomasswasfas