A LONG-TERM FIELD EXPERIMENT WITH COMMERCIAL FERTILIZERS AND MANURE: I. Fertility levels and crop yields in a rotation of swedes, oats and hay
[摘要] Inafieldexperiment,conductedfrom1936to1957,arotationofswedes,oatsandhaywasfollowedandtreatmentsincludedcommercialfertilizersandmanure.Changesinthechemicalcompositionofthesoilduringtheexperimentincludedsignificantdecreasesinsoilorganicmatter,totalnitrogenandcationexchangecapacity.Innocasewastheinitialcontentofexchangeablepotassiummaintainedandalthoughchangesinadsorbedandeasilyacid-solublephosphoruswerenegligiblewithanumberoftreatmentsonlyoneresultedinasignificantincrease.Thetreatmentswereappliedintheswedeyearandyielddifferenceswiththiscropweregreaterthanforeithertheoatsorhay.Dataforthelattertwocropsindicatedthatwithmostofthetreatmentstherewasatendencyforyieldstodeclineastheexperimentprogressed.Thiswasnotthecasewithswedeswherevariationinyieldswithrotationcycleswasgreaterthanitwasinthecaseofoatsorhay.Therewasaconsiderableresidualeffectfrommanure,an...
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[效力级别] [学科分类] 农业科学（综合）
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