InteractionsofN,PandKfertilizersinsoil-plantsystemsarewidelyrecognized.Thisstudyfocusedonthetransformationsofmonocalciumphosphate(Ca(H2PO4)2)(MCP)withco-applicationofammoniumandpotassiumfertilizersinthreedifferentsoils.Theresultsshowedthatafter1dincubationalargeportionoftheMCPappliedinthepaddy,calcareousandredsoilsbecamethewater-insolubleformandtherecoveriesofPappliedasOlsenPvariedgreatlyinthesethreesoils.Applicationofammoniumsulfate((NH4)2SO4)(AS)orpotassiumchloride(KC1)reducedWSPsignificantlyinthesoilswithASmoreeffectivethanKC1inthecalcareoussoil,whilethereverseoccurredintheredsoil.Meanwhile,inthepaddysoil,co-applicationofthetwofertilizersreducedWSPmorethanwhenthefertilizerswereappliedinpidually.Theco-applicationofASwithMCPinthepaddyandcalcareoussoilssignificantlyreducedOlsenP,buttheoppositeoccurredintheredsoil.Theexperimentontheeffectofdifferentaccompanyinganionsshowedthattheammoniumfertilizers(PNC1andPNS)reducedWSPmoreeffectivelythanthecorrespondingpotassiumfertilizers(PKC1andPKS)inthecalcareoussoilduetothedifferenceofthecations,whereasintheredsoil,thechloridesreducedWSPmoreeffectivelythanthesulfates.Overall,co-applicationofammoniumorpotassiumfertilizerswithMCPsignificantlydecreasedavailabilityofPfromMCPduringitstransformationinsoils,especiallywhenMCPwasappliedincombinationwithammoniuminthecalcareoussoil.
