Received: 14-11-2020 / Accepted: 18-01-2021
Thepurposeofthisstudywastodeterminethepropercombinationofchemicalandorganicfertilizersforimprovingtheyieldandqualityoforange.ThesubstitutionsofchemicalfertilizerbyorganicfertilizerwereappliedforSanhorange7-8yearsoldinBacQuang-HaGiangandCS1orange5-6yearsoldinCaoPhong-HoaBinh.Theexperimentsincluded4treatments,inwhichthecontrolapplied100%chemicalfertilizerasthelocalfarmerused.Intheotherthreetreatments,thechemicalfertilizerwassubstituted25%,50%and75%withorganicfertilizers.TotalN,P2O5andK2O/haofalltreatmentswereequal.Indetail,thecontrolofSanhorangeinBacQuang-HaGiangwasapplied390kgN+ 350kgP2O5+ 440kgK2O/ha;thecontrolofCS1orangeinCaoPhong-HoaBinhwasapplied300kgN+ 300kgP2O5+ 356kgK2O/ha.Theresultsindicatedthatthesubstitutionof25%ofchemicalfertilizerbyacommercialorganicfertilizerincreasedtheyield.Theaverageyieldoftwoyearswas34.2ton/haofSanhorangeand15.8ton/haofCS1orange.Thereplacementofchemicalfertilizerbyorganicfertilizerhasimprovedcarotenoid,totalsugarcontentbutitreducedvitaminC.Inaddition,soilpHrose0.2-0.3whileapplying25-75%oforganicfertilizer;OMandNmineralcontentsoftreatmentwith75%organicfertilizerincreased0.4-0.5%and3.7mg/100grespectively,inBacQuang-HaGiang.pHofsoilincreased0.1-0.7inCaoPhong-HoaBinhcomparedtocontrol.