Effect of different levels of nitrogen fertilisation on yield and chemical composition of Brachiaria ruziziensis at bolting in West Cameroon

摘要

ThestudyoftheeffectofdifferentlevelsofnitrogenfertilizationonbiomassproductionandchemicalcompositionofBrachiariaruziziensisatboltingwasconductedattheUniversityofDschangin2008.Adevicecompletelyrandomizedblockcomparingsixdosesofnitrogenasurea(0,50,100,150,200and250kgN/ha)atboltingonplotsof8m2(4x2m)ofBrachiariaruziziensisinfourreplicationswasused.Theevaluationofthestemsleavesandwholeplantbiomasswasmadeoneachplotdependingonthelevelofnitrogenfertilization.Arepresentativesampleof1kgofwholeplants,takenduringmeasurementofbiomasswasseparatedintoleavesandstemsanddriedat60°Ctoevaluatethechemicalcompositionofdifferentpartsoftheplant.nbsp;Theresultsofthisworkhaveshownthatnitrogenfertilizationhaveinfluencedsignificantly(P0.01)thebiomassofBrachiariaruziziensisatbolting.ThebiomassofstemsandleavesingeneralhasincreasedwiththelevelofNfertilizationtoachievemaximumproductionwithfertilizationatthedose200kgN/haatbolting(6.11±0.87,7.13±0.76and13.24±0.70tDM/harespectivelyforleaves,stemsandwholeplant).FertilizationhasinfluencedsovariablechemicalcompositionofBrachiariaruziziensis.Theconcentrationofcrudeproteinwassignificantlyincreasedwithnitrogenfertilization.FertilizationhadnosignificanteffectonOMDandMEofleavesandwholeplantofBrachiariaruziziensis.Inthestemsitwasloweredcomparedtounfertilizedplants.TheDMandfibrecontentwasnotinfluencedbynitrogenfertilization.FertilizationatboltinghasdecreasedcarbohydrateconcentrationinplantsofBrachiariaruziziensis.nbsp;Thisstudyshowsthatfertilizationwith200kgN/haincreasesbiomassofBrachiariaruziziensisatbolting,andalsoinfluencedvariablythechemicalcomposition,andthusconstitutethemaximumleveloffertilizerforthisplantatthisphenologicalstageintheselatitudes.