Effects of cutting dates on nutritive value of Napier (Pennisetum purpureum) grass planted sole and in association with Desmodium(Desmodium intortum) or Lablab (Lablab purpureus)

摘要

TheexperimentwasconductedatPaweAgriculturalResearchCenterlocatedNorthwesternEthiopiatoassesstheeffectsofdaysatcuttingonnutrientyieldandqualityofNapiergrass(Pennisetumpurpureum)plantedsoleandinassociationwithdesmodium(Desmodiumintortum)orlablab(Lablabpurpureus).Theexperimentaldesignwasasplitplotdesignwiththreecuttingdates(60,90and120daysfromplanting)asmainplotsandfiveplantassociations,namely,Napiergrasssole,desmodiumsole,lablabsole,Napiergrass/desmodiumandNapiergrass/lablabassociationsassubplots.The15treatmentswerereplicatedthrice.Significant(P0.01)effectsofdaysatcutting,plantassociationsandtheirinteractionswasobservedoncrudeproteinyield(CPY),invitroorganicmatterdigestibility(IVOMD),contentofCP,neutraldetergentfiber(NDF),aciddetergentfiber(ADF),aciddetergentlignin(ADL),ashandhemicellulose.TheCPY,NDF,ADF,ADLandhemicelluloseincreasedsignificantly(P0.01),whereasCP,ashandIVOMDdecreasedsignificantly(P0.01)withadvanceinplantmaturity.TheCPcontentofallthetreatments(includingthefactorsandtheirinteraction)wasabovetheminimumlevelof7%requiredforoptimumrumenfunction.CuttingNapiergrassandthelegumeassociationsat60and90dayscouldalsosatisfytheminimumCPcontentsof15%requiredforlactationandgrowth.RelativelyhighIVOMDvaluesof71.9,68.0and63.5%wererespectivelyobtainedat60,90and120daysofcuttingfortheNapiergrass/lablabassociation.Digestibleorganicmatteryield(DOMY)wasmaximumat120daysofcutting.ItwasconcludedthattheassociationofNapiergrasswithbothlegumespeciesgenerallyimprovedthenutritivevalueofNapiergrass,however,betterresultswereobtainedfortheparametersofnutritivevalueconsideredinthestudywhenNapiergrasswasplantedinassociationwithlablabforallcuttingdays.