Effect on production of sugar cane and on soil fertility of leaving the dead leaves on the soil or removing them

摘要

Anexperimentwascarriedoutonalow-fertilitypodzolicsoilinanexistingsugarcaneplantationinfirstratooncanethathadbeenharvested5monthsearlier.Theobjectivewastostudytheeffectonproductionofthesugarcaneandonsoilfertilityofleavingthedeadleavesonthesoilsurfaceorremovingthem,atvaryinglevelsofapplicationoffertilizerN.Thetreatmentsinasplit-plotdesignwere:50,100and150kgN/ha;andremovingallthedeadleavesfromthesoilsurface(notrashmulching)andleavingthedeadleaves(withtrashmulching).Althoughtheexperimentalperiodonlylasted6monthsthetreatmentsappearedtohavemarkedeffectsbothontheproductivityofthesugarcaneandmoreimportantly,fromthepointofviewofsustainability,onthefertilityofthesoil.Therewerestrongindicationsthat:leavingthedeadleavesonthesoilsurfaceincreasedbiomassproduction,improvedsoilfertilityandincreasedtheamountofcarbonsequesteredinsoil;applicationofureatothesoil,uptoalevelof150kgN/ha,increasedbiomassyieldandthenutritionalqualityofthesugarcaneforanimalfeeding;theeffectsofmulching(leavingthedeadleavesonthesoil)andofNfertilizationweremostlyadditive,indicatingtherewasnoapparentconflictbetweenthesetwomanagementpractices.