Ciclaje de nutrientes en un banco de proteína de matarratón (Gliricidia sepium)

摘要

ChangesinthenutrientstatusofaproteinbankofGliricidiasepiumweredeterminedovera12monthperiodinthefourthyearafterthetreeswereestablished.ThemeasurementsweremadeattheElHaticofarmintheCaucaValley,Colombiaon6plotsrepresentingthreeprovenancesfromthecollectionattheOxfordForestryInstitute,establishedfromseedatdensitiesof10,000and40,000plants/ha.Resultsfromeachoftheprovenancesweresimilarandweretreatedasreplicationsinthestatisticalanalysis.Duringthe12monthstudytherewereincreases(P=0.001)insoilpH(from6.6to7.07),soilorganicmatter(2.57to3.56%)and(P=0.18)inavailablephosphorus(133to154mg/kg).Theharvestedyieldoffreshforage(leaves,petiolesandgreenstems)averaged66.3tonnes(15.2tonnesdrymatter)andthatwhichfellonthesoilsurfacewas3.38tonnesdrymatter.Thebalances(kg/ha/yr)ofnutrients(Qf+Qv+Qh-Qi;whereQfiscontentinsoilatendofthetrial,Qvisinharvestedforage,QhisinfallenleavesandQitheinitialcontentinsoil)were:997forN,50.3forP,341forK,282forCaand125forMg.ItisconcludedthataswellasfixingconsiderableamountsofatmospericNandcontributingtothesoilcarbonsink(20%increaseinsoilorganicmatterinoneyear),GliricidiasepiumalsocirculatesandrecyclesconsiderableamountsofP,K,CaandMgwhichwouldappeartobethereasonwhyforageyieldshavebeenmaintainedwithoutaddedfertilizeroveraperiodof7years.