Contributions of leguminous cover crops in yam production systems in Southeastern Nigeria: I Biomass production and weed suppression

Abstract

A study was conducted from 2003 to 2005 at Umudike, South-eastern Nigeria, to evaluate ten legume cover crops for biomass production and weed suppression. There were eleven treatments which consisted of ten legume species (Mucuna pruriens utilis, Mucuna pruriens IRZ, Mucuna georgia, Mucuna veracruz, Aeschynomene histrix, Pueraria phaseoloides, Stylosanthes capitata, Chamacrista rotundifolia, Centrosema pubescens and Crotolaria ochroleuca) in comparison with natural fallow (grass cover). The experiment was laid out in a randomized complete block design with three replications. On the average, biomass production reached peak values at 4 months after planting (MAP) in Mucuna georgia, Mucuna pruriens IRZ, Mucuna veracruz, Centrosema pubescens and Crotolaria ochroleuca and 6 MAP in Aeschynomene histrix, Peuraria phaseoloides, Chamacrista rotundifolia and Stylosanthes capitata. Weeding significantly enhanced legume biomass production by 1407% in Aeschynomene histrix, 458% in Centrosema pubescens, 237% in Pueraria phaseoloides and 274% in Chamacrista rotundifolia. With hoe weeding at 4 weeks after planting, weed dry matter was significantly lowest in Chamacrista rotundifolia and Pueraria phaseoloides at 4 MAP whereas at 12 MAP, weed dry matter was lowest in Aeschynomene histrix plot.

Key words: Cover crops, biomass, yam, weeds, Nigeria