Effect of soil amendment with Gliricidia sepium and Tephrosia vogelii biomass on maize yield at Makoka in Malawi

Abstract

Several studies assessing the effect of leguminous tree biomass such as Gliricidia sepium and Tephrosia vogelii on maize yield have been undertaken. There has been limited knowledge on the efficacy of leguminous tree biomass on maize yield when grown after a crop with a high nitrogen (N) demand. One such crop is cotton. The current study was undertaken with the objective of determining the efficacy of either gliricidia or tephrosia biomass application with or without inorganic fertilizer on maize yield cultivated after cotton and also after land fallowing. Significant variations in grain yield (P = 0.0038) were obtained in the second cropping season (2016/17) but not in the first cropping season (2014/15), except maize stover (P < 0.0016). Significant variations were also obtained during 2016/17 season with respect to maize cob yield (P < 0.0041) and stover yield (P = 0.0062). Grain yield was significantly higher where inorganic fertilizer was applied with gliricidia biomass than where inorganic fertilizer was applied alone. A similar trend was also observed during the first cropping season though not significantly different. Lower grain yield was obtained when cotton crop preceded maize crop indicating a need for a higher N fertilizer dose for maize crop cultivated after cotton. Application of a half dose of inorganic fertilizer together with gliricidia biomass showed high and steady grain yield over the yield obtained when inorganic fertilizer was applied alone. It is concluded that soil fertility amendment with inorganic fertilizer is needed after a cotton crop. Also, the use of a half dose of inorganic N fertilizer with gliricidia was effective, suggesting that a full dose with gliricidia biomass was rather surplus to the requirements for maize production. Our study shows that farmers can save nearly half of the inorganic N fertilizer required by maize under gliricidia-maize system.