Sesbania rostrata as green manure for lowland rice in Casamance (Senegal)

Abstract

The stem-nodulating tropical legume, Sesbania rostrata, was grown for seven consecutive years for 35-42 days in the pre-rice niche of traditional Casamance (south Senegal) rainfed lowland fields under the management of both researchers and farmers. The incorporation of about 25- 35 Mg ha-1 of fresh green manure (GM) biomass resulted in an average N accumulation of 90- 150 kg N ha-1. Lowland rice-grain yields increased from 2 Mg ha-1 in weedy fallow control plots to about 4 Mg ha-1 where seed-inoculated S. rostrata was incorporated. Sesbania rostrata GM technology may contribute to increase rice production in Casamance and warrants to be extended to regions with similar conditions.