Department of Plant Sciences

Growing population pressure and increasing food demands are expected to multiply manifold in the coming years. Combined with a steady increase of rice consumption per capita and a looming shortage of rice on the world market, the use of inland valleys in the savannah zone of West Africa for rice production is imperative. However, the rice productivity in such inland valleys is likely to vary with the field position, the level of water control and the use of fertilizers. This study investigates the potential productivity of rice in an inland valley of the sudano-guinean savannah zone of Benin. We compared two valley positions (flood-prone center vs. drought-prone fringes), two levels of water control (open vs. bunded plots) and two rates of fertilizer amendment in a 3-year field experiment. Rice yields were significantly higher in the valley fringe (3.8 Mg ha-1) compared to the valley bottom center (2.5 Mg ha-1). Bunding increased grain yield on average by 0.7 Mg ha-1, probably as a result of a better water retention in the plots and an increased N availability. Fertilizer application showed no significant effect on yield but tended to alleviate the negative effects of iron toxicity in the valley bottom lands.