Effets de deux rotations a base de mucuna et soja sur la fertilite d’un sol ferrallitique degrade et le rendement de maïs.

In order to determine the effect of two legumes (mucuna and soybean) on soil fertility and yield of maize, an experiment was conducted over two growing seasons in the derived savannah on Rhodic ferrasol in the southern region of Togo. During the first growing season, plots of mucuna, soybean and maize received phosphorus at the rate of 0 and 30 kg per hectare in a randomised complete bloc design with four replications. During the second growing season, each of the previous plots was divided into two (split-plot) to account for nitrogen application at the rates of 0 and 45 kg per hectare. All plots were sown in maize in the second season. Results indicated that phosphorus was efficient on this soil as it gave a 62,4%surplus of maize yield as compared to the check, with agronomic efficacy of 32,67. The residue of mucuna contributed to increase the average yield of maize by 67% as compared to the mono crop system, whereas those of soybean increased maize yield by 37,5 %. The effect of nitrogen application was significant of on maize dry matter, but not on grain yield. Mucuna and soybean weregood previous crops, but the adoption of mucuna, the best previous crop, would result in the loss of one growing season because mucuna is not edible