Soybean is cropped under a two years rotational sequence with maize. Sorghum is broadcasted when the soybean leaves start to foliage around mid-October. This drought tolerant specie stay alive during the dry season and restart growing with the first rains. High biomass production of sorghum (> 15 tons of dry matter/ha) can be reached under such condition. His strong root system, ability to recycle K and to control weeds (allelopathic effect) makes this specie of first interest to enhance biological interactions. In addition, the sorghum could be harvested for grain and fodder source.