In West African agro-ecosystems, soils are inherently low in soil organic carbon decreasing the capacity of soils to
sustain crop productivity. Woody Residues instead of being burnt or exported out of the cropping systems, can be
managed to optimize soil organic carbon build-up, nutrient cycling and crop productivity. The aim of this study
was to determine the effect of woody residue amendments from Piliostigma reticulatum (D.C.) Hochst associated
with sorghum-cowpea intercropping on the soil residual property and crop productivity. The investigation was
carried out in two experimental sites in the Sudano-Sahelian (Gampela and Kulungu) area of Burkina Faso (West
Africa). The experimental design was organized into four replicates consisting of two treatments of woody
residue amendments: amended (WR+) and unamended (WR-) soils. The results for both sites showed an overall
significant increase in numbers (+ 35%) and biomass (+ 64%) of cowpea nodules. The root and aerial biomasses
at the flowering stage of cowpeas were significantly improved in amended soils (WR+) by 26% and 44%,
respectively compared to unamended soils (WR-). In addition, the WR+ treatment increase significantly cowpea
and sorghum yields by 41% and 25%, respectively, as well as water use efficiency (+ 40% and + 26%, respectively) compared to the WR- treatment. Moreover, our results exhibited a strong correlation (r = 0,95) between cowpea nodular biomass and sorghum grain yields, reflecting more contribution of cowpea ecosystem services (facilitation and complementarity) for associated sorghum productivity. However, despite favorable soil conditions (soil water and organic carbon content) that occurred by WR input, it was not sufficient to improve soil residual total nitrogen and available phosphorus. The woody residue management associated with cereallegume intercropping is a promising option to sustain crop productivity in Sahelian agro-ecosystems.

Acrisols Lixisols Nodulation Woody residues Crop yields Cereal-legume intercropping