Effects of Fertilizer and Soil Type on the Agro-Morphological Parameters of the Sorghum-Cowpea System in the Semi-Arid Zone of Burkina Faso

---

Résumé

Degradation of cultivated soils limits agricultural productivity and soil fertility. In Burkina Faso, the effect of soil type variability on cropping systems remains poorly documented, deserving further investigation. This study tests the effect of soil variability on sorghum-cowpea cropping system agronomic performance, with and without NPK fertilization. Two soil types (Lixisols and Cambisols) were tested at two fertilization levels (0 and 100% NPK) in a greenhouse using a split-plot design in vegetation pots. The agromorphological parameters of sorghum and cowpea were evaluated. Cambisols improve sorghum and cowpea agronomic performance more than Lixisols. Adding 100% NPK stimulates cowpea production (+40% and +15% above-ground and root biomass, respectively). In sole crop, Cambisols also improve sorghum above-ground biomass compared to
Lixisols (+13% and +4%, respectively). Our results show that the recommended 100 kg.ha-1 of NPK mineral fertilizer dose is not conducive to good cowpea root biomass in our sorghum-cowpea intercropping systems, as it is probably too high compared to the starter dose for cowpea in Lixisols. Thus, Cambisols could be a more competitive choice to obtain superior agronomic performance in terms of yield and crop quality (sorghum-cowpea).

Mots-clés

Soil type; biomass component; cropping system; sorghum; cowpea.