THE INFLUENCE OF KARITE (VITELLARIA-PARADOXA) AND NERE (PARKIA-BIGLOBOSA) TREES ON SORGHUM PRODUCTION IN BURKINA-FASO

Sorghum grain yields under the karite and the nere are reduced by an average of 50% and 70% respectively, in comparison with yields in the open field. Soil fertility, limiting primary production in the region, is at least as favorable under the tree canopies as in the open field. Reduced light intensity, to a minimum of 20% under the tree canopy, is probably largely responsible for low sorghum production under the tree canopies. Benefits from the tree products are more valuable than losses in cereal yields, explaining why trees are maintained on the agricultural fields. Pruning of tree branches, selection of (shade-) crops and tree selection could reduce crop yield losses but cannot be expected to increase tree- and crop production.