Growth and Nutrient Use Efficiencies of Yams (Dioscoreaspp.) Grown in Two Contrasting Soils of West Africa

Abstract

Fertilization is an important management strategy of yams (Dioscoreaspp.) especially when grown in degraded soils. A field study evaluated the leaf numbers, leaf area indices, crop growth, yields, and nitrogen (N) and potassium (K) use efficiencies ofD. alataandD. rotundatain Côte d'Ivoire when grown in two contrasting soils with and without fertilizer.D. alatahad a lower number of leaves per vine, although leaf area indices were higher, and the leaves were retained for a longer period than inD. rotundata. In all situations, the yields ofD. alatawere significantly higher, and fertilizers promoted growth of shoots, roots, tubers, and, thus, final yields especially in the low fertile savanna soil. The beneficial impact of fertilizer on yields was significantly lower in the fertile forest soils. The nutrient use agronomic efficiencies indicated the impact of both N and K in promoting yields especially under nonfertilized conditions.