Crop-specific fertilizer recommendations are necessary to improve yield and enhance food security in Ghana. This approach would help in improving crop productivity while maintaining a good soil health status. A new NPK fertilizer has been recently developed by the private sector with Nitrogen (N), Phosphorus (P), and Potassium (K) proportions of 11:22:21 respectively for improved cassava root yield. This study evaluated the right and economic rate of this fertilizer to apply for improved cassava productivity and farmer livelihoods. Rates of 0, 300, 400, 600, and 800 kg/ha of newly developed fertilizer were applied at Fumesua and Akumadan located in the forest agro-ecological zone, and at Ejura and Techiman located in the transitional agro-ecological zone of Ghana. The experiments were conducted in two growing seasons (May 2019 to April 2020 and May 2020 to April 2021). Increases in cassava growth were observed with the increasing levels of fertilizer at all locations and in the two growing seasons. Cassava yield was in the linear phase of the fertilizer response curve. It ranged from 28 to 52 tons/ha with the increasing fertilizer levels. Cassava in the forest agro-ecology had better growth and 25% more yield than other locations. Fertilizer rates between 0 and 400 were found to have the best yield returns and sufficient profit opportunities to sensitize adoption by financially constrained farmers. The results indicate that the newly developed fertilizer (11:22:21 N:P2O5:K2O) can improve cassava productivity in the inherently poor soils of Ghana. Keywords: fertilizer recommendation; plant nutrients; rainfall; agronomic practices; cassava productivity; root yield DOI: 10.7176/JBAH/12-18-03 Publication date:September 30th 202
