Evaluation of fertilizer recommendation for Sesame (Sesamum indicum L.) in Sudan Savannahs of Nigeria

Sesame (Sesamum indicum L.) is an important oilseed crop in the Sudan savannahs of Nigeria, but its productivity remains low due to inadequate fertilizer management. This study evaluated the effects of five nitrogen fertilizer rates (0, 30, 60, 90, and 100 kg N ha-1) on growth, yield, and economic returns of sesame during the 2024 rainy season at Bayero University Kano Research Farm. The experiment was laid out in a randomized complete block design with three replications. Phosphorus and potassium were applied uniformly at 30 kg ha-1 each across all treatments except the control. Results showed that plant height, number of branches per plant, number of capsules per plant, 1000 seed weight, seed yield, oil content, and harvest index increased significantly (p<0.05) with increasing N rates up to 90 kg N ha-1, beyond which no significant differences were observed. The highest seed yield (1085.7 kg ha-1) was recorded at 90 kg N ha-1, representing a 157% increase over the control. Oil content increased from 46.2% in the control to 51.8% at 90 kg N ha-1. Economic analysis revealed that application of 90 kg N ha-1 gave the highest net return (₦944,514 ha-1) and benefit-cost ratio (3.64). Agronomic efficiency and nitrogen use efficiency decreased with increasing N rates, indicating diminishing returns at higher application rates. The quadratic response model (y = -0.0353x² + 10.4374x + 415.7663, R² = 0.99) best described the yield response to nitrogen application. Based on economic and agronomic considerations, application of 90 kg N ha-1 is recommended for optimal sesame production in the Sudan savannahs of Nigeria. This finding provides valuable guidance for sesame farmers to maximize productivity and profitability in this agroecological zone.