Optimizing Plant Density and NPK Fertilization for Sesame Yield in Ghana’s Sudan Savannah

Abstract

Background: Sesame productivity in Ghana’s Sudan savannah is constrained by suboptimal plant density and fertilizer management, highlighting the need to identify optimum plant density–NPK fertilizer combinations that maximize yield and resource-use efficiency under nutrient-limited conditions. Aims: This study evaluated the effects of plant density and NPK (15–15–15) fertilizer application on the growth and yield of sesame (Sesamum indicum L.) under Sudan savannah conditions in Ghana to identify agronomic practices for improved productivity. Study Design: The experiment was conducted using a Randomized Complete Block Design (RCBD) with four replications. Treatments consisted of three plant densities (3, 5, and 7 plants/hill) under fertilized and unfertilized conditions. Methodology: The study was carried out at the CSIR–Savanna Agricultural Research Institute, Manga, Ghana. Sesame was planted at a spacing of 60 cm × 20 cm and thinned to the target densities after emergence. NPK (15–15–15) fertilizer was applied at 25 kg ha⁻¹ to fertilized plots. Data collected included days to 90% flowering and maturity, branches per plant, plant height, capsules per plant, 1000-seed weight, grain yield, and biomass yield. Data were analyzed using GenStat, and treatment means were compared using Fisher’s LSD at 5% significance. Results: Fertilization significantly improved sesame growth and yield across all plant densities. The lowest plant density (3 plants hill⁻¹) produced the highest grain yield and superior yield components, including branching, plant height, capsule number, and 1000-seed weight. Increasing plant density reduced grain yield and yield attributes due to greater inter-plant competition. In contrast, biomass production was highest at 7 plants hill⁻¹ under fertilization. Days to maturity were not significantly affected by either plant density or fertilizer application. Conclusion: Sesame productivity in the Sudan savannah of Ghana is strongly influenced by plant density and NPK fertilizer management. Lower plant densities combined with balanced NPK application enhanced grain yield and yield components, whereas higher densities increased biomass production. Adopting optimal density–fertilizer combinations can improve productivity, resource-use efficiency, and farmer profitability.