Optimizing Fertilizer Combinations for Enhanced Rice Growth and Yield

Abstract

Background: Rice is a major staple crop in Sierra Leone, but its productivity is constrained by poor soil fertility and inadequate nutrient management. Balanced fertilizer application may improve rice growth and yield; however, locally appropriate nutrient combinations require evaluation under field conditions. Aims: This study evaluated the effects of different fertilizer combinations on rice growth, flowering, and grain yield. Study Design: The experiment used a Randomized Complete Block Design with three replications. Place and Duration: The study was conducted at the Rokupr Agricultural Research Center experimental fields from June 2024 to May 2025. Methodology: Seven treatments were assessed: No fertilizer as control; NPK at 20–20–20 and 40–40–40 kg ha⁻¹; urea, SSP, and MOP; urea, TSP, and MOP; TSP applied by phosphorus dipping; and urea, TSP applied by phosphorus dipping, and MOP. Plant height and tiller number were recorded at 5 weeks after planting, together with days to 50% flowering and grain yield. Data were analysed using analysis of variance, and means were compared using Tukey’s HSD test at p = 0.05. Results: T-C3 produced the tallest plants, reached 50% flowering earliest, and recorded the highest grain yield (2.33 t ha⁻¹). T-4 was the next-best treatment for grain yield (2.16 t ha⁻¹) and recorded the highest mean tiller count. T-3 produced the fewest tillers and a lower grain yield than the unfertilized control. The observed performance of T-C3 was consistent with a balanced and synchronised supply of nitrogen, phosphorus, and potassium. Conclusion: Under the conditions of this one-year experiment, balanced NPK application improved rice growth and yield relative to the other treatments, although confirmation across additional seasons and sites is required before a definitive recommendation is made.