Optimization of N, P, and K Fertilizer Rates for ‘IPB 13S’ Rice

Fertilizer recommendations for newly released rice varieties need to be optimized because nutrient requirements may vary among varieties and growing environments. ‘IPB 13S’ is a newly released rice variety developed by IPB University, and information regarding its optimal nitrogen (N), phosphorus (P2O5), and potassium (K2O) requirements is still limited. Therefore, this study aimed to determine the optimal rates of N, P2O5, and K2O fertilizers for ‘IPB 13S’ rice. The study was conducted from May to September 2024 at the Sawah Baru Experimental Farm, Dramaga, Bogor, Indonesia. Three fertilizer experiments (N, P2O5, and K2O) were arranged in a randomized complete block design (RCBD) with five fertilizer levels (0%, 50%, 100%, 150%, and 200% of the regional recommended rate) and three replications. Growth parameters, yield components, grain yield, and nutrient use efficiency were evaluated. Data were analyzed using analysis of variance, orthogonal polynomial analysis, and quadratic regression. The results showed that N, P2O5, and K2O applications significantly affected plant growth, yield components, grain yield, and nutrient use efficiency. Quadratic regression analysis identified optimal fertilizer rates of 170 kg N/ha, 53 kg P2O5/ha, and 71 kg K2O/ha, resulting in the highest predicted grain yield. These findings indicate that variety-specific fertilizer recommendations are needed to optimize grain yield and nutrient use efficiency in the ‘IPB 13S’ rice variety.