Effect of Nitrogen and Zinc Fertilizer Application on Growth and Yield of Rice (Oryza sativa L.)

Nitrogen (N) and zinc (Zn) are critical nutrients that often limit yield in flooded rice systems. To investigate the effects of varying N and Zn fertilizer rates on the growth, yield, and nutrient use efficiency of rice (Oryza sativa L. cv. Sinthuka) during both dry and wet seasons through pot experiments conducted at the Yezin Agricultural University farm. The experiment was designed as a 4×3 factorial arrangement with three replications, evaluating four nitrogen application rates (0, 40, 80, and 120 kg ha⁻¹) and three zinc application rates (0, 10, and 20 kg ha⁻¹). Nitrogen application significantly enhanced plant height, tiller number, and grain yield. While the maximum grain yield was achieved at 120 kg N ha⁻¹ during the dry season, no statistically significant differences were observed between 120 kg N ha⁻¹ and 80 kg N ha⁻¹ across key growth and yield parameters, indicating that 80 kg N ha⁻¹ is likely the optimal rate for sustainable productivity in both seasons. Zinc application at 10 kg ha⁻¹ significantly increased filled grain percentages (71.20% compared to 61.97% in the control) and exhibited a synergistic interaction with nitrogen, further enhancing grain yield. The highest yields were recorded with 120 kg N ha⁻¹ combined with 10 kg Zn ha⁻¹ (71.05 g hill⁻¹) in the dry season and 80 kg N ha⁻¹ combined with 10 kg Zn ha⁻¹ (43.43 g hill⁻¹) in the wet season. Therefore, the application of 80 kg N ha-1 and 10 kg Zn ha-1 might be the appropriate rate to maximize the rice production. Considering the increased grain yield of rice, nitrogen rate 80 kg N ha-1 and zinc rate 10 kg Zn ha-1 should be used in this study area.