Quantifying nitrogen release behavior of enhanced efficiency fertilizers in rainfed cotton through field‐based and combustion methods

Abstract The effectiveness of enhanced efficiency nitrogen fertilizers (EENFs) depends on how well the nitrogen (N) release synchronizes with crop demand. A 2‐year (2024–2025) mesh‐bag study was conducted to quantify N release from six N fertilizer sources under field conditions. The release trajectories were well described by three‐parameter logistic model ( R 2 > 0.94). By 63 days after fertilization, urea + polymer‐coated urea (PCU 43‐0‐0) in 50:50 ratio released the greatest proportion of total N, reaching 91% in 2024 and 86% in 2025. In contrast, PCU (42‐0‐0) released 46% in 2024 and 57% in 2025, whereas PCU (41‐0‐0) released the lowest across both seasons (37% in 2024 and 34% in 2025). The N release from the field‐based method was significantly correlated with the combustion method ( r = 0.958, p < 0.001). The findings of this study provide field‐based information for selecting EENF source with a release pattern that better aligns with cotton ( Gossypium hirsutum L.) N demand.