Abstract Efficient nitrogen (N) fertilizer management is essential for advancing maize production, particularly in sandy soils of subtropical regions like Suwannee Valley, Florida, where NO 3 ─N leaching poses environmental risks. A 30‐year simulation using a calibrated and evaluated Crop Environment Resource Synthesis‐Maize model assessed the effects of N sources, rates, application timing, planting dates, and water regimes on grain yield (GY) and NO 3 ─N leaching. Results showed that moderate to high N rates (202–404 kg ha −1 ) achieved the highest yields but increased NO 3 ─N leaching by 33%–38% compared to the recommended N rate (RNR) (269 kg N ha −1 ). Early planting (March 1–22), split N applications, and precise irrigation (80%–90% of maximum available water MAW) improved yield up to 25% and reduced NO 3 ─N leaching up to 30%. Under rainfed conditions, a 50% reduction in the RNR led to a negligible change in yield but decreased NO 3 ─N leaching by 35%, while it reduced yield by 15%–30% under irrigated conditions. Optimal practices, including splitting N into five times, irrigation at 90% of MAW, and March 8 planting, achieved the highest yields (10,182–11,925 kg dry matter ha −1 ) and the lowest NO 3 ─N leaching (60–63 kg ha −1 ). Combined analysis revealed that the interaction between N rate and water management was significant for yield, N uptake, and NO 3 ─N leaching ( p < 0.01). Irrigation at 90% of MAW with 100% of the RNR maximized yield (12,422 kg ha −1 ) and N uptake (340 kg ha −1 ), and reasonably lower NO 3 ─N leaching (40 kg ha −1 ). These findings highlight the critical role of integrated management practices to improve GY while minimizing environmental impacts.
Birhan et al. (Thu,) studied this question.