Simulating maize yield and nitrogen leaching under smart fertilizer strategies in subtropical sandy soils

Abstract

Efficient nitrogen (N) management in Florida's coarse, N‐leaching‐prone soils is challenging because high N rates are often used to avoid deficiency. This study evaluated whether controlled‐release (CRF) and slow‐release (SRF) fertilizers can improve maize ( Zea mays L.) yield and reduce NO 3 –N leaching compared with urea under varying climate. A previously calibrated crop environment resource synthesis‐Maize model for the maize hybrid Pioneer P1870 was re‐evaluated with 2 years of field data from Live Oak, FL. The 2023 experiment included an unfertilized control, CRF, and SRF at 235, 314, and 392 kg N ha − 1 . In 2024, the same CRF and SRF treatments were repeated, and split‐applied urea at the same rates was added. The model reproduced above‐ground biomass, grain yield, and N uptake well ( d  = 0.81–0.99) and soil NO 3 –N with moderate skill ( d  = 0.57). The evaluated model was then used to run a 30‐year simulation (1995–2024) for CRF, SRF, and urea applied at 0–400 kg N ha − 1 in 50 kg increments, and outputs were analyzed by growing‐season rainfall and temperature categories. Rainfall, not temperature, significantly affected all variables. Across rainfall regimes, CRF gave the highest agronomic and environmental performance. At its source‐specific optimum N rate, CRF increased grain yield by ∼6%–7% and cut NO 3 –N leaching by ∼40%–45% relative to urea, whereas SRF reduced leaching (∼25% under normal rainfall) with smaller yield gains. Optimal N rates were highest for CRF, intermediate for SRF, and lowest for urea.