Modifying fertilizer rate and application method reduces environmental nitrogen losses and increases corn yield in Ontario

Nitrogen use in corn production is an important driver of nitrous oxide (N2O) emissions, and 4R (Right source, Right rate, Right time and Right place) fertilizer management practices have been proposed to reduce emissions. But managing fertilizer to reduce N2O emissions may increase nitrogen losses through other pathways such as leaching or ammonia (NH3) volatilization. This study used the Denitrification-Decomposition model to simulate corn yield and N2O emissions across a range of fertilizer management scenarios and soil-climatic zones in Ontario during 1986–2015. The results show that broadcasting fertilizer at the surface without incorporation had the highest environmental nitrogen loss, primarily NH3 volatilization. Injecting at planting or at sidedress reduced NH3 losses considerably, but caused more losses by nitrate leaching and N2O emissions. According to the model, reducing the fertilizer rate decreased leaching and N2O emissions without reducing corn yields. Using inhibitors led to a further reduction in N2O emission. Overall, our results emphasize that adjusting rates and application timings, improvement placement, and using inhibitors can mitigate N2O emissions by 42–57% and result in 3–4% greater yields compared to baseline scenario in Ontario corn production.