Simulation of Nitrous Oxide Emissions from Maize Fields Using the Precision Nitrogen Management Model.

Maize production is the biggest source of N₂O emissions from U.S. cropland but there is considerable uncertainty in these emissions estimates. Experiments to measure N₂O are expensive and/or labor intensive. Effective models can be validated using measured data and subsequently allow us to predict the impacts of a wider range of management practices and climate on N₂O emissions. We have developed the Precision Nitrogen Management (PNM) dynamic simulation model to estimate N leaching and gaseous losses (including total denitrification, N₂O emissions from nitrification and denitrification, and ammonia volatilization) from the root zone, above-ground biomass production, and crop N uptake in maize production systems. The calibrated model was tested by comparing simulated N₂O emissions to emissions data from multi-year studies representing a range of N management practices, soils and climate. Following model validation, simulations were run over many years to explore the role of land management on N₂O emissions