Optimizing Nitrogen Rates in the Midwestern United States for Maximum Ecosystem Value.

The importance of corn production to the Midwestern United States cannot be overestimated. Yet, high production requires nitrogen (N) fertilization, which can carry costs to environmental services such as water quality. Therefore, a tradeoff often exists between the production of both corn yield and water quality services. We employ the GWAVA-S and CERES-Maize models to investigate the nature of this tradeoff while testing the Simple Analytical tradeoffs framework. First, we estimate the current levels of yield and water quality production in Northeastern Iowa and Southern Minnesota at the 1 km², county, and regional scales. We then construct an efficiency frontier from optimized nitrogen application patterns to maximize the production of both yield and water quality. Results highlight the context dependency of this tradeoff, but show room for increasing the production of both services to the benefit of all stakeholders. We discuss these results in the context of spatial scale, biophysical limitations to the production of services, and stakeholder outcomes given disparate power balances and biophysical contexts.