Using Simulation Models and High-Resolution Climate Data for Adaptive Nitrogen Management in Maize.

Denitrification and leaching losses of nitrogen (N) result from dynamic and complex interactions among weather, soil hydrology, crop water and N uptake, and management practices, and result in high variability in annual crop N needs in maize (Zea mays L.) production. Several studies have corroborated that weather impacts the soil N pool early in the growing season and contributes to the well-documented variability in economic optimum in-season N rates for maize. Increased climate variability will make the need for adaptive N management more compelling. Using dynamic simulation models as nutrient management tools represents a major step forward in the management of agricultural nutrient flows. We have developed the Precision Nitrogen Management (PNM) model and use it to improve N use efficiency and reduce N losses in maize production. It can provide recommendations for in-season N applications by accounting for the impact of early season weather on soil N dynamics and the soil N pool available for crop N uptake. Using the PNM model, we generated adjustments to the recommended in-season N rates for maize in the 2004 - 2007 growing seasons for 16 different climate regions in New York State. For 2008 and beyond, we have developed a web-based version of this tool, titled ADAPT-N, that automatically accesses newly-developed high resolution climate data at the 4 km scale at the Northeast Region Climate Center. These recommendations allow for greatly increased precision of N management and improved response to the effects of climate variability.