Adapt-N: A Web-based Application for Nitrogen Management in Maize.

Current N management tools for maize production do not directly account for the dynamic behavior of soil N, limiting our ability to more efficiently manage N. The dynamic behavior of soil N, particularly early season soil N, contributes to the well-documented variability in economic optimum maize sidedress N rates. Tracking changes in soil N could, therefore, provide a means for adjusting maize sidedress N rates and improving N use efficiency in maize production systems. The dynamic behavior of soil N in maize production can be quantified with a well-calibrated dynamic simulation model of the soil-maize system. 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 or PNM model, composed of a dynamic simulation model of soil N transformations and soil N/water transport (LEACHN; Hutson, 2003) linked to a maize N uptake/growth model (Sinclair and Muchow, 1995). Our goal has been to apply the PNM model to improve N use efficiency and reduce N losses in maize production. To achieve this goal, we have used the PNM model to generate adjustments to the recommended in-season N rates for maize in the 2004 - 2007 growing seasons for different climate regions in New York State. For the 2008 growing season and beyond, we have developed a web-based interface (Adapt-N) for the PNM model that growers, crop consultants and extension staff can access to determine in-season N application based on early season weather and user inputs provided via the interface. Key attributes of the Adapt-N tool include the user-friendly design of the interface, and the capacity to automatically access high resolution climate data (Northeast Regional Climate Center at Cornell University) that allows for farm- or field-specific in-season N recommendations.