Simulating Nitrogen Losses from Minnesota Discovery Farms with Adapt-N.

Nitrogen fertilizer applications represent both a major environmental and economic impact within agricultural systems. These applications are done at a high financial cost to producers and excessive N is subject to aqueous and gaseous losses which can negatively impact air and water resources. Maximizing N application efficiency is ideal, but often difficult for crop producers to achieve. Recent development of user-friendly, adaptive models provide producers with an additional tool to manage N within their fields. One such model, Adapt-N, combines modeling of site-specific soil and crop biogeochemical processes with high-resolution climate data to provide adaptive and real-time information to producers. Models like Adapt-N also serve as a valuable resource to researchers interested in understanding, predicting and mitigating future N losses. The goal of this study was to determine the predictive accuracy of this model at select Minnesota farm sites. The modeled results were compared to measured yields of total N, from surface and tile drainage, from 2011, 2013, and 2014 at the selected study sites from the Minnesota Discovery Farms project. Out of the four modeled scenarios examined, we found that Adapt-N was reasonably accurate in its predictions, with the notable exception of deviations for fields that utilized either a manure N source or N-stabilizers.