Nitrogen Rate Decision Support For Kentucky Corn Grain Production

The proposed study design creates a unique plot layout that will offer an opportunity to increase our fundamental understanding of nitrogen fertilizer response and improve our ability to predict the correct nitrogen rate to achieve maximum yield, maximum return on nitrogen investment, or to minimize potential environmental impacts due to nitrogen leaching. This study includes six unique early season N rates, generating a range of V8 NDVI values along with responsiveness and yield potential data for each of those NDVI values. In addition, using a split plot design for the sidedress treatments allows us to assess total response to sidedress nitrogen at each sidedress rate, with small spatial variability. This data will improve sensor]based models that use yield potential and nitrogen responsiveness to generate spatially variable nitrogen recommendations. We hope to conduct this research over many years to continually add to the database allowing annual evaluation of nitrogen recommendation systems commonly used across Kentucky. This study will generate six nitrogen response curves, one for each preseason nitrogen rate, that look like the curve provided in Figure 2. For each site, we will the University of Kentucky recommended rate and the rates recommended by the commercial systems evaluated. We will be able to compare each of these recommended rates to the economic optimum, agronomic optimum, and environmentally optimum rates for each site. Across sites and years we will be able to report the error for each recommendation system compared to the three different targets. If we are able to continue this work for many years we will develop a database that farmers can use when deciding between current or future nitrogen recommendation systems available to them.