Site-specific applications of nitrogen in corn based on yield potential

Burdened by high production costs and increased environmental concerns, today's farmers are looking for new technologies that can help optimize their production efficiency. Site-specific farming is a technique to describe what some are calling the next major revolution in production agriculture which has the potential to address many of these concerns.

During the 1994 season, an experiment was conducted to document site-specific yield response of corn for different application rates of nitrogen fertilizer within soils with varying yield potentials. To accomplish this task, new technologies such as Global Positioning System (GPS), Geographic Information Systems (GIS), grain yield monitoring, and variable rate control were integrated into a overall system. A 22-acre no-till production corn field located in Milan, Tennessee was selected for this study. Prior to planting, an extensive soil survey was conducted and the field was classified based on varying levels of yield potential. Five different application rates of nitrogen were applied on the field using a variable rate applicator controlled by a laptop PC with control information being received in real-time from a GPS receiver and digital application map. Soil nutrient samples, leaf nitrogen samples, and plant population samples were collected through the season.

The GIS software in conjunction with the GPS receiver proved to be an effective method for managing spatially related information. Results indicate that variable rate application of nitrogen based on site-specific soil types within a field has the potential to increase the production efficiency for producers.