Precision Agriculture Research
Determining Nitrogen Application Rates

The goal was to provide 21.4 kg N ha-1 from fertilizer and residual soil N for each Mg ha-1 of corn yield goal. Adhering to this underlying goal, N applications were varied spatially based on the following criteria:

U treatment plots: uniform yield goal (11.8 Mg ha-1), soil N credit was the average of soil N values from all plots.
V1 treatment plots: uniform yield goal (11.8 Mg ha-1), soil N credit was dependant on the zone.
V2 treatment plots: yield goal and soil N credits were zone dependant.

Rate varied within each plot based on the zone boundaries determined by the treatment for that particular plot.

Note: A portion (56 kg ha-1) of the N required was applied through the sprinkler irrigation system during mid vegetative stages.

Soil N was measured on a grid in 2000 and in the plot centers in 2001-2003.