Farmers growing corn in grain crop rotations are constantly evolving their soil fertility programs. Nitrogen management is of particular importance due to its relatively large requirement by corn and its elusiveness in soil. Some corn growers have pushed nitrogen application rates above University of Wisconsin Extension (UWEX) recommendations in pursuit of maximum yields. While striving for maximum yields may be a rational goal, farmers need to ensure they are not over-applying nitrogen and other inputs so as to minimize losses to groundwater and maximize corn production profits. This is the objective of eleven on-farm nitrogen rate and time of application comparisons conducted in Dane, Rock and Columbia Counties from 1999-2002.