1. Response of Corn to N Fertilization in Fall, Spring, and (or) Summer

Precision farming technologies (remote sensing of canopy reflectance and yield monitoring) were used to study the response of corn after soybean to fertilizer N applied at different times in three field-scale trials in central Iowa in 1999. Weather conditions were unusually favorable for losses of fall-applied N and crop responses to N indicated that substantial losses occurred. Yields of corn could be maintained by adding a nitrification inhibitor or additional N, but the greatest profit was attained...