Applying rescue nitrogen

Aerial application of urea is an ideal way to apply rescue N. Our research found nearly identical yields for broadcast urea and urea dropped between rows in corn up to four feet tall, indicating minimal yield loss due to leaf burn. Because the pollination process in corn is so critical, I would hesitate to broadcast urea during pollination on a large scale, but my guess is that it would not cause any problem.

Aerial applications have the advantage that they do not need to follow rows. Since N loss is nearly always patchy, corresponding to where water flows in a field, an airplane can more easily and efficiently spread N on just the high-stress areas. These areas are easily visible from the air due to their light green or yellow-green color.

Rescue applications of N with high-clearance ground equipment is also an excellent option as long as stalks aren’t getting broken. At this point in the season, booms are the only feasible alternative. Drop tubes would be needed for N solution or ammonium nitrate applications, but not necessarily for urea. Earlier in the season, spinners provide an excellent way to cover large areas quickly with rescue N. If corn is more than two feet tall, urea is the preferred N source with a spinner due to higher burn potential with ammonium nitrate.