Many of the corn fields in Manitoba have emerged and for those fields that have not yet received their full complement of nitrogen fertilizer – now is a good time to make that application. There is no need to wait until corn plants are large before side-dressing with anhydrous ammonia or UAN solution. The time to apply is when the fields are suitable for traffic and injection.
One of our greater risks on non-tiled drained fields is that wet soil conditions in mid-June may hinder field applications of side dressed injected nitrogen. Although alternatives are available, they come with some potential damage and reduction in nitrogen efficiency. Broadcast urea to larger plants may leave some pellets in the whorl which cause leaf burn. Liquid 28-0-0 (UAN solution) may cause leaf burn when leaves are contacted. Dribble banding reduces leaf area affected compared to broadcast application, although dribbles tend to run into the whorl of larger plants. Surface applications to moist soil is subject to volatilization loss so Agrotain treatment may be necessary.
Submitted by: John Heard, Crop Nutrition Specialist, MAFRD