Split application of nitrogen with 1/3 in the spring at or just ahead of planting and 2/3 side dressed as soon after and within 30 days of emergence as possible has been described by researchers as "the most efficient method" (bu corn/unit of N) of the 12 different methods that were studied.

Applying N when the corn is too tall for a hiboy or sprayer is really too late unless it is an emergency application. Late side dress may really green up the corn but will not be as effective (bu corn/lb N) as side dressing within the first 30 days after emergence.

Jim at Dawn