Nitrogen Timing and Form: Improving the Efficiency of Nitrogen Use.

Nitrogen recommendations in the Corn Belt do not include adjustments for the timing and form of the nitrogen. There are data published in the literature showing differences in availability of nitrogen for different timing and form of nitrogen. These data have not been incorporated into nitrogen recommendations, but more efficient use of nitrogen fertilizers would result from adjustments of nitrogen recommendations for the timing and form of the nitrogen. There is no commonly accepted procedure for incorporating adjustments into nitrogen recommendations. This talk will engage the audience in a discussion about how to incorporate the timing and form of nitrogen into an adaptive management system for estimating the timing and form of N that has the greatest probability of being the most efficient practice. We will discuss the most common corn rotations in the Corn Belt, corn after corn and corn after soybean, and fields with and without a manure history.