Variable-Rate Nitrogen Management for Corn Production

SSMG-36 (T.A. Doerge)

Variable-Rate Nitrogen Management for Corn Production - Success Proves Elusive

Summary:

Adoption of variable-rate nitrogen (N) management by North American corn producers is low, despite the potential economic and environmental benefits of this practice.
A major obstacle is that recommended N fertilizer rates based on yield goal are often poorly correlated with actual economically optimum N rates.
Nitrogen response patterns are often field- and season-specific and can vary widely within the same field, further complicating adoption.
Side-by-side comparisons of uniform and variable-rate N management have revealed no consistent advantages for either strategy in yields achieved, profitability, whole-field N usage, or N-use efficiency by plants.
In the future, a better understanding of temporal variation in N soil test levels, better crop simulation models, and improved N sensing and application equipment may assist growers in capturing the benefits of site-specific N management.