A Framework for Improving Nitrogen Recommendations for Corn.

Improving Nitrogen Recommendations for Corn Corn covers the largest grain crop area (84 M harvested acres in 2011) in the United States and harvested acres have increased annually since 2007. Nitrogen is critical for optimum corn yields and few field crops have larger N rate recommendations. However, generally, only 50% of applied N is found in grain and stover. Current research shows that N losses during corn production contribute to air and water quality degradation; losses also represent economic costs to producers. A group of Midwestern, northeastern, and southern soil fertility and nutrient management specialists have been meeting under the auspices of the NEERA 1002 information exchange group to discuss ways to improve current and future corn N recommendations. Currently, land-grant N recommendations are based on generalized growing conditions, often by regions or soils. These recommendations have strengths and limitations based on their underlying assumptions and technologies. Improving N recommendations for corn will require management strategies that increase the uptake of N by corn (better fertilizer N use efficiency) and research that will better estimate and manage weather, soil type, and management effects on N availability during the growing season. The technologies used for better estimates of N rates may or may not be similar across agro-ecological regions. The NEERA 1002 committee will suggest a general framework to develop improved corn N recommendations