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Agronomy Talk


Identifying N-Deficient Areas in Your Corn Fields

Published on Wednesday, June 22, 2016

The first two to three weeks of June is when I usually conduct flights to secure high-res aerial imagery of corn fields to determine nitrogen (N) health and identify N-deficient areas. Generally, N loss will become more apparent in Missouri corn fields as they reach the Vn to V10 growth stage and leaves close over the row. 

Corn can respond favorably to rescue N applications from this growth stage all the way to tassel if required, so early detection is key to providing sufficient turnaround time for application. Nitrogen deficient corn has a light green or yellow color on the lower, more mature leaves. It can be detected by the trained eye, but can be spotted more accurately over a large area with aerial imagery or crop reflectance sensors. It is important to deploy sensor- and image-based tools after leaves close over the row. This minimizes the impact of soil light reflectance on images and allows the corn enough time to begin expressing its needs via color differentiation.

The University of Missouri’s online Nitrogen Watch, Beck’s FARMserver™ and Crop Health Imaging™ (CHI) program, and NVisionAg™ are all highly useful tools for evaluating field conditions and N needs. Feel free to contact your Beck’s dealer, seed advisor, precision farming field advisor, or myself to assist you in corn N assessment and management.

Author: David Hughes