Monitoring winter wheat growth at different heights using aerial imagery
Date
2021-02-09
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Agronomy Journal
Abstract
Drones (unmanned aerial vehicles) provide another system to mount sensors for measuring plant characteristics. For winter wheat (Triticum aestivum) this can include evaluating stands and making nitrogen (N) recommendations. Timing these flights and adequate camera resolution (based on flying height), must be known before applying tasks. This study observed six winter wheat planting populations (222, 297, 371, 445, 494, and 544 seeds m–2) at three different heights above ground level (30, 60, and 120 m) over three growing seasons. Plant populations could be separated at all growth stages and heights flown but were easier to separate right after emergence (GS11). In the spring, additional tillering caused the higher populations (371–544 seeds m–2) to have similar normalized difference vegetative index (NDVI), much like the final yields. Comparing changes in NDVI between flights was also successful in separating high and low planting populations, with inverse relationships in the fall and spring. A random forest classification of tiller counts by NDVI measurements ranked change in NDVI between stages as the most important compared to single flights. As separation and classification was successful at the lowest camera resolution (120 m), it can be possible for scouts to collect whole field imagery for analyses prior to deciding on split N applications.
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This article was originally published in Agronomy Journal. The version of record is available at: https://doi.org/10.1002/agj2.20539.
© 2020 The Authors. Agronomy Journal published by Wiley Periodicals, Inc. on behalf of American Society of Agronomy
This is an open access article under the terms of the Creative Commons Attribution-NonCommercial License (http://creativecommons.org/licenses/by-nc/4.0/), which permits use, distribution and reproduction in any medium, provided the original work is properly cited and is not used for commercial purposes.
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Miller JO, Adkins J. Monitoring Winter Wheat Growth at Different Heights Using Aerial Imagery. Agronomy Journal. 2021; 113:1−10. https://doi.org/10.1002/saj2.agj220539