Corn School: How UAV Maps Make $ense for Nitrogen Application

The yield monitor is still the best barometer when it comes to assessing the value of crop inputs and agronomic strategies, but UAVs (unmanned aerial vehicles) are proving to be an important tool for in-season measurement and assessment of cropping strategies.

In this Corn School episode, AGRIS Co-operative agronomist Dale Cowan shares how he’s using UAV imagery to assess variable rate nitrogen strategies.

Cowan uses UAV imagery captured by his colleague Robyn DeBrouwer on June 9 to build soil-adjusted vegetation indexes (SAVI) to evaluate a field nitrogen trial where the east part of the field’s first application is 180 lbs actual N at sidedress compared to the west portion first application of 90 lbs N preplant.

“The value of the drone is we can fly any time, so we went back on June 24th and flew the field and we could see a vast improvement in growth,” says Cowan who used this flight to evaluate the impact and effectiveness of a second field-wide application of Agrotain treated urea.

While the imagery highlights improved growth and how it correlates with nitrogen application, Cowan notes that it also identifies areas of the field that did not respond to nitrogen, indicating that there are other limiting factors at work. “That tells you where else you have to go in the field and practice some good agronomy.”

The final analysis takes place when the yield map from the combine is layered over the two nitrogen treatments. “That will tell us whether we were more affective in nitrogen use efficiency and greater yields,” adds Cowan.

RealAgriculture will visit with Cowan again later this year to bring you the verdict.

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