Drones in Agriculture - Future of Targeted Weed Management

By Blake Jackson

Sprayer drones are drawing attention across farm country, but new research from the University of Missouri suggests they may not yet be ready to fully replace traditional ground sprayers for weed control.

Led by Kevin Bradley, a weed science professor at Mizzou, the study compared DJI Agras T40 drones with ground-based sprayers in soybean fields during the 2023 and 2024 growing seasons. Researchers evaluated spray coverage, off-target drift, droplet size, and overall weed control.

The results were mixed. Ground sprayers consistently provided more uniform coverage and larger droplets, which translated to steadier weed control.

Drones, while showing potential, often created smaller droplets and patchy coverage, particularly at the edges of their swaths. This led to variability in managing waterhemp, one of Missouri’s most persistent weeds.

Adjustments, however, improved drone performance. Flying at 8 miles per hour and 10 feet above the canopy offered better coverage, while increasing spray volume from 3 to 6 gallons per acre also enhanced consistency.

Importantly, drones achieved similar penetration into the soybean canopy as ground rigs, suggesting they could become competitive for targeted applications.

“This isn’t about saying drones can’t work it’s about understanding how to make them work better,” Bradley said. “If we manage factors like droplet size, swath width, and application speed, the technology can get closer to delivering the kind of results farmers expect from ground sprayers.”

While drones cannot yet replace ground rigs, they could reduce labor and target difficult-to-reach areas or weed escapes, potentially lowering herbicide use and environmental impact.

Next steps include testing pre-emergence herbicides, evaluating adjuvants, and comparing different drone platforms. With ongoing improvements, drones may play a meaningful role in managing herbicide-resistant weeds and expanding options for Missouri soybean growers.

Photo Credit: gettyimages-seregalsv