STRATEGIC FARMING: LET’S TALK CROPS! SESSION TALKS DRONES FOR FIELD IMAGES, DIAGNOSING PROBLEMS AND PESTICIDE APPLICATION

On March 19, Ryan Huffman, Iowa State University Digital Ag Innovation Lab senior research manager and Jorden Kuntz, founder of Biosphere Drone Solutions, joined UMN Extension crops educator Ryan Miller for a discussion about drones in row crop agriculture. This was the penultimate weekly episode of the 2025 Strategic Farming: Let’s talk crops! series of webinars.

Drones can be used to create aerial maps of farm fields, spray crops with crop protection chemicals or spread dry materials such as cover crop seed into a standing crop. Imagery-oriented drones provide a ‘bird’s eye’ view of agronomic crops during the growing season using various sensors to detect reflectance of visible light wavelengths (400-700 nm) and/or near-infrared wavelengths (750-1,000 nm). Software can then be used to stitch the series of images collected by a drone’s camera into a cohesive field map that can be used to inform where to focus one’s scouting efforts in a field.

Near-infrared light (750-1,000 nm wavelength) can provide additional information above and beyond visible wavelengths. Normalized difference vegetation index (NDVI) is a plant health index related to near-infrared wavelengths and an example of the type of high-resolution data that can be collected by drone. NDVI data can be used to inform management decisions in-season such as whether to replant sections of a field that have subpar plant stands or make a fungicide application to deal with a ground-truthed disease problem.

Drones designed for spraying crop protection chemicals can provide a bit more flexibility in-season than either a traditional groundbased or aerial spray rig. Ryan Huffman reasoned that, “When soil is saturated, it takes time for the soil to dry enough to get a 50,000 lb. sprayer across a field to make a herbicide application.” Research continues to compare the efficacy of drone and plane, or ground-rig pesticide applications and it is important to only use those pesticides that have label instructions for aerial applications to avoid undue risk. Software to run spray drones can adjust application speed, rate, droplet size, boom height and swath width. “Drone spray nozzles and spinner-type spreaders are typically located directly below the propellers. Droplet size is adjusted by the speed that the spinner spreader rotates, with the spinner essentially ‘slicing’ larger droplets into smaller droplets and faster spin speeds leading to smaller droplets,” shares Jorden Kuntz.

For those that missed this session, it is now available to view on YouTube at: z.umn.edu/StrategicFarmingRecordings.