Research Highlights

Drone technology enters a new field

By Carol Brown, USB database communications

Technology is in many aspects of farming. From autosteer implements and GPS guidance to the genetic codes refined in the tiny seeds, the technology era has taken agriculture by storm.

Another area being developed in the agricultural arena is the usage of unmanned aerial vehicles (UAVs) or drones. Researchers and farmers across the country are using UAVs more frequently to scout fields, saving the farmer time and energy.

“Using a drone for field scouting would be easier and more efficient than walking thousands of feet through 3-foot tall beans,” said Jim Lewis, a Maryland farmer and agriculture Extension agent. He worked with Carl Wise on a research project that explored drone technology improvement.

“I want to use this technology to bring value to farmers,” said Wise, the principal investigator on the project. “I’m a retired engineer and worked most of my life with remote sensing and drones for the military. I’m not a farmer but I want to bring my technical experience to them.”

Wise is studying ways that drones can help improve farmers’ bottom lines. Recently, he’s been using drone technology to scout fields for weeds, mainly palmer amaranth, and follow-up with precision herbicide spraying.

“I think we can improve the war on these weeds by working on a multi-step process,” Wise said. “Scout drones can be used to detect, locate, and in some cases, identify weeds. Then a precision spray drone would apply herbicide to individual weeds or specified areas.”

Lewis worked with Wise on the drone project on his farm and sees the potential in this technology.

“Using a drone to precision-spray individual weeds will be better than going out and manually pulling the troublesome weed to prevent seed spreading during harvest,” Lewis said.

UAV technology will help immensely with finding invasive weeds such as palmer amaranth, waterhemp and ragweed. It could help also with integrated pest management to complement the boots on the ground work being done now, Lewis said.

Scouting for problems and solutions

After Wise scouts a field for weeds with the drone, aerial images the drone captured are processed to identify different types of weeds in the field. Maps of weed types and locations are then used to establish shape files, which are transferred to a spray drone for herbicide application. The spray drone goes back over the field using the coordinates from the shape file to spray the weed or weed patch with herbicide.

“I’m looking at the smaller and mid-size fields: 100, 200 and up to 500 acres. It seems to be cost-effective in mid-sized fields and there’s a lot of fields this size,” Wise said.

Although herbicide or pesticide spraying via UAV has been approved in the United States by the Federal Aviation Administration (FAA), there are restrictions to which products could be used with the drone as well as the amount of product the drone can carry, which could vary by state. Other restrictions may be added by the Environmental Protection Agency (EPA). Spray drones will need to be handled by an applicator who is certified for both crop spraying and for flying a drone. 

Accuracy getting better 

Part of Wise’s research project, funded by the Maryland Soybean Board, was to explore the accuracy of the spray drones based on the shape file coordinates. The tests indicated that a 4-foot spray accuracy is expected using standard GPS, which is typical on lower-cost drones. 

Much higher accuracy can be achieved with RTK (real-time kinematic) technology, which the higher-end drones are likely to have. According to Wise, many other factors will influence the spray accuracy such as wind, altitude, spray pattern and down wash.

Wise cautioned that drone spraying success won’t be 100 percent. Logically, the probability of finding the weed goes up as it gets bigger. He believes that precision spraying the weeds when they are small, could amount to a 60 or 70 percent success rate. At maturity, weed detection and location should be nearly 100 percent. 

“With drone precision spraying, you can begin when weeds are 2-inches high, then hit them again at 4- to 6-inches. You could use a stronger herbicide so farmers might not need to purchase a pre-treated seed,” he said.

Using this system, Wise said, the amount of herbicide or pesticide applied to a field is greatly reduced, which could save farmers money with less impact on the environment. 

For more information on the research project, “Precision Drone Technology for Improved Crop Yield, Input and Environmental Impact,” visit the United Soybean Board’s National Soybean Checkoff Research Database.

Published: Nov 7, 2019