Drones will help NCDA&CS investigate damage to crops

By on April 15, 2021

On a recent spring day, the buzz of drones filled the air over one of N.C. State University’s field labs about five miles south of campus. Beside the big open fields, stood staff from the N.C. Department of Agriculture and Consumer Services, heads tilted up. An overcast sky helped them stare up to follow each drone as it took off for a flight one-by-one.

The small group of staff came from the department’s Structural Pest Control and Pesticides Division – specifically the Pesticides Section. They were there to see a sampling of three drones to figure out which one they may want to begin using to investigate pesticide damage in farmers’ fields. Dr. Gary Roberson, an NCSU professor and extension specialist in the Department of Biological and Agricultural Engineering was leading the test flights, along with two other NCSU researchers Jay Campbell and Justin Macialek.

Roberson specializes in machinery systems – basically anything a farmer may use to monitor and manage crops, including drones with cameras and sensors. He often refers to the drones as UAVs, which stands for “unmanned/uncrewed aerial vehicles.” He uses the drones to look for patterns or anomalies in a field – anything out of the ordinary – including drought, disease or insect damage. He’s also hosted a pesticide safety class for several years, and some of the Pesticides Section staff have attended, including deputy director Patrick Jones. Jones wondered if the same, or similar, technology could be used to also detect pesticide (or more specifically herbicide) drift damage to crops in fields.

Dr. Gary Roberson stands in front of NCDA&CS staff to begin drone demos.

“Patrick realized a bit of what I’m into, and he contacted me several months back, and asked me about setting up a program to get some advice on moving into UAV platforms,” Roberson said. “So it developed from there. We put together a proposal. The [N.C. Agriculture] department was gracious enough to fund it, and now we’re trying to put together the right tool set for [the Pesticides Section] to use.”

Specifically, the funds for Roberson’s drone research came from the N.C. Pesticide Environmental Trust Fund (PETF), after approval by the N.C. Pesticide Board. Money in the trust fund comes from companies that pay fees to register pesticide products in the state. The trust fund helps pay for many other environmental programs, and 27.5 percent of the fund each year (averaging $150,000) is divided among the agromedicine programs at NCSU, ECU, and NCA&T. 

Jones believes that with advice from Roberson, the Pesticides Section may be able to start using drones for drift damage investigations as soon as this growing season. Drift damage occurs when an herbicide from one field drifts over to another field nearby and damages the crop in the second field. (The fields would almost always have different crops with different requirements.) The farmer in the second field may notice damage such as yellowing and/or curled leaves, but an investigation is needed to know the true source. Sometimes a farmer’s damaged field may border fields of a few other farmers with a few other crops where different pesticides/herbicides were used. Sometimes there’s even a contaminated water source or some other explanation for the damage.

That’s why the investigation is so important. The Pesticides Section is tasked with determining the source of the damage as part of the division’s duty to protect people and the environment. If someone has incorrectly applied pesticides or herbicides, or contaminated a waterway – or whatever the case may be – then the division aims to find the problem. Jones said drones could especially help with drift damage cases.

“In a lot of our cases, we may have had application done on three sides of a field [by different people], but we hope drones will help us see the source better,” Jones said. “The damage can sort of display in a plume from the source. So this could obviously point us in the right direction.”

Jones said the plume of damage is sometimes hard to detect for an investigator at eye level. Herbicides can also drift in odd patterns, so an overhead view could make a big difference in an investigation.

“With dicamba drift for example, it’s just hard to tell sometimes,” Jones said. “We’re hoping with the aerial view we can see the pattern and source of the drift and just get a better idea of what’s going on.”

During the test flights, Roberson, Campbell and Macialek were able to show Jones and others in the Pesticides Section how a few drones fly and what their cameras, sensors and associated software can show. The combination of technology can produce a color-coded aerial image of a field to show damage, sort of like a heat map from an infrared camera. The images could be displayed immediately on a computer tablet that was linked to the drone in the air. Those images and data can be saved for review later.

“From the air we can see what the full extent of the damage is, how deep in the field it goes, how wide is the damage, the direction most likely that the damage came from. So there’s a lot of things we can extract from the imagery that we’re getting from these cameras on our UAVs.”

With special cameras, sensors and software, aerial images like this one can be combined to create an overall field picture, and colorization can be added in order to show intensity of damage to a crop. (source: Dwight Seal, NCDA&CS)

Jones and others were able to view samples of the images created, and they could ask lots of questions as they came up during the demonstration. With heads tilted up and eyes to the sky or the tablet, staff members peppered their questions all along the way. In addition to questions about equipment and software, logistical questions arose. Who can fly a drone? What are the rules about licensing? How long would it take to survey a field?

“We’re looking at some guidance on what to fly, what to fly with, meaning the cameras or sensors to put on them, how to process the data and how to manage the data after its been processed,” Roberson said. “Our mission is education. We’re just trying to help them decide what they need, and we’ll leave the investigation up to them.”

Roberson thinks there’s real promise in using drones to investigate drift damage. Jones does too. With the drones back on the ground and many questions covered, the group agreed to further discussion with at least one group video chat for more show-and-tell of how the software can work.

Roberson believes North Carolina is leading the way. He’s only aware of one other researcher at Mississippi State University looking into the same thing. As NCDA&CS moves forward with using drones for drift damage investigations this year, the state could be the first in the country doing so.

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