By Liz Morrison

It’s a sunny afternoon in early June, and Scott Walker is doing stand counts.

However, Walker, manager of Adams Seed in Wendell, isn’t crouching over a tape measure or measuring wheel. He’s counting plants from the air, using a drone. Later in the day, he’ll use his Phantom quadcopter to measure drown-out spots for replanting.

“The drone saves us a lot of time compared to random ground scouting,” Walker says. “It narrows down the issues, so we can find problems faster.”

Adams Seed is part of a vanguard of Minnesota ag service companies experimenting with commercial drone scouting. Walker offers free drone flyovers to his growers as part of his customer service. “I can spend time with customers and quickly see what worked and what didn’t.”

In addition to stand counts, Walker uses his $3,500 UAV (unmanned aerial vehicle) system to monitor diseases and pests, weeds, plant health and crop injury. This season — his second for drone scouting — he expects to fly about 10,000 acres.

FLIGHT CHECK: Scott Walker (right, in red shirt) and Chad Davison check the flight plan for a Phantom drone that will do a stand count on Davison’s soybean field. (Photo by Liz Morrison)

‘One more insight’
On this afternoon, Walker pulls up the drone flight plan on his iPad, and then sends the Phantom aloft to survey a 25-acre section of Chad Davison’s seed-soybean field. Flying at 150 feet, the Phantom takes more than 400 real-color photos with its embedded 4K camera, while Walker and Davison chat at the field edge.

Related:Flyover land

Planter down pressure was an issue this spring, says Davison, who farms near Tintah. He wants to know if the down pressure affected corn and soybean emergence and establishment.

In 14 minutes, the quadcopter buzzes back to the launch point with its payload of pictures.

Adams Seed subscribes to DroneDeploy, a web-based aerial mapping software platform, which will stitch all the drone images into a high-resolution map of the field in about two hours. The geo-referenced map will report precise plant counts and stand gaps, and if there were weeds in the field — there are none to speak of — the map would also pinpoint those.

In this way, Walker says, he hopes to give Davison “one more insight into how he is doing.”

HOW DRONE SCOUTING WORKS: Multi-spectral sensors on drones or manned aircraft capture images of a field. Drones flying at just under 400 feet (the maximum for unmanned flights) can produce imagery resolution of about 2.5 centimeters, which is on par with manned aircraft images. The flight images are stitched together and then processed to create a weed density map. A spray map can be generated and exported to compatible prescription mapping software, which produces an application map for the sprayer. (Source: Aglytix)

Quick troubleshooting
Drone scouting is especially useful for troubleshooting, Walker says. Last season, for example, a customer was spraying beans and noticed some “hot spots” where plants were stunted. The farmer asked Walker to fly the field and check it out.

“Within 15 minutes, I identified exactly where the problem areas were,” he says.

Walker used the GPS coordinates to walk to the spots where he sampled roots, and he found a serious soybean cyst nematode problem. The grower, who was surprised to find out that the field was infested, learned that he can’t plant a non-SCN (soybean cyst nematode) bean again.

Walker has used the drone in the same way to map and monitor parts of fields prone to iron deficiency chlorosis (IDC). Although problems like SCN and IDC will show up on yield monitors at harvest, it’s much easier to make a diagnosis when you still have plants to look at, he says.

Like yield maps, UAV images usually won’t tell you the reason for a problem, says Orlando Saez, CEO of Aker, an aerial crop monitoring service in Winnebago. His company created a mobile application called AkerScout, which uses drone imagery to improve scouting productivity. Drones quickly survey an entire field “and identify areas of risk that need to be scouted,” Saez says. “By highlighting impact areas for directed ground scouting, growers can do more in less time.”

Walker agrees: “If you can fly a field in half an hour, versus walking it for three hours, that’s a big savings.”

Morrison writes from Morris.

Editor’s note: See Morrison’s first drone story featured July 5, "Flyover land," by clicking on the "Related: Flyover land" link above.