Mitchell Hora, a farmer in Washington, Iowa and owner of Continuum Ag, has been utilizing cover crops for 4 years. In the summer of 2019, he set up a two-acre field trial to experiment with more diverse cover crops in a wider, 60-inch, row spacing.
“With harvesting and then planting our cover crops, there is typically not much time in the fall to get cover crops to grow and get enough benefit out of them to make them feasible,” Hora said. “We wanted to interseed cover crops earlier in the year and a wider row configuration is opening up that opportunity.”
In June, the cover crop was seeded with a ground-driven push spreader; then in July, they added another experiment, aerial application of the cover crop mix with a drone, into standing corn.
“What I’m interested in is if this can be scaled up. Are we able to utilize the wide row configuration to maintain the same yields, but implement more diverse cover crops, to increase biodiversity and improve soil health?” Hora said.
Hora utilized a Rantizo platform on a DJI drone. It can hold up to 25 lbs of seed or two and a half gallons of liquid. “The mix we used was 35 pounds per acre. It took less than 10 minutes to apply the seed to the two acres,” Hora said.
The size of the tank on the drone limits the number of acres that can be covered per fill. Currently, the cost to use this application method is charged by the hour. “Currently, it’s isn’t quite cost-effective to seed cereal rye at scale because the seeding rates are so high, so the cost per acre is high,” Hora said.
The number of acres you can cover is also limited by the battery life of the drone. The fixed cost to this technology can add up as well. “You have the cost of the drone, the drone application equipment, the equipment to mix cover crops, multiple battery backups, and possibly a trailer and generator to keep charging the batteries,” Hora said.
An additional cost are any certifications that are needed, like a commercial drone pilot license.
Hora believes there is an opportunity with this technology. “For me, being able to do some of these trials on a small scale, using the drone really works. I don’t have great equipment to go and interseed the cover crop at small scale,” Hora said. “I also like the drone for more precise application: making sure we’re deploying the cover crop or other agronomic inputs, exactly where we are supposed to be.”
While the battery life is a limiting factor, it could be overcome. Currently, FAA regulations require one pilot to one drone.
“If the pilot could swarm, which is having one pilot for multiple drones, then five or more drones could continuously operate,” Hora said. “Then, there would be multiple drones up in the air covering acres while one is refilling. The swarm method would allow for more acres to be covered per hour, thus reducing the cost to the farmer."
This year Hora plans to replicate and expand the trial. “I will interseed cover crops again with the ground-driven rig, along with the drone, and this year, also try a rabbit tractor, which is a small robotic tractor to apply the cover crops,” Hora said.
“What I’m most interested in is being able to eliminate excuses in terms of implementing the principles of soil health, Hora said. “We know we need to implement diverse cover crops and using the drone was one of the ways we found we were able to do that.”