Robot provides earlier cover crop seeding

NORMAL, Ill. — The timely planting of cover crops for maximum biomass has typically been limited to post-harvest or aerial inter-seeding, followed by the hope of rain for stand establishment.

The University of Illinois Research Park agtech startup EarthScience has developed an AI robot that can inter-seed cover crops in row crops for earlier establishment before the heat units disappear.

Dennis Bowman, U of I Extension digital agriculture specialist, demonstrated the newest version of the robot seeder at the recent Illinois Soybean Association Field Talk at Heartland Community College.

The robot features GPS and three small cameras on the front that identifies where the corn rows are and picks the patch to go through the field.

A cow catcher has been added to the newest version to help navigate through downed stalks and small weeds.

“The big advantage of this is that we can get out in the field earlier. The seeder is roughly 18 inches wide. It uses a simple spinning spreader system. The hopper will hold about 90 pounds of seed. At about a 30 pound seeding rate, we can 2.5 to 3 acres seeded per load,” Bowman said.

“It seeds three rows at a time really well. It’s low enough that it shoots out below the leaves. You can adjust the speed of the spinner to do that.

“I find seeds in the outside rows beyond that, as well. It will give pretty good coverage to three rows and you’ll get a little bit out a little farther, but helps even things out.”

Early Developmental Stage

Researchers are still working to achieve full autonomy.

“It will do a pretty good job of driving itself down the corn row, but if it runs into a big gap, it may try to move over a row, or if there is a major mess of down corn or weeds, it may get hung up,” Bowman said.

“Right now, the autonomy is pretty much to the point where they can fairly confidently do a ‘pitch and catch’ with somebody at both ends of the field. They don’t have the autonomy set up yet to turn it around at the other end to bring it back.

“The other challenge is it needs space to turn around, so we need a gap between the field rows and the headland to get the robot to turn around or we need no headlands to where the rows just open out.

“A team of four of them can do 40 acres in about three to four hours, and that’s how long the batteries last, as well. The battery is rechargeable, so you would want to probably have a rack of charged batteries.

“Unfortunately, these are not like the drone batteries that recharge fast. These are old-fashioned lithium polymer batteries that can take hours to recharge.”

The technology is not near the maturity of a drone systems where field boundaries can be set up to establish the route.

“This is a lot more hands-on at this point, but the robotic technology is something that is happening and this little company that’s grown out of the University of Illinois Research Park is one players in there,” Bowman said.

“One of the other projects I’m involved in is a weeding robot or some type of AI enhanced weeding system for horseradish producers. They saw the John Deere See & Spray and wanted to do something like that in horseradish.

“John Deere, Case, nobody is going to spend the money to develop a vision system that identifies horseradish. So, we’re using that as a test case to develop a specialty crop smart weed control system using AI to do that.”

Timing Research Trials

Cereal rye is the leading cover crop species planted in Illinois because it grows in most conditions.

“You can plant it just after harvest up until mid-November and probably still get a stand with cereal rye,” Bowman said.

“Planting cereal rye in front of corn can be a challenge, but there are a lot of other cover crop species out there that have other agronomic traits that we might want to take advantage of and they are not as aggressive.”

Bowman was part of a four-year cover crop trial utilizing about eight different species in a corn-soybean rotation.

“We used several different combinations, and the only one that worked year after year was cereal rye. Occasionally, we could get another species that might work, or we’d get a second flush of crown vetch the year afterwards, but cereal rye was the only one that works year in and year out,” he said.

“We were seeding those trials in mid-September, but you realize any cover crop seed that gets spread out, you really can’t consider it planted until it gets a rain on it, unless you have drilled soybeans that got soil moisture contact. Otherwise, if you’re just spreading it out there, until it gets moisture, it’s not really planted.”

The robot seeders were tested at the U of I Research Farms’ “Farm of the Future” site as part of the Artificial Intelligence for Future Resilience, Management and Sustainability and the Center for Digital Ag.

One trial strip was seeded with a drill after harvest on Nov. 3. In the adjacent test plots, robot seeding was done over several weeks with cereal rye and some spring oats.

“The cereal rye seeded by the robot started to head around May 10 and had good biomass, while the previous year’s cornstalk stubble was still visible in the drill-seeded cereal rye the next spring,” Bowman said.

“We had a good stand in the drilled cereal year. It just didn’t have the growth to it in the biomass that was where the robot seeded the cover crop was.”

Planting Dates

Nathan Johanning, U of I Extension educator, conducted cover crop trials that focused on planting dates across Illinois, planting cereal rye before soybeans and clovers after soybeans that also confirms the importance of earlier planting dates.

“He hasn’t had any robotic seeding or ultra-early planting dates in his study, but what a lot of this research does show is the advantage for earlier planting,” Bowman said.

Johanning planted cereal rye Sept. 29, Oct. 19 and Nov. 22. Seeding rates were 30, 60, 90 and 120 pounds per acre at each planting date.

With the September seedings, there was more biomass the next spring in the lowest seeding rate of 30 pounds per acre.

For the cereal rye planted Oct. 19, the higher seeding rates provided more biomass, Bowman said.

A similar study using balansa cover planted Oct. 19, Nov. 6 and Nov. 22. The earlier planting resulted in the most biomass.

“The early seeding with the lower seeding rates does really well,” Bowman said. “One of the things we’ve seen with the robot seeder is we can go with pretty low seeding rates. We’re looking at somewhere between 35 and 40 pounds of cereal rye seed that we’ve been using to test this system.

“It’s fairly new. Last year, our ‘Farm of the Future’ field was in soybeans, so we weren’t able to use the robots on it. It was all seeded by drone last year rather than with robots. We’ll seed into corn this year with the robot.

“You can see the advantage of biomass with the earlier seeded dates. It shows up pretty well in all of these studies. So, we’re looking at trying to get the cover crop out there, get it established earlier, take advantage of any rains we may get — this is an option to do that.”

Informational Resources

“For those interested in cover crops, I’d suggest that you check out the U of I farmdoc cover crop decision tool. The ag economists at farmdoc and the agronomists and computer folks have put together a cover crop tool,” Bowman said.

“You can put in your location, your planting date and your species, and it will estimate your growth and your biomass through the season, assisting with making termination decisions.

“This year, we’ll be feeding some of this ultra-early seeded cover crop data into that model to help ground truth it.”

“Our goal is to make the cost the same or less than any other seeding method that’s available,” he said.

“We don’t think farmers would be buying these themselves, but a company would buy a bunch of these and put them on a trailer with battery racks and chargers and contract out to plant your cover crops for you.”