On-farm cover crop research finds answers

LEXINGTON, Ill. — Cover crop successes and challenges were featured in a recent field day at the Illinois State University Research Farm.

Nicholas Heller, ISU assistant crop sciences professor, led a tour of three cover crop systems that looked at seeding, management and benefits.

The tour included details of a multi-institutional research effort to develop pennycress as a cover crop and also a profitable oil seed crop.

Pennycress not only provides the same benefits of other cover crops such as reducing soil erosion and fertilizer runoff, weed suppression, pest suppression and increased carbon sequestration, but also provides nectar and pollen resources for pollinators and groundcover habitat for beneficial insects.

ISU, Western Illinois University, University of Minnesota, Ohio State University, University of Wisconsin-Platteville and the St. Louis-based crop development company CoverCress were awarded a grant from the U.S. Department of Agriculture through the Integrated Pennycress Research Enabling Farm and Energy Resilience project.

Win Phippen, Western Illinois University professor of plant breeding and genetics, serves as project director for IPREFER, a five-year $10 million USDA National Institute of Food and Agriculture project.

John Sedbrook, ISU professor of genetics, and Bill Perry, ISU professor of aquatic ecology, are among the co-principal investigators for the project.

In addition, the U.S. Department of Energy awarded a $13 million grant to a nationwide project led by ISU. Sedbrook leads the project that’s aimed to genetically strengthen a plant for use in sustainable energy efforts. ISU received $1.8 million in DOE funding for direct use at the university.

The researchers are attempting to transform the plant into a commercially grown cover crop that would be a boon to farmers and the environment. The harvested plant would be processed into biofuel, jet fuel, animal feed and other products.

Pennycress seed was broadcast with a hand seeder into standing soybeans in September and more was seeded in February. Fifty pounds of nitrogen also was applied on the plot to study its affects on the soil pore water nutrients.

Annual Rye

ISU’s annual rye and radish plots were planted following the silage corn harvest on Sept. 16 and an annual rye and radish mix was planted Oct. 10 after the grain corn harvest.

“Planting date is one of the big things we’ve seen with cover crops. The more timely they are planted the more biomass that develops quicker,” Heller said.

“All of the annual rye was drilled. We did try and aerial application with a drone of annual rye and radish on the other side of the farm. Unfortunately after we applied it we got a one-tenth inch rain and then no rain for about 40 days after that and so we didn’t see a great establishment.”

Although the name suggests that annual rye is an annual, it was green during the spring tour.

“We get fall growth and it didn’t die over the winter and came back. Despite the name, every year that we’ve grown it’s come back in the spring. So, part of managing cover crops is also part of the story. You’re going to have to switch from this to a cash crop at some point. For our management, we’re going to spray it with chemical. Last year we sprayed it with Roundup and had a rain too close to that application and it didn’t die with Roundup. Other practices have been done, but no winter-kill in this case,” Heller continued.

The above-ground benefits of a good cover crop stand are evident — weed suppression. Cover crops also create pores in the ground, add carbon to the soil and keeps nutrients in the field for the next cash crop.

“If you look in the denser cover crop stands you don’t see a surplus of weeds, whereas as we walk along this field that was kept empty you’ll see that despite fall tillage we still have a pretty solid cover of different weeds,” Heller said.

Cereal Rye

The cereal rye was planted with a drill into no-till on Nov. 7 after the grain corn was harvested.

“The cereal rye is lagging a little behind (compared to the annual rye plots) because it didn’t get any of that fall growth. We got kind of a warm December rain and it germinated and made some plant material before the winter and has started to grow a little bit this spring, but not nearly in the explosive phase that is seen with the earlier planted cover crop,” Heller said.

“Cereal rye will respond to just about every condition we throw at it. Early planting puts on a lot of biomass in the fall which is more ideal and what I would want for a cover crop, but even it you plant it late it will still grow, just don’t expect the later planted to just magically produce a lot of biomass by April 15.

“In the past we’ve used cereal rye for a number of different purposes. Almost all of our corn acres get cereal rye put on them because we like how it covers the ground, starts to break up the corn stalks, holds the nutrients in and suppresses the weeds in the following soybean crop. A lot of farmers will use cereal rye as forage, either letting their cattle graze on it or chopping it before planting the following crop.”

The plan this year is to terminate the cereal rye with a chemical application and then plant soybeans behind it.

“The two options we have to deal with the cereal rye are we can kill it and then plant or we can plant and then kill it. I’ve seen a lot of luck with guys planting into it green. The plant tissue seems to be cut more easily with the row units when it’s green rather than if you were to kill it and let it go brown first,” Heller noted.

“Sometimes the planter doesn’t like to go through it and kind of pinch it. It depends on what stage the cereal rye is in when you kill it, too. Smaller plants will be easier to get through alive or dead than the bigger ones.

“I’ve seen guys plant into 4-foot tall cereal rye. It depends on how your planter is set up and how you deal with that. I don’t have one great answer as far as planting green or killing it first because there are a bunch of variables.”

The cost of using cereal rye is about $10 to $15 per acre for seed and $10 per acre for planting.

“Nobody is really paying us to grow cereal rye. We had to buy the seeds and we’re going to kill it before it produces anything that can be harvested. So, for your average farmers that’s not a direct monetary return on your investment,” Heller said.

“I did not include a termination cost in the estimate. We would have put a burndown chemical on our bean ground anyway, so I don’t feel like that necessarily an added cost. That’s one of the cheaper cover crops.

“There’s a learning curve. You’re not going to always succeed the first time you try something new. We tried aerial seeding this year and for whatever reason it just didn’t work out as well as we had hoped.”