Trials find success in corn, cover crops

MARION, Ill. — Planting soybeans into a cover crop such as cereal rye is a common practice, but cover crops ahead of corn is a different animal.

“There’s been a lot of success stories with planting soybeans into cereal rye at various stages. But it seems like there’s a need for more information and more demonstrations on effective management ahead of corn because of nitrogen management and some of the residue management issues,” said John Pike.

Pike, an operator of Pike Ag LLC, located in Marion, is a consultant and researcher specializing in nutrient management, cover crops and water quality. He has worked with cover crops for nine years and gave his in-field findings in an ILSoyAdvisor video.

He said it’s important to have a strategy and plan well in advance because cover crops and their management need to be suited to the location, the crop rotation and the field environment.

Cover Plan

Pike planted corn this year into a cover crop mix of cereal rye, annual rye grass, crimson clover and hairy vetch.

During a stretch of good weather in early April he applied a selective grass herbicide that killed the grasses and left the legumes. All of this began with a plan in place the previous year.

“My plan started before I planted the soybean crop last year. I had a relatively early variety. It wasn’t super early for the region, but something that would be on the earlier side of our maturities. I planted that soybean early to give me an early harvest window, and that allowed for the cover crop to be planted a little bit earlier than what we might have with a later soybean variety,” he said.

The cover crop mix was planted the first of October last year after the soybean harvest.

“I got the cover crop planted in time and there was plenty of warmth and day length and growing degrees to get that cover crop established and out of the ground so it was ready to go into the winter and had good winter survival,” Pike said.

The cover crop faced cold temperatures in the single digits for three to four days last winter, which caused some loss in the crop, but it recovered and grew into the spring.

Pike said had the cover crop seeding been two to three weeks later in the fall there would not have been as much growth of the hairy vetch or crimson clover species. The month of April brought termination of the cereal rye and annual rye grass.

Termination

“The idea of managing this cover crop in the early spring was to terminate the grasses out of the mix and just leave legumes to grow,” Pike said.

Due to a wet spring in southern Illinois, Pike wasn’t able to get the corn planted as timely as he would have liked, but the cover crop legumes continued to grow with the hairy vetch being in full bloom, maximizing the legumes’ nitrogen contribution the corn crop that will follow.

When planning for a cover crop program, Pike said it’s important to think through one’s whole system strategy as issues have risen up depending on what cover crop mix that the cash crop is being planted into — specifically in this case, planting corn into cereal rye and the nitrogen concerns it brings.

“One of the big problems we get in planting corn into cereal rye is the carbon-to-nitrogen ratio is out of balance. We have all of the nitrogen taken up into the cereal rye plant and it’s really not available to the corn crop to follow,” he said.

“In my field where I planted the mix that included cereal rye, we took the cereal rye out when it was about 6 inches tall with a selective grass herbicide and to just leave the legume growing.

“So, we have the planting environment that would be roughly the same as if we were planting into a solid-seeded legume, but we’ve taken the cereal rye out of picture as far as dealing with the residue to plant into from a biomass standpoint, and we’ve also sidestepped a lot of the problems with the nitrogen tie-up.

“Plus, we’ve got the living root in the soil with the legume plants that are helping to dry out the wet soil and they’re adding another source of nitrogen that the corn crop will benefit from.”

Pike chemically terminated the legumes after the corn was planted.

“At that point all of the residue mat will fall down in between the corn rows. That will provide better temperature regulation and moisture conservation through the summer,” he said.

“We’ll get a better control of weeds or some suppression out of that, even though I will put a residual herbicide on to make sure the field stays clean. We’ll see some suppression from that residue mat. We’ll see better moisture conservation and also maintain cooler temperatures through the growing season.”

Temperature

When comparing a no-till cover crop field with a conventionally-tilled field in the summer, Pike found the soil temperature is much lower in the cover crop field.

“So, while it can be a challenge to manage the cover crop in the spring and to get the corn crop established, once we do that, the rest of the growing season is generally a more favorable environment for the corn to develop in because we’ve got temperature moderation and a little bit better moisture conservation, especially in southern Illinois. But these are things that could be benefit in other soil types in other parts of the state,” he said.

“Depending on where you’re at, your management considerations are going to need to be altered just a little bit to make it work the best.

“There’s no silver bullet solution to anything, so I think we need to take into account all the information that we can get and the suggestions from others. We need to make sure our plan is regionalized to our location, our farm and our individual fields especially.”

After the corn is harvested in the fall, Pike plans to drill another diverse mix of cover crops into the field. He intends to plant an early-maturing soybean crop next spring.

Nine years into an intensive cover crop management program, Pike said he has seen big improvements to his farm operation, soil health and nutrient management.