Cash Crop Yield Bumps From Using Cover Crops


Sustainability in Action: Illinois farmer is starting to see yield bumps where he has used cover crops

Kirk Kimble grew up on a farm, and has been a full-time farmer since 1993. He plans on farming for many more years, so sustainability is more than just a buzzword for him.

Thoughts on Sustainability

“To me, farm sustainability means using the fewest resources for the most return on investment.”

 – Kirk Kimble
Chillicothe, Illinois

“I try to be out at the front edge on the challenges we’re facing in agriculture,” he says.

On-Farm Management Practices

Kimble has been no-tilling soybeans since 1996 and corn since 2006. He recalls starting with a few test fields to get the hang of it, then adopting no-till methods completely.

He also just completed his fifth season using cover crops. For the past two years, he has covered all of his 1,000-plus acres with them. He says the biggest challenge when starting out is figuring out how to manage them.

When he began, he experimented with seeding methods and timelines, along with the mix of seeds – or “cocktail” – he chose.

“The more you do, the more confident you become,” says Kimble.

He adds that yields are starting to improve on the fields where he has used cover crops the longest.

“As far as yields, the first couple years there wasn’t much of a change,” he says. “But we are starting to see yield bumps this year.”

He worked three fields this year that he had just purchased, none of which had ever seen cover crops, which makes for easy comparisons. He says the fields on which he’s planted cover crops for the past five years are outyielding the new fields by an average of 10 bushels of soybeans per acre.

Cover Crops Process and Benefits

Kimble has found a specific process for cover crops following corn and before soybeans. It must be working, because those fields yielded him an average of 65 bushels per acre on his beans last year.

“I like to interseed cover crops into corn,” he says. “We put 50 pounds of cereal rye, two pounds of tillage radish and two pounds of rapeseed onto each acre.”

Interseeding cover crops into a stand of corn, as opposed to waiting until after harvest to sow, comes with advantages. Early frosts, which can prevent germination and leaf development, are less of a concern, and tubers like tillage radishes have sufficient time to develop before the first frost kills them. Once they die, they begin decomposing in the soil, distributing their nutrients in a form that will be ready for the following summer’s cash crop.

Once spring arrives, Kimble uses a combination of herbicides to burn down the remaining cover, which he can then no-till soybeans right into.

In addition to the yield benefits mentioned earlier, Kimble was able to reduce nitrogen inputs by 10 percent on this year’s corn crop, with no adverse yield impact.

“I also notice the overall consistency on my cover crop farms,” he says. “It seems to be bringing less variability from field to field and season to season.”

Trusted Sources of Information

Kimble has partnered for the past year with the Soil Health Institute to share information other farmers. He also learns a lot from other farmers and from national conservation organizations, like the National Resources Conservation Service (NRCS).

He learned a great deal from NRCS when he first started using cover crops. He was so happy with the response from his fields that he quickly began planting far more cover crops than were required to participate in the NRCS cost-share program.

Advice to Other Farmers

Kimble has general and specific advice for other farmers who might be interested in adopting new practices or learning more.

“In general, try to go to some of the field days on farms near you,” he says.

He also says it’s very important to find a mentor – someone who can help with equipment, seed and planning advice.

“If you’re trying cover crops, start by picking a field that has been a trouble spot. If you’re trying no-till, pick a spot with good drainage.”