Cover crop club keeps learning

Trying something new and innovative is always easier when you can learn from someone else’s experience. For a small group of innovative farmers experimenting with cover crops in Pottawattamie County in western Iowa, that someone else is Pete Hobson.

Hobson, a 20-year no-till veteran, says he turned to cover crops as a tool to build more organic matter after test results showed his soils’ organic matter had plateaued. “Ideally, I would like to increase organic matter 1% every 10 years. I’m planting ryegrass as a cover crop because it will root much deeper than wheat or cereal rye, and is a better organic matter builder,” he says.

Hobson aerial-seeded rye at the end of August at a rate of 25 pounds per acre. “I was surprised, with how little rain we had in September, that it even germinated,” he says. Looking at a mat of green under his cornstalk residue in fall, he asked, “If we can do this well with cover crops in a dry year, how well can we do in a normal year?”

Key Points

More farmers are taking a look at fall-planted cover crops to stop erosion.

Group of western Iowa neighbors are learning to manage the practice together.

Among other benefits, cover crops help improve soil quality in the long term.


With the smaller, lighter-weight ryegrass seed, the biggest issue with aerial seeding is getting an even distribution on the field. “Mixing in some cereal rye or going with a helicopter instead of an airplane to do the seeding might be the way to go, so you can get closer to the field and get a better pattern,” he says.

Share experience, information

It’s Hobson’s willingness to adapt and experiment that makes him such a cover crop resource for local farmers, like Lowell Forristall and Jim Andersen. “Pete is a wealth of information. He’s even better than going to the Internet when it comes to learning about cover crops in this area,” says Forristall. “Pete makes it work, and he also has landowners who will work with him and are willing to be progressive.”

Forristall, a neighbor and fellow East Pottawattamie Soil and Water Conservation District commissioner, got serious about cover crops in 2011 and is trying to lead by example. “If I’m not using some of these conservation practices on my land that I control, how can I say someone else should use a practice or at least should consider it?” he asks.

This year Forristall has 37 acres of ryegrass in his operation near Macedonia. His cover crops are part of his five-year Conservation Stewardship Program contract. CSP is a voluntary farm bill program administered by USDA’s Natural Resources Conservation Service. Under CSP, participants are paid for conservation performance; the higher the farming operation’s performance, the higher the payment.

He drilled ryegrass in mid-October at a rate of 56 pounds per acre, choosing fields that needed more organic matter and were harvested by mid-October.

Radishes are a cover crop

His cover crop experiment also includes 15 acres of radishes planted in areas enrolled in his Environmental Quality Incentives Program summer construction contract. He built 6,000 feet of terraces under the initiative, which requires a cover crop to protect unplanted soil from erosion. He planted the radishes with a 15-foot no-till drill along with an oat companion crop.

“The biggest challenge with radishes is the planting time. They need to be planted by mid-August,” says Forristall. “If you don’t have bare ground, like I did because of the terrace construction, the radish seed would have to be aerial-seeded.” His seed vendor from Nebraska advised an oat companion crop for weed suppression. His seeding rates were 3 pounds per acre for the radishes and 36 pounds for the oats.

Forristall, who is in partnership with his son Brad and custom-farms with a group of other farmers, is pleased with what he’s seen so far with radishes as a cover crop. “If you can get the root to grow out, then you make a natural water passage in the soil that’s more effective than my ripping,” he says, pulling a radish out of the soil. The radish had at least an 8-inch-long, slender root growing from the bottom of a 6-inch-long, 2-inch-diameter radish. These roots go deep and break up soil compaction.

He also hopes to build more organic matter in his soil through cover crop management. “I’ve heard for every 1% increase in organic matter, you add 30 pounds of nitrogen in the soil. Building more organic matter means more microorganisms in the soil and increasing the microbial activity. We’re building a better neighborhood for the beneficial soil microbes,” he explains.

A third benefit is the “free” nitrogen that cover crops provide. “This is a learning curve for me. I didn’t realize that the nitrogen taken up by the cover crop, if you don’t harvest it, is still all there in the crop at the end,” he says. Thus, if he didn’t grow a cover crop, some of the nitrogen he might have lost from the field after harvest and during the winter is tied up in the growing cover crop, which acts like a nitrogen savings account for crops that follow.

Savings account for nitrogen

Jim Andersen first got the idea to try cover crops at an Integrated Crop Management conference at Iowa State University. He likes the benefit of cover crops saving soil and nitrogen, keeping these resources in the field and out of creeks and rivers. “I looked at the data and came home from ISU and told Harold Hoffmann [his tenant] we are going to try this,” says Andersen.

Andersen, a retired agronomist for DeKalb, lives in Council Bluffs but owns 160 acres his father used to farm near Hancock. Besides ISU Extension specialists, Andersen relies on Hobson for advice. “Pete Hobson is my mentor,” he says.

Andersen’s main motivator for trying cover crops is erosion control. He’s concerned about rills and small gullies that have been forming on his hillsides. Andersen drilled 150 acres of ryegrass after soybean harvest last fall using a 15-foot drill. He estimates it cost $15 per acre for the seed and drill rental.

All three of these farmers don’t anticipate any changes in their spring management of their cover crops, with the exception of adding Roundup to their preemergence herbicide treatment. “I won’t have to change my workload, just my chemicals,” says Forristall. “Man-hours are the key. I have to avoid adding more hours. The only extra time it takes for growing a cover crop is drilling of the rye.”

Greiner writes for NRCS in Iowa.

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GOOD GROWTH:
District conservationist Greg Mathis (left) and farmer Lowell Forristall discuss the healthy growth of cover crops they planted in August. Radish is one of several species they’re using to provide cover for soil in fall and winter.

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COVERS WORK: Pete Hobson, who farms in eastern Pottawattamie County, mentors several farmers in his neighborhood on managing cover crops. “For very good reasons, more farmers are planting cover crops,” he notes.

This article published in the February, 2012 edition of WALLACES FARMER.

All rights reserved. Copyright Farm Progress Cos. 2012.