Cover crops take over

ST. PAUL, Minn. – Cover crops are gaining the full attention of the agriculture industry, from seed companies to crop advisors to processors. University of Minnesota graduate students channeled that attention into the focus for their 2016...

A field in Iowa planted to cover-crop greens up in the early March warmth.

ST. PAUL — Cover crops are gaining the full attention of the agriculture industry.

University of Minnesota graduate students channeled that attention into the focus for their 2016 Production Agriculture Symposium on March 22 at the university's St. Paul campus.

Panelist Stephanie McClaine, a district conservationist with the Natural Resources Conservation Service based in Worthington, said in her 13 years with NRCS, "Never have I seen one entire topic take ahold of the entire agriculture industry as cover crops have."

The student-organized and -led event featured speakers from across the Upper Midwest who tackled real-world concerns about how to best manage covers.

BMPs — An Iowa perspective


Sarah Carlson, Midwest cover crop research coordinator for Practical Farmers of Iowa, said cover crop reality sometimes doesn't match up with expectations. She pointed to huge tillage radishes as an expectation while also showing a picture of the skinny, couple-inch-long radishes that actually grew on one of PFI's participating farms. Through randomized replicated research plots on 63 farms across Iowa, PFI is trying to figure out what practices will get results with cover crops and other management practices.

Cover crop benefits PFI has observed are far-reaching but boil down to helping manage soil water, Carlson said. PFI research shows cover crops make a bigger difference for holding nitrogen on the land than switching from fall to spring nitrogen application, with a 31 percent improvement in holding capacity for rye covers, 28 percent improvement for oat covers and only 6 percent improvement when timing changed. Covers help build soil carbon and can help with weed control.

PFI noticed no difference in cash crop yield, whether covers were terminated early or late. Carlson speculated there could be potential savings by choosing late termination and eliminating a field pass.

Sometimes, fields can have too much residue. If cover crops are aerially seeded into these conditions, they have a harder time getting established, Carlson said. Drilling covers in high-residue fields would grant a higher likelihood of success.

Allelopathy in corn crops following a rye cover have been a concern. PFI's experiments show corn yield tends to drop the first year or two after adding a rye cover crop to the rotation. However, after a couple years, as producers learned how to best manage rye, no yield drag was seen on rye/corn fields. Soybean yield wasn't affected negatively by previous rye covers and even showed yield increases over time, Carlson said.

Other findings from PFI shows the need for good planter set-up and a need for separation between cover crop burndown and nitrogen application in spring.

Expert panel

Several experienced individuals, including McClaine, shared their ins and outs with cover crops during a panel discussion. Carmen Fernholz farms 450 acres organically near Madison, Minn., underseeding cover crops into small grains. Jerry Ackermann put all 1,200 acres of his Lakefield farm into cover crops for the first time in 2015 after years of experimentation. Jim Webster is a production agronomist for DuPont Pioneer, Mark Gutierrez manages the USDA Risk Management Agency office in St. Paul.


After being blown away by learning what happens beneath the soil surface a couple years ago, McClaine changed her perspective on how she wanted to work with farmers. She now focuses on conservation planning, keeping in mind that each farmer is unique.

"We're incorporating cover crops, using fewer passes and getting better infiltration and better nutrient cycling," McClaine said.

She encourages farmers to shop when looking for cover crop seed. Look at different species, different varieties, different seed companies; all can offer different benefits and economics.

Also, while costs may be high, government programs can help.

"With conservation programs, we can facilitate for three years and provide cost-share assistance," McClaine said. "The thing is, when those three years are over, I don't want you to stop."

Fernholz started with cover crops about 20 years ago. It's difficult to put a dollar and cent sign on the benefits covers provide, but that doesn't mean they're not worth trying, Fernholz said.

"Once I started using cover crops, the economics on my farm went 180 degrees," Fernholz said.

Without conservation tillage, cover crops alone are not enough, Ackermann said. Based on Iowa State University published average custom rates, he estimates he's ahead by nearly $20 per acre by utilizing a no-till system. In addition, after years of no-till and cover crops, wet spots in fields are going away.


He grows cover crops because he doesn't want to lose any of the nitrogen, phosphorous or potash he's applied, Ackermann said.

Ackermann has never lost yield following a cover crop. Some years, yield gains are small, but he's benefited to the tune of 22 extra bushels per acre before, too.

He's consistently been yielding in the 190s for corn lately, Ackermann said. He's aiming for 200 bushels per acre. Once he gets there, he hopes he can decrease his nitrogen applications down to 120 pounds per acre.

When asked how much above-ground growth there needs to be for benefits to the soil, Ackermann replied that what's above for annual ryegrass is often three times as much below. With cereal rye, it's usually two to three times as much below.

Cover crops are a nice fit with seed corn production, Webster said.

He expects interest in cover crops to be strong this year and only get stronger.

"I hope people will try and see the economic benefits," Webster said. "Cover crops in my mind are an investment in the future."

He's noticed that people in different regions turn to cover crops for differing reasons. In Nebraska, cattle can graze on cover crops; in Michigan, they help reduce wind erosion; and in Iowa, they're chosen for nutrient cycling and soil health, Webster said.


Gutierrez sees himself as an educator. His job is to educate farmers on how crop insurance and cover crops work together, but also educate staff and policy writers as more information on cover crops comes to light.

"The economics appear to have long-term benefits," Gutierrez said. "There are a lot of formal studies taking place. We would like to see more economic exploration. More information means better decisions."

Each state can have mild differentiations in policy that can make a difference when it comes to whether a payment goes our or not. Gutierrez gave the example of double cropping not being allowed in Iowa.

"We have made as many changes as possible to allow producers flexibility," Gutierrez said.

Many producers are interested in a crop insurance discount for using cover crops. Gutierrez said more concrete data is necessary before that becomes a possibility.

"USDA's plan is to encourage cover crops with NRCS and CSP right now," Gutierrez said. "We're still in the finding best practices phase. There is more to do. We'll do our best to make changes to fit the individual."

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