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Field day focuses on cover crops
In rural Ferryville
swede fld day

Forty local farmers attended a cover crop field day held at Swede Knutson’s farm in rural Ferryville on Friday, April 7.

Knutson has participated in Crawford County’s aerial seeding program since its inception in fall of 2014. He had 383 acres enrolled in 2016.

Those gathered for the event last Friday spent a large part of the day digging in the soil, while considering various cover-cropping and tillage results. The farmers seemed to agree that cover cropping saved them money, and increased the soil’s water retention and health. Many cited the benefits of increased yields and erosion control.

The field day was kicked off by Ben Wojahn, Vernon County Assistant Conservationist, with some cover crop humor.

“Protecting your soil with cover crops is like your relationship with your wife. If you don’t treat her well, she’ll run off,” Wojahn quipped.

Cover crop results

Participants at the field day were asked to share the reasons they use cover crops on their fields.

One participant said that he uses cover crops on his wheat fields to get some cover, enrich the soil and prevent erosion. Others said they did it for weed control, to help prevent soil compaction and for additional grazing.

When asked if cover cropping was saving them money or costing them money, almost all participants agreed that it was saving them money. One participant seemed to indicate that for him it was a little of both.

To prepare for the field day, Knutson dug trenches in four of his fields with cover crops. Each location had a different mix of cover crops planted, using either aerial or machine-planting, and different tilling approaches.

In the first field, Knutson had used his Airmax to seed winter rye with a potash mix, followed by vertical tilling. In the second field, he did the same but without vertical tilling.

“I tried tilling to incorporate the seed,” Knutson explained, “but I can’t say as it really helped.”

Roots go deep

NRCS Soil Scientist Kevin Traastad climbed into each pit to talk about what he saw, explain various soil characteristics, and point out the post-it-notes placed along the sides of the trenches indicating depth of soil compaction and of the old till line, depth of the roots of the cover crops, worm tunnels and more.

“You can see where the roots in this first trench have grown to 32 inches of depth,” Traastad said. “For conservation benefits, you need at least four inches of above ground growth in the fall, and 12 inches below.”

In the field across the road, where vertical tilling was not used, the roots had grown to 34 inches of depth and there were worm tunnels in the soil at depth.

Traastad educated participants about how cover crops and increased soil organic matter can help to increase water retention.

“For every one percent increase in soil organic matter in an acre, the soil will hold an additional 20,000 gallons of water,” Traastad said. “This is significant because one inch of rain equals 27,154 gallons of water.”

The third field had been aerial seeded with a mix containing clover and radish, preceded by wheat. The roots of the radishes had grown to about 36 inches of depth, and the clover had gotten big enough that the landowner was optimistic he would receive a nitrogen credit.

 “It’s not only organic matter that increases in the soil with cover crops,” Crawford County UW-Extension Agent Vance Haugen explained. “There’s also the biological composition of the soil which changes the amount of phosphorous and potassium and increases uptake by the plants.”

Traastad expanded on Haugen’s point, explaining that because of the history of manure spreading on the fields, there was already ample phosphorous present in the soil.

“Increasing the microbiology of the soil is essential in allowing plants to take up the phosphorous and other nutrients present or applied in the field,” Traastad told the group.

Good field edge coverage

In the fourth field, a mix of rye and oats had been planted along with potash. It was a small field, surrounded by trees, which are challenging for pilots in the aerial planting process.

Admiring the thoroughness of the planting, right up to the edge of the field, some participants commented that “it was a darn good job of planting from an airplane, with good field edge effect.”

Robbie Lindquist, with Ag-Tech Air, the company Crawford County contracts with for the aerial seeding program, explained how their talented pilots achieved such good results.

“Our pilots use very sophisticated GPS software to show them where the fields are,” Lindquist said. “All the little oddly shaped fields in this part of Wisconsin, combined with the hilly terrain present challenges. When they approach these kind of fields, they start the drop as they reach the edge, to ensure good coverage throughout the field.”

Aerial seeding program

In 2016, it was the third year that Crawford County offered the aerial seeding program to county farmers. The program is coordinated by the Crawford County Land Conservation Department led by David Troester, the county conservationist.

In year one of the program, the county had 1,700 acres enrolled, in 2015 it was 2,300 acres, and in 2016, 3,200 acres were enrolled.

There is still time for Crawford County growers to apply for EQIP funding for cover cropping under a pollinator initiative. The application deadline is June 2.

“We offer two options for cover crops. The first is a ‘winter kill’ option, which is a mix of spring barley, oats and forage radishes,” Troester explained. “The second is a mix of oats, which will grow strongly in the fall and die, and winter cereal rye, which will come back in the spring.”

Vernon County does not currently offer an aerial cover crop seeding program. Initiation of a program would be up to the county’s NRCS program, according to county conservationist Ben Wojahn.

The planes take off from the Boscobel Airport. Ag-Tech Air uses the biggest agricultural airplanes available, which can seed up to 50 acres per load, depending on the seed density. The spreading pattern is approximately 60-65 feet.

“We can provide the grower with an auto-text-message for the start and completion of the planting, and can even offer a printed coverage map,” Ag-Tech Air’s Lindquist noted.


Having a well-thought-out spring termination plan is an essential part of using cover crops.

Spring day and night temperatures are critical to a cover crop termination plan.

“You want to terminate when temperatures reach 55-degrees during the day and 45-degrees at night,” explained Dan Smith, a UW-Extension Nutrient and Pest Management Specialist with the UW-Arlington Research Station.

Smith urged growers employing cover crops to pay close attention to temperatures and be sure to make a termination plan up front.

“They won’t become weeds if you have a plan,” Smith said. “The seeds can come very quickly in the spring, so vigilance and a proactive approach are essential.”

Smith went on to discuss the pros and cons of various cover crop options, and choices for termination such as the roller crimper, herbicides, mowing and tilling.

There was some discussion of alleopathy, which is the chemical inhibition of one plant by another, due to the release into the environment of substances acting as germination or growth inhibitors. Winter rye is a cover crop that particularly raised alleopathy questions.

“With rye, it is more of a nitrogen issue than an alleopathy issue,” Smith explained. “Rye releases more nitrogen, and at a different rate than corn needs.”

Roller crimper

The roller crimper is a front-mounted cover-crop roller that knocks down a weed-suppressing mat that can be planted through all in one quick pass.

Steve Hornby, an organic producer from Liberty Pole, attended the field day and talked about using the roller crimper on his farm.

“I recommend the roller crimper because I don’t have any weeds, and I am getting bigger yields,” Hornby said.

Chaseburg Manufacturing in Coon Valley is currently manufacturing roller crimpers in the area. The company can be reached at 608-452-3040.

According to Wojahn, “they will be available for sale at a cost not to exceed $5,300.”

More field days planned

The second of three field days is planned for Saturday, May 20, 10 a.m. to 2 p.m. Participants should gather at the Mt. Sterling Park Shelter at the corner of State Highway 27 and 171. Participating farmers can RSVP by calling Sarah at Vernon County LWCD at 608-637-5480.

The event will be hosted on the farms of Jay Aspenson, rural Eastman, and Eric Hammel, rural Seneca.

At the event, national soil health expert Jay Fuhrer will educate participants about how cover crops can improve soils. There will be a rainfall simulator showing how cover crops protect the soil, and different termination methods such as the roller crimper, herbicides and tillage will be demonstrated.

The events are planned by the Crawford and Vernon County Land Conservation Department’s (LWCD) and Ted Bay of the UW-Extension in Grant County, along with USDA Natural Resources Conservation Service (NRCS), and the National Wildlife Federation.