Cover Crop Code

17 Aug 2015

By Todd Neeley
DTN Staff Reporter

NORTHFIELD, Minnesota (DTN) -- The southeast Minnesota rains came in June -- as they almost always do at Far-Gaze Farms.

It was especially important to farmer Bruce Peterson and his family operation, as the farm is one of several that attempt to crack the cover crop code.

The ground is frozen for nearly half the year, so establishing a cover crop in between rows of tall corn is a tall order.

Those June rains provide opportunity.

Peterson, whose family farms about 6,000 acres with about two-thirds planted to corn and the remaining one-third to soybeans, said the varied soil quality on his land makes it challenging to adjust to nutrient needs. Peterson said his farm converted to less tillage in the 1960s when there were wet spots on high ground. The bottom ground had a different subsoil makeup.

"The question is: How do you define and deal with soil quality at the farm level?" he said. "We've got real variable soils."

As part of the newly formed Rice Soil Health Group in Rice County, the Petersons took part in an inter-seeding demonstration project on display last week as part of the Conservation Technology Information Center's Conservation in Action Tour, which made stops at five different farms working on sustainability.

The Peterson farm inter-seeded a variety of cover crops including white clover, annual ryegrass and radish in June, and here in the middle of August there is a sparse cover crop growth between rows and underneath a 7-foot canopy.

The Minnesota winter makes it nearly impossible to plant cover crops in the fall following harvest as producers in other regions are able to do.

"The growing season ends in October with harvest around the end of November," said Tom Coffman, district conservationist with USDA's Natural Resources Conservation Service.

"Inter-seeding into June we can include multiple species. By seeding in June it opens a window. We end up with about five months of roots. We get 10 to 12 rain events in June, so throwing seed on the surface has been effective. Seeding that time of year on top is not an issue this year."

Although the rains allowed establishment of cover crops in the demonstration project, as the growing season progresses, those crops face a number of challenges to getting well-established to the point of providing long-term water-quality benefits.

Finding cover crops that can survive winter will be a key.

SOIL PROBE

During the tour, NRCS did a soil probe about 2 feet down in corn fields where cover crops were planted. In addition to the canopy blocking out the sun, corn's high nitrogen uptake has started to sap energy from the cover crops.

So chances are those plants will begin to lose steam as fall approaches, although that may not be the case for all fields depending on soil type. One probe in the Peterson field found nitrate levels of just 5 parts per million. Coffman said the cover may not be there in two weeks.

"These guys are busy in the fall," Coffman said. "Last year in November it froze really hard. If we could seed in June with a sidedress, it stepped up fine for us."

COVER CROP SURVEY

A 2015 cover crop survey conducted by the CTIC, for a third consecutive year, found a "statistically significant increase" in corn and soybean yields following cover crops.

The survey of more than 1,200 farmers across the country found corn yields increased 3.7 bushels per acre, or about 2 percentage points, following the use of cover crops; soybean yields increased by an average of 2.2 bushels per acre, or by about 4 percentage points.

Cereal grains and grasses were the most popular cover crops planted, planted by 84% of the 1,287 cover crop users who responded to the survey.

Rice County farmer Jim Purfeerst took part in a cover crop study in 2014. At the time, he inter-seeded 10 pounds of ryegrass, four pounds of radish and four pounds of white clover per acre with a John Deere spreader on June 26, 2014. He used urea to carry and spread seed 60 feet.

Purfeerst had solid ryegrass growth by July 22, and by Sept. 30 it stood about 10 inches high in between his corn rows.

So far this year, the cover crop cost per acre on Purfeerst's farm ranged from about $30 to $37 an acre in the NRCS demonstration.

The farm has yet to see problems with pests, excess residue or yield losses, and the cover crop is insured as long as it is planted with an insured crop such as corn or soybeans, he said.

"Last year was a super year for cover crops," he said. "We didn't have any yield drags. I think the big goal here is economics, getting the cost down so we can do it. Right now about $22 an acre is doable. One of the big benefits is the snow spring melt off. It worked really well for us."

Read the 2015 CTIC cover crop survey here, http://tinyurl.com/…

Todd Neeley can be reached at [email protected]

Follow him on Twitter @toddneeleyDTN

(CZ/BAS)