October 6, 2020

Going All In With Cover Crops, Reduced Tillage

 |  By: Jim Dickrell

Six years ago, Tom and Lorene Mueller and their partners Kathy Trimner, her son David, and Andy Miller, decided they need to be part of solving water quality issues in the Eau Pleine Watershed which serves as the headwaters to the Wisconsin River.

For decades, the Eau Pleine Watershed has experienced phosphorus loading, algae blooms, sediment runoff and occasional fish kills. Manure and nutrient runoff from farm fields have been identified as contributing factors.

Miltrim Farms operates 5,000 acres of corn, hay and small grains to feed 3,000 cows. As one of the larger farms in the area, their farming practices were being both watched and scrutinized by both farming and urban neighbors. The farm is just 30 minutes north of Marshfield, famous for its medical clinic.

Most of Miltrim Farms’ acreage is in Marathon County, which produces the most corn silage in the nation. Conventional practices, which have evolved over the past few decades, means corn silage often leaves ground bare between the rows. Suppressing weeds is thought to maximize yields, but also leaves fields prone to nutrient runoff and erosion.

Much of the ground in Marathon County is silt-loan which overlays a poorly drained subsoil. That can make farming a nightmare in wet years, both to get corn planted in spring and harvested in fall. That, in turn, can lead to compaction and torn up fields, jeopardizing crop success in future years.

“What really pushed us toward cover crops and reduced tillage was the health of Wisconsin water,” says David Trimner, general manager of Miltrim Farms. “We absolutely enjoy using the water for recreation and fishing, and we need clean water for drinking for our families and our cattle. So we want to keep it healthy—that’s important to us.”

To do that means taking care of soil health to reduce run-off and erosion. “If we continued to do current practices, soil would be degraded and we have a high risk of erosion in some fields,” he says.

Another motivation was that large dairies are often portrayed as polluters, says Tom Mueller, president of the operation. “We want to change that perception. We can either be ahead of this or behind it. In the future, cheese plants will only buy milk from sustainable farms.”

A third reason was economics. “Over the past 15 years, our yields have gone up 20% but our cost of production has increased 50%,” Mueller says. “That wasn’t sustainable and we had to do something different.”

About half of Miltrim Farm’s acreage is in corn, with the majority of that harvested for corn silage. That fact opened the opportunity for cover crops and reduced tillage. Cover crops not only reduce runoff and erosion, they have the potential to rebuild soil structure, increase water infiltration and improve soil health.

The farm started experimenting first with cover crops because they thought the farm’s soils were too heavy for no-till. They first tried seeding cover crops after corn silage was harvested. But the farm is at about the same latitude as Green Bay, Wis., so day length in the fall shortens rapidly and cover crops don’t grow well this late in the season. The farm has now gone to interseeding cover crops shortly after corn emergence in late spring/early summer.

The cover crop is a mixture of clover, rye grass, rape seed, cowpeas and hairy vetch. Each provides its own attributes: Clover for nitrogen fixation and regrowth in spring, rye grass for soil coverage and deep roots to break up soil compaction, rape seed for insects to feed on and soil coverage, and cowpeas and hairy vetch for nitrogen fixation. Total planting rate is 15 to 18 lb/a.

Plus, the cover crops make corn silage harvest easier. “The cover crop creates a mat that carries our silage trucks much better, and it eliminates dust (which can also be a loss of soil and nutrients),” says Trimner. “We’re not tearing up the fields which makes planting with our no-till corn planter easier the following year.”

The farm also grows about 200 acres of oats for feed and bedding. When that is harvested in mid-summer, winter rye is immediately planted to provide a cover crop. “Our goal with cover crops is to have growing plants on every acre every day of the year,” says Trimner. While these crops might go dormant in winter, they immediately green up as winter ends to prevent spring runoff.

The cover crops provide the soil with nutrients and promote soil health, and the hope is the farm will be able to reduce the amount of commercial fertilizer that is needed.

The farm has already reduced the rate per acre of manure application. Using drag hoses and low disturbance tool bars on manure tankers, the farm has reduced manure application to 10,000 gal/a on corn. They have reduced manure application on hay ground to 7,000 gal/a, using a dribble barn that places manure onto the soil while the crop growing. Using this technique reduces the amount of liquid manure that splashes on plants and reduces odor.

Driven by data from yield monitoring and GPS mapping, Miltrim Farms has also taken land out of production that wasn’t covering input costs. “We found we could actually take land out of production and be more profitable,” says Tom. “We put 32 acres of unproductive land into permanent habitat…. We need only 6 or 7 acres of good ground to make up the yield loss.”

A year ago, Miltrim Farms also installed 18 robotic milkers, and is now milking 1,100 cows with the machines. (It milks about 1,400 cows in a herringbone parlor.) The robotic milkers has reduced water use for those cows by about 25% through reduced water use by the milking system and in holding areas. The plan is to add another 12 robotic milkers in the future, further reducing water use.

In addition to all of this, Miltrim Farms began working with the Alliance for Water Stewardship (AWS) to obtain certification for its water conservation efforts several years ago. AWS in an international organization that works with companies of all sizes to conserve and responsibly use water resources. Last year, Miltrim Farms became the first farm in North America to receive AWS Core Certification for its water use practices.

Though an arduous process, Trimner says he and his partners chose to seek AWS certification because they want to hold themselves accountable, learn new practices and push themselves to do better. The AWS certification is third-party audited which also gives the farm more credibility with their community, lenders, vendors and milk buyer.

Plus, it shows neighboring farms what can be done. To that end, Miltrim Farms has joined the Eau Pleine Partnership for Integrated Conservation (EPPIC). This group includes farmers, farm organizations, conservationists, wildlife groups and local and state government agencies. The goal is to provide information and resources to other water users to improve stewardship.

That effort in community out-reach seems to be working. To date. EPPIC participants have converted about 15,000 acres of conventionally tilled ground to no-till, planted 9,000 acres of cover crops and switched 1,500 acres of pasture to managed grazing.  

The point is to continue to learn what works best on local farms and share that knowledge. “There has been more and more interest in our area about cover crops and reduced tillage,” says Trimner. “We want to make these practices widespread.”

For more on Miltrim Farms Alliance For Water Stewardship certification, click here.



Sidebar: Feed Quality Improves

With Land Conservation


It might not be intuitive at first, but corn silage digestibility improves with soil conservation practices that involve no-till farming and cover crops.

“After 5 years of no-till plus cover crops, corn silage digestibility increased by 2-6% in 2018 and 2019 in comparison to silage grown in a conventional tillage system without cover crops,” says Jason Cavadini, an agronomist with the University of Wisconsin Marshfield Experiment Station in northcentral Wisconsin.

“In the last two years of our trials, we started detecting increased digestibility in feed quality with interseeded crops,” he says. “And we were sure we were not getting mixed feeds from the interseeded crops in our corn silage based on how we were harvesting the silage.”

In the first four years, Cavadinia saw soil health improve but did not detect any yield differences. In the next two years, he saw forage quality increase, which he attributes to soil health and improved biology.

“The difference in feed quality came from the corn silage itself that we were measuring in our plots,” he says. “Our running theory, with consecutive years of minimum tillage and green cover crops, is that we are getting levels of biological activity in the soils we haven’t seen in a long time and that is being reflected in our crop quality.”

No-till and cover crops have not had an effect on crop yields. In terms of production costs, Cavadini says most farms try to limit planting and seed costs to $30/a. This can be recouped by saving two tillage passes. It can be more than recouped if farmers are taking a cutting of cover-crop forage.

The first benefit farmers see with reduced tillage and cover crops, however, is that fields can carry heavier traffic. In years with wet autumns, that can prove a huge benefit to getting crops harvested. It also reduces, and often eliminates, the need for spring tillage ahead of planting.