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Cover Crops Make Farming Fun Again

David Brandt.

By Mary Ann Lieser

Edward Faulkner’s Plowman’s Folly was first published in 1943, on the heels of the Dust Bowl. During the 1930s, the southern Great Plains had seen millions of tons of topsoil lost, thousands of families uprooted and impoverished and hundreds of deaths from “dust pneumonia.” Faulkner’s no-till message introduced another way to plant field crops that, had it been widely adopted a few decades earlier, would have largely prevented the catastrophe that was the Dust Bowl.

 The benefits of no-till agriculture are better understood today, and no-till is just one leg of conservation agriculture’s three-legged stool of soil health, along with permanent ground covers and diverse crop rotations. Those practices build soil health rather than deplete it, and when those practices are continued over time they continue to build increased nutrition and resilience into the soils that we rely on for our very survival.

There’s no more enthusiastic proponent of no-till farming and diverse cover crops than David Brandt, who farms over 1,100 acres in Fairfield County, Ohio, in a corn-soy-small grain rotation. A Marine veteran who earned a Purple Heart in Vietnam, Brandt returned to his family’s farm over fifty years ago. He adopted no-till practices in 1971, and began using cover crops in 1978 to control erosion.

Early in his cover crop journey Brandt teamed up with agricultural researchers from the Ohio State University (OSU), and they’ve been collecting data on his farm’s soil health going back decades. For the past twenty years he’s been experimenting with more and more diverse cover crop cocktails, tracking which species bring the most soil benefits. And he’s clearly enjoying himself along the way.

“Cover crops made farming fun. It’s a challenge to solve the puzzle of how best to draw trace elements up from deep in the soil, how to attract the most beneficial insects and cut back on insecticides, how to get the best infiltration after a rain, how to make cover crops pay for themselves. I enjoy figuring all that out. Farming isn’t the drudgery some folks think it is.”

His current collaboration with OSU researchers means there’s solid data to support what Brandt’s learned through years of trial and error. His farm is, in effect, a long-term continuous no-till study site for the OSU ag department, which has demonstrated increased total microbial biomass, increased crop yields and decreased carbon loss on the land he farms.

Brandt has a passion to spread his message to other farmers, so they can learn from mistakes that he’s already made. But he also cautions that they may have to make their own mistakes, because no two pieces of land are identical. He encourages people to visit his farm, and he takes them outdoors to feel and smell the soil. He likes to see a farmer get down off the tractor and really experience what’s going on in the deeper layers. And he loves to place a photo of a shovelful of soil from when he began farming his land, next to a photo of a more recent shovelful. “We had yellow clay. Now we have eighteen inches of dark, granular topsoil. I want to take that beautiful dark soil all the way down to the bedrock. Cover crops will get us there.”

For farmers who are transitioning from conventional farming to no-till with cover crops, he believes that the biggest challenge can be to shift their thinking to a different kind of management. With the goal to “keep something of value growing as many months as possible,” Brandt sometimes harvests and replants a field the same day to keep cover on the ground. He wants to have living roots in the soil all year, but he also doesn’t want cover crops to go to seed, with the exception of sunflowers. Crimson clover, for instance, should bloom but not make seeds, for the seeds take nutrients from the soil. So timing is vital.

Brandt uses a roller crimper to terminate most of his cover crops, and termination timing can be crucial. Especially with high residue cover crops, it’s important to watch the weather, and not terminate too early. And for farmers who’ve been using herbicides, it’s important to understand how the herbicide residuals work. “Learn to manage your residue and learn the best ways to terminate your crops, and the rest usually takes care of itself.”

Nationwide, research on yield responses with cover crop cocktails has produced mixed results, but soil-health pioneers like Brandt are taking the long view. No-till farming with cover crops is a long-term investment in the soil. Yield increases may not happen for several years. Although he always keeps the big picture in mind, Brandt is ever practical about the details, whether he’s talking about purchasing fertilizer — “Why are we buying nitrogen when it’s in the air?” — or about paying for seed — “Don’t spend more on seed for cover crops than you gain in reduced fertilizer or better yield.”

Continuing no-till and cover crop practices over time seems to offer increasing benefits, as shown by Vinayak Shedekar’s work at the OSU. As part of an ongoing research project Shedekar is looking at how mature systems like the Brandt farm compare with both conventional farms and with systems that are at an earlier point in the transition to conservation agriculture. It can take up to a decade for a no-till system to be stabilized, and there haven’t been many studies that have looked at long-term effects of no-till practices because it’s not easy to find farms like Brandt’s that have incorporated these practices for more than forty years. Early measurements in Shedekar’s ongoing project have compared soil health scores for fields being farmed conventionally (which averaged 5.1) with those for fields after two years of no-till (averaging 6.1), and those for mature no-till cover crop systems (which averaged 8.1 on the soil health scale).  

Among the first cover crops Brandt used were hairy vetch and winter peas, and he still likes both of those plants. Back then he was using commercial nitrogen, but found he was able to reduce nitrogen inputs as his soil changed. Leguminous cover plants like the vetches, clovers, peas, and hemps pick out nitrogen from the atmosphere and use it to form nodules on the roots, where soil bacteria can break those nodules down, making the nitrogen available in the soil for the next crop. Brandt sometimes plants several varieties of peas in the same cover so that they nodulate in different layers of the soil, to stratify nitrogen for the corn that will follow.

These days Brandt plants custom blends of multiple species, often eight to fourteen at a time. Selecting the right species for the mixture is part of the challenge of getting to know a piece of land and discovering ways to improve it. “We’ve tried over a hundred different cover crops. Twenty we’ll never use again. Fava beans were a disaster.” But for every disaster he’s had many successes, and he’s still learning how to use specific species to meet specific goals.

He looks at priorities and chooses species accordingly. Grasses build organic matter. Early flowering plants like canola attract and support pollinators and beneficial insects. Brassicas bring up nutrients and enhance their availability, and legumes fix nitrogen. For instance, crimson clover is excellent for pulling in lots of nitrogen quickly.  But it’s also important to look at what comes before and after a cover crop. It can be difficult to establish diverse covers in a corn-bean rotation because the cover crops go in the ground later and the ta roots won’t have time to get big enough to really break up deeper soil layers. With a third of his land in small cereal grains (like rye, barley, or triticale) at any given time, those grains are harvested in July and Brandt starts his cover crops then.

He likes to plant Daikon radishes with a corn planter for deep penetration, then watch the radishes loosen and lift the soil as much as three or four inches as they grow. “When we plant corn after the radishes, the radishes with their two and a half foot tap roots have done the tillage.” Radishes have also helped the Brandt farm reduce the need for insecticides. The roots emit a sulfur smell that fumigates the soil, resulting in fewer cyst nematodes and slugs.

Sunflowers likewise have a large taproot and attract beneficial insects, as well as bring up zinc and magnesium from the subsoil, making those elements move available close to the surface. And buckwheat makes phosphorous more available to plants. “We are always looking for cover crops that will release nutrients that are tied up in the soil. Buckwheat is a good starter cover crop to use on depleted soils. It brings up phosphorous from deeper layers and jumpstarts soil restoration.” Phacelia is increasingly used as a cover, due to its thick and fibrous roots that grow quickly. “Phacelia has a tremendous root system. Pull up one full-grown plant and you can’t fit all the roots in a five-gallon bucket.”

The varying root systems of these cover crops result in less soil compaction and deeper water infiltration. Brandt believes the root systems allow for a version of infield compost tea with no extra work on his part. “I get a controlled release of nutrients every time it rains.” And when the soil retains more moisture, that soil is less prone to temperature extremes, which can cause plant stress. Brandt enjoys sharing photos that show soil thermometer readings taken on a 100-degree day. The probe in his neighbor’s soil registered 118 degrees, while his own only reached 86 degrees. Cooler soil under extreme conditions means healthier plants.

Brandt has accomplished a lot for a small-time farmer from Ohio. He currently serves as president of the Soil Health Academy, and he’s traveled to or hosted dozens of speaking engagements over the years, including a trip to Europe at the invitation of the French Minister of Agriculture to talk about how farmers can achieve carbon sequestration in the soil. His enthusiasm for the soil is tangible, and it shines through in his spontaneous comments when he looks at photographic evidence of his farm’s health. “Look at the color of that soil.” “Look at those nodules!” “Look at the cottage cheese of that soil” — this last referring to the lumpy texture that results from the formation of soil aggregates.

In the eastern US, the wood-based soils of 250 years ago would have had organic matter levels of five or six percent. Organic matter always goes down with tillage, and today a lot of farms have only one or two percent organic matter in their degraded soils. Farmers like Brandt are achieving five and six percent organic matter levels on land that’s in continuous cultivation, thus pioneering the sustainable methods future farmers will need to use to feed our planet’s population.

Today, almost eighty years after the publication of Plowman’s Folly, the stakes are higher than ever. If more farmers don’t begin adopting conservation practices to build soil health, our descendants will face catastrophes many times greater in magnitude than the Dust Bowl. But there’s also plenty of room for optimism, and that’s the path Dave Brandt has chosen. We understand more about the science of soil health than ever before, from the micro to the macro levels. All those levels are on display on the Brandt farm. He is equally excited about invisible organisms — “We’re building the microbial herd underneath the surface” — and visible ones — “Look at the size of those earthworms!”

And, to pull back a step further, a photo Brandt loves to share is an aerial view of his fields, an image captured by drone. It’s winter, and the Brandt farm is an oasis of green in the middle of his neighbors’ bare, brown fields.