No-tilling in heavy soil

Heavy soil can present challenges to farmers hoping to transition to no-till. But with patience and a whole-systems approach including cover crops, the problems can be overcome. T

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No Tilling 101: Gradually reduce tillage

For corn and soybean grower Tyler Zimmerman, who grew up farming in the Red River Valley, stopping soil erosion on his farm of 2,800 acres near Leonard, North Dakota, was one of the main reasons he wanted to switch to no-till. Over the years, he’d seen too many “black clouds of soil” billowing off tilled fields in high winds.

Stopping soil erosion also was a key motivator behind Tim Hansberger’s switch to 100% no-till in 2019. “Trying to eliminate soil erosion has been one of my main goals,” says Hansberger, who grows corn, soybeans, and cover crops on 1,200 acres in southern Minnesota near Worthington. “On windy days in the spring and winter, we used to have dust clouds over our farm, and surface water would run off and end up in a lake 15 miles away.”

Such soil erosion takes a hidden toll on farmers’ pocketbooks, reducing soil organic matter and fertility. Abbey Wick, North Dakota State University Extension soil health specialist, says, “The highest levels of fertility are in the top 2 inches of soil. As soils erode, the subsoil gets closer to the surface. The subsoil in our region can contain salts that interfere with crop growth.”

Still, erosion aside, Zimmerman admits, “I was scared to switch to 100% no-till. I thought we needed some tillage to warm up the soil and dry it out in the spring.”

He took a gradual approach to the transition by replacing fall and spring cultivating with one vertical-tillage pass in fall and spring. “Vertical tillage doesn’t till as deep as a field cultivator; it just loosens the top layer of soil,” says Zimmerman. “We found, too, that by vertical tilling, we saved time, labor, and wear and tear on the tractor.”

At the same time, upgrading to a John Deere air drill also gave Zimmerman the confidence to seed into the cornstalk residue left on the surface by vertical tilling.

Next, Zimmerman eliminated the fall vertical-tillage pass. Seeing no difference in crop emergence without it, he stopped tilling and transitioned into straight no-till with no difficulty.

Hansberger also transitioned into full no-till by first reducing tillage. From the start of his farming career, he no-tilled soybeans but strip-tilled corn, convinced the seed rows in his heavy soils needed to be bare to dry out and warm up in time for corn planting.

“But in 2018 we had a wet fall, and we didn’t get all of our strip-tilling done,” he says. “The next spring we decided to just try no-tilling the corn.”

The decision came more easily because he had just installed floating row cleaners and hydraulic downforce on the planter. “This ensures that every seed is placed at the appropriate depth,” he says.

At harvest time, the yield monitor showed no difference in yield between parts of a field that had been strip-tilled and parts that had been no-tilled. As a result, he stopped strip-tilling.

Wick notes that a transition to no-till can be helped by building a mentor network, starting small, and ensuring harvest residues are spread evenly.

No-Tilling 201: Add cover crops

“Growing cereal rye cover crops across the farm for several years sped up our transition to no-till,” says Hansberger. “Our soil can be sticky and mucky in the spring, but the rye grows early, using up extra water in the soil to help get it fit for planting.”

Recently, he has added a more diverse cover crop mix, interseeding it into corn at the V3 to V4 stage to give the cover crop a head start going into fall. He also broadcasts a diverse mix into standing soybeans or drill-seeds the cover crop after soybean harvest. “Because of our cover crops, we were more confident about eliminating tillage altogether,” he says.

Zimmerman began experimenting with cover crops a couple of years before switching to 100% no-till. The year that he made the switch, he no-tilled into a field that had been cover cropped, “and that’s when we saw the advantage of growing cover crops in a no-till situation,” he says. “In our heavier, wetter soils, the cover crops use the excess soil moisture and promote better water infiltration. The living roots create air spaces so that water and air are able to move into the soil.”

To further promote cover crop growth, he expanded his crop rotation to include spring wheat. The early harvesting of the wheat in late summer provides a window of opportunity to get good growth of a cover crop in fall.

He also plants a cover crop on all corn and soybean fields. “After harvesting the soybeans in early to mid-October, we’ll plant a cereal rye cover crop,” he says. “We interseed a cover crop in July into corn at the V4 to V5 stage.” The cover crop mix in corn typically includes cereal rye, oats, flax, and red clover.

No-Tilling 301: Build a Whole-Farm System

Adding diverse crops to the rotation gives Zimmerman diverse harvest dates and thus more windows of opportunity to plant cover crops. Now, besides corn, soybeans, and spring wheat, his cropping rotation also includes barley, oats, sunflowers, millet, and alfalfa.

He has also added livestock grazing to the system by leasing cover crops and crop aftermath to a neighbor. “Cattle are a great way to build soil health,” he says.

“Rebuilding soil health and structure are the keys to making no-till work, especially in heavy soils,” he adds. “Living soil needs water and air to infiltrate. Any tillage disrupts air passageways, and the soil life has to re-create these. By rebuilding soil structure, we create fewer problems for equipment.”

By focusing on building soil health, Zimmerman gets by with standard no-till equipment without aftermarket modifications. His only addition to the planter has been notched closing wheels to ensure better closure of seed furrows.

Having patience is another key to making no-till work, says Zimmerman. “In the spring, you need to have patience and wait until the soil is dry enough for planting,” he says. “If you go out too early, when the soil is too wet, you risk compacting the soil.”

Patience also is required to realize the benefits of no-tilling. Over time, both Zimmerman and Hansberger have nearly eliminated soil erosion. They’ve also increased water infiltration and improved trafficability.

With long-term practice, no-tilling and growing cover crops can increase soil organic matter. “Here in the Red River Valley, long-term no-tillers who also have grown cover crops have built soil organic matter to levels of more than 5%,” says Wick. “Conversely, some tillage systems in the valley have tested as low as 0.5%.”

Greater profitability can also result from no-till and cover crop systems. While crop yields remain competitive for both Zimmerman and Hansberger, for instance, input costs are significantly lower. “We don’t need great big tractors and other big equipment,” says Hansberger. “My fuel consumption is a half to a third of what it would be with a conventional tillage system.”

Resiliency is yet another benefit of no-tilling in combination with growing cover crops. “Our system is more resilient to weather extremes,” says Zimmerman. “Our crops can take more excessive heat, more drought, and more heavy rains. We have a lot of improvement to do, but we’re starting to see the benefits.”

Tips for no-tilling in heavy soil:

1. Start by reducing tillage.
2. Equip your planter with the right gear, which may include notched closing wheels, floating row cleaners, and/or hydraulic downforce. 
3. Build a mentor network.
4. Ensure harvest residue is spread evenly.
5. Add cover crops to improve water infiltration.
6. Rebuild soil structure through diverse crop rotations and incorporating livestock. 
7. Have patience to see the long-term benefits of no till. 

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