Cold spring soils are sparking a hot new form of tillage. Shallow vertical tillage tools slice crop residue and loosen the top layer of soil while leaving most of the residue on the surface to protect soil from erosion. The practice speeds up residue breakdown and improves spring planting conditions – without sacrificing the soil conservation benefits of high residue cover.
Shallow vertical tillage is hot these days, says Mike Staton, Michigan State University soybean agronomist. What’s driving it, he says, is the goal to manage an increased amount of corn residue with the least amount of tillage. Higher corn populations and yields, stronger stalks and more years of continuous corn are generating mounds of sturdy stover. All that residue slows soil warming and makes it tougher to achieve good seed-to-soil contact.
Curt Weisenbeck, Agronomic Consulting, Durand, Wis., works with quite a few former no-tillers who now use shallow vertical tillage to handle “quite an accumulation of residue. With our cold soils in the spring, you can have some decline in yield potential.” For preparing the seedbed, “it’s as good a tool as you will find for a one-pass system,” he says. “It helps tremendously with warming cold soils.” That can improve yield potential 10%-15%, he estimates. “We’re able to warm up the soil better, we get better fertilizer incorporation, better mineralization of nitrogen and we can do a better job with the planter.”
Jay Furseth used to be all no-till for soybeans at his Stoughton, Wis. grain and dairy farm, but the heavy accumulation of corn stalks interfered with soil warm-up and planting, and soybean harvesting. “All the residue made it hard to keep the combine heads close to the ground.”
Last fall, the Furseths ran a 30-ft. Great Plains Turbo Max shallow vertical-tillage tool over corn stalks. This spring, “the planter pulled easier, versus straight no-till,” Jay says, and less down pressure was needed for good seed placement. The Furseths dropped their soybean population by about 10,000 seeds/acre “because of the better seedbed.”
This fall, the Furseths used the tool to help incorporate dairy manure on harvested corn silage fields. Mixing “top layers of soil with a conservative tillage pass that maintains large amounts of residue” can help reduce phosphorus losses, says Kevan Klingberg, University of Wisconsin Extension outreach specialist.
Shallow vertical tillage is also an option for growers who want to reduce – but not eliminate – tillage, says Trevor Dybevik, Great Plains territory manager for Wisconsin and Minnesota.
Doug Olson raises corn and soybeans on the erodible hills of Wisconsin’s Driftless Area, near Mondovi. He has used shallow vertical tillage for several years to manage crop residue on his sensitive terrain. “I like leaving the residue on top of the soil. That’s how our topsoil is made – not by plowing.” Shallow vertical tillage, at 8-10 mph, “gets my stalks chopped in the fall very quickly,” he says. “I like it on our side hills.” In the spring, the chopped residue flows through the planter better, he says, “so we get good seed placement. He gets good water infiltration, it saves time, and he hasn’t seen any yield loss, he says.
Many different implements are marketed as shallow vertical tillage tools. All are designed to cut residue at high speed and penetrate 1-4 in. into the soil. But not all are strictly vertical, Dybevik says. “True” vertical tillage tools don’t invert soil or move it from side to side, he says, making them different from disks or field cultivators, which move soil horizontally, as well as vertically, and may create a compaction layer.
Shallow vertical tillage machines consist of smooth, fluted or notched blades, which are mounted straight-up-and-down on the toolbar, either in gangs or individually, and cut a strip about 2 in. wide. Rear finishing attachments, such as tine harrows and rolling baskets, mix some soil with the residue and level the surface a bit. The tillage operation is usually done at a diagonal to the crop rows.
More aggressive implements have angled gangs, narrower blade spacings or concave, curved or rippled blades, which throw more soil sideways. Some models have adjustable gang angles, allowing growers to increase or decrease tillage intensity on the go.
These implements require about 10 hp/ft. to pull, and cost around $2,000/ft., Dybevik says. Ownership, fuel and labor costs run about $10/acre, Michigan’s Staton estimates.
Doug Olson owns three 30-ft. Summers Supercoulter Plus vertical-tillage machines with rolling choppers – each with a different blade configuration. After corn harvest, he uses a machine equipped with wavy blades to slice stalks into 5- or 6-in. pieces. The wavy blades also throw some soil, “so you get more tillage effect. I use them in the fall for more incorporation of residue.” In the spring, he uses less aggressive smooth blades “for aeration, to warm the soil and prepare the seedbed.”
Olson’s corn ground gets two vertical tillage passes: one in the fall to size the residue and promote breakdown, and one in the spring to fluff up the residue and loosen soil in the planting zone. Soybeans, which respond less to tillage, get only one pass in the spring, a few days ahead of the planter.
The timing of shallow vertical tillage depends on your goals and soil conditions, says DeAnn Presley, a soil scientist at Kansas State University. If your object is to break down residue faster, a fall pass works best, giving soil microbes more time to work their magic. But you sacrifice the conservation benefits of leaving residue intact over the winter, she says. “One weakness of all vertical-tillage tools is they don’t have a lot of ability to anchor residue in the soil. They cut residue well and leave it on the surface. But if it’s sloping ground or ground prone to wind erosion, the residue can move. We’ve seen that happen in eastern and western Kansas.”
If erosion is a risk, a spring pass is preferable, Presley says. However, a spring operation raises the risk of tractor-wheel compaction, says Purdue Extension Agronomist Tony Vyn.
During several cold, wet springs in northwestern Minnesota and eastern North Dakota, though, shallow vertical tillage was the only practical option for seedbed prep, says Jodi DeJong-Hughes, Minnesota Extension regional educator.
“It’s shallow, straight, and there are no shanks that can smear the soil. It just warmed and dried the soil enough so people could plant.” In some cases, she adds, “It made the difference between being able to plant and preventing planting.”
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