Bio Strip-till Provides Ideal Growing Conditions for Corn
Bio strip-till gives newly planted corn a jump-start at Joe Breker’s no-till farm near Havana, North Dakota. He plants the corn precisely into the rows where a cover crop of turnips, radishes, and flax grew the previous fall.
“Because the radishes and turnips decompose so quickly over winter and early spring, they create a seedbed that’s mellow, and they don’t interfere with the planting process,” he says. “I get good early-stand establishment and healthy corn.”
Breker first saw bio strip-till at work in a field trial six years ago at the Conservation Cropping Systems Project (CCSP) Farm at Forman, North Dakota.
“The field trial had been put in place because the farm manager had stumbled across some data suggesting that corn planted on top of radishes performed better than corn planted in between the rows,” says Breker. “Based on the interesting results I saw at the CCSP Farm, I set up my own on-farm trial. I’ve been doing bio strip-till now for four years.”
The bio strip-till further diversifies Breker’s already diverse crop and cover crop sequences. He grows corn, then soybeans, followed by Jackhammer radishes to harvest as commercial seed for cover crops. After the radishes and before going back to corn in the rotation, he grows either spring wheat or a winter cereal like winter wheat or rye.
“The winter cereals are actually cover crops because they grow in the fall,” he says.
To provide a fall cover crop after corn, he seeds rye into the corn by aerial application in mid-September. The bio strip-till cover crops go into cereal stubble. The diverse planting comprises twin rows of turnips, radishes, and flax planted 6 inches apart on 30-inch centers. In a second operation, he plants field peas down the middle of the 30-inch centers.
“With the turnips and radishes, I put on 30 units of nitrogen (N) per acre to help them get started and grow aggressively,” says Breker. “I omit the fertilizer if I think there’s residual N in the soil. The deep roots of the turnips and radishes will scavenge N that escaped from the previous crop.”
The brassicas have demonstrated good adaptability to Breker’s high-pH soils. “I have a lot of calcium in my soil, and it tends to have high-pH levels,” he says. “Most of my ground is poorly drained, so salts can accumulate, leading to salinity. But the turnips and radishes grow well in those conditions.”
Along with the brassicas in the bio strip-till, Breker grows flax in order to support the colonization of beneficial mycorrhizal fungi in the soil. “Turnips and radishes are not mycorrhizal-friendly crops,” he says.
All three crops winterkill, and the low-carbon brassica tubers rapidly decompose, leaving root cavities in the soil. This contributes to a mellowing of the seedbed for the following year’s corn planting.
The peas planted down the middle of the 30-inch centers between rows fix nitrogen in the soil. “This year, I planted rye along with the peas,” says Breker. “The rye will overwinter and grow in between the corn rows in the spring. I added the rye to the mix of crops in the bio strip-till in order to have live roots in the ground that would survive the winter.”
He plants the bio strip-till with an Amity single disk drill with residue managers. “I use RTK GPS to accurately place rows in between each other and to seed into the following year,” says Breker.
The bio strip-till creates the ideal environment for getting corn off to a fast start.
“For planting the corn into, I want a dark strip of soil that’s mellow and rich. That helps the corn get a good start,” he says. “I can do the same thing with strip-tillage, but I’m trying to do it with plants and less mechanical tillage. By removing some surface residue with the residue managers on the planter and by planting a bio strip of high-N, low-carbon plants that decompose rapidly, I do end up with a mellow, dark strip with high nutrient content.”
High soil health permits Breker to reduce N applications. “This year, I applied between 60 and 80 pounds of N to corn,” he says. “The year before, I put down only 60 pounds. That’s about half the application rate typically used in my area. But even if I were not doing bio strip-till, the soil would still have a low need for added fertility. That results from an accumulation of years of no-till farming and from growing cover crops."
Soil Health Grows
After 35 years of no-till and 16 years of growing cover crops, the soil health on Joe Breker’s farm near Havana, North Dakota, has steadily improved.
“When I started out, the soils on much of my farm tested 3.5% to 5% organic matter,” he says. “After 20 years of no-till, the level of organic matter grew to 5% and 5.5%. It leveled off, and then I started growing cover crops, and organic matter ratcheted up. Most of the fields now test 6% and 7% organic matter.
“Because I’m in the tallgrass-prairie region, I have good, deep soils with high moisture-holding capacity,” he says. “Originally, the soil probably had 6% to 8% organic matter, so I’m getting close to restoring soil organic matter to its original condition.”
The high-clay content of the soils requires Breker’s attention to nitrogen-to-carbon ratios in residue in order to ensure the annual recycling that prevents excessive buildup of residue. In the bio strip-till, the mix of turnips, radishes, and peas provides the high-nitrogen, low-carbon residue that decomposes rapidly and provides nutrients readily available to corn, in particular. The colonization of mycorrhizal fungi fostered by the flax further helps nutrient availability.
“I have more soil biology as a result of less tillage, accumulating plant material, and increasing moisture-holding capacity in the soil,” he says.
The overall result is a growth in organic matter and a 50% reduction in N-application rates.
In recognition of his work in improving soil quality, Breker was one of three farmers who received the 2015 Responsible Nutrient Management Award at the National No-Tillage Conference.