Dave and Mark Legvold are longtime soil health proponents who are always looking for ways to keep organic matter in the soil and green covering on top.
The former science teachers farm 750 acres of strip-tilled corn and no-till soybeans in Northfield, Minn. Their most recent venture is seeding annual ryegrass and cool-season cover crops into V3-V6 corn while applying 28% liquid nitrogen. They do so with a homemade sidedress toolbar built by Mark.
After doing some research, Mark found Meyer salt spreaders available at Northern Tool that could do the job of broadcasting seed. He bought two and attached them to a 12-row 30-inch toolbar. The cost of the finished implement was around $2,300.
In June 2019, he spread a cover crop seed mix of ryegrass, tillage radish, rapeseed, clover with winter wheat added as a carrier. He sowed 15 pounds per acre at 7.5 mph into the young corn.
The cover crop seeded this way last season grew well. The Legvolds took note of two things impacting the practice, however: sunlight and herbicide residuals.
“A major issue to assure cover crop coverage is sunlight,” Dave says. “Cover crops planted in north-south [corn] rows don’t do as well as east-west rows. Think of the passage of the sun throughout the day. Also, we’re still learning about which herbicide to use [to terminate the growing cover crop] without impacting emergence and survival of the [next cover] crop.”
The Legvolds have used generic glyphosate and a chemical with a short residual.
“We’re learning to pay attention to the half-life of chemicals,” Dave says. “If it’s short, it degrades faster and the [new] cover crop is more successful coming up. If it’s longer, [herbicide] will last weeks to months in the soil.”
This growing season, Mark says they used just the generic glyphosate and no residual.
“We’re trying to limit use as much as we can,” he says.
In the end, the goal is all about keeping green plants on fields as long as possible. Along with interseeding, the Legvolds have hired aerial application of ryegrass seed in the fall for a cover crop and drilled cover crop seed into soybean acres.
“I’d like to continue to build on that success,” Mark says. “I’d like to continue to learn the science and fun of cover crops.”
Learn more by watching YouTube videos of the Legvolds discussing their cover crop philosophy.