A month after planting a cover crop mix, Brian Johnson’s field was thick with leafy radishes and bright green spears of sorghum Sudan grass. In another month, the cows would be turned out for a few weeks of grazing this leafy mix.
It’s all part of a plan to prepare the field, which grew oats this season, for a healthy corn crop next year. Come spring, the cover crop will have decomposed, leaving a soft soil bed for seeding corn. Nutrients from the cover crop and the cows will be left behind as well, helping the corn to a strong start.
The busyness of corn and soybean harvest was still ahead of him, but Johnson was already looking forward to pulling his planter through that field just north of his Frankfort, South Dakota home. Cover crops make the soil conditions just right for planting.
“It’s definitely mellow,” Brian said. “It’s my ideal seed bed. It’s like butter.”
Brian doesn’t till his fields. He aims his seed within the 2-inch row where the cover crops are growing now. That’s where they’ll land in the softest soil. When the corn or soybeans put down roots, they’ll follow the holes where radishes grew deep into the soil before turning to mush with winter’s freeze. Wheat straw residue next to the planting strip holds in moisture and shades the ground until the corn canopies.
Working the soil this way is known as bio stripping. The Johnsons have been seeing big benefits.
Brian farms with his wife Jamie and his parents Alan and Mickie Johnson. They’ve managed many of their fields without tilling for nearly 30 years, and they’ve been using cover crops in their rotation of corn, soybeans and wheat for nearly a decade.
Now Jamie, who comes from a livestock background, is encouraging them to add to that diversity using their herd of registered black Angus cattle. She’d like to see the cows out grazing residue after harvest.
Already, they’ve created more pasture land by putting their least productive ground back into grass. It’s the opposite of the trend in 2009 and 2010 when many grassland acres in the area were plowed to plant crops because prices were so high. The area where the Johnsons farm south of Frankfort is known for its high-producing corn ground. Many farmers there plowed the grassland for crops in those good years, but some of the land there turned out to have issues with poor drainage and salinity, and now it doesn’t pay well at all.
Brian said he’s happy to have his worst fields back in grass.
“It looks fabulous and I don’t have to fight those issues anymore,” he said.
That’s how it should be because it works best for the land, Jamie said. “It was made for livestock,” she added.
Using cattle in their crop management plan makes sense, as well. The cows will graze the cover crops for about three weeks or longer if they supplement their feed with the baled oats at the field’s edge. Feeding cattle this way means less work and less hay every day, she pointed out.
“It needs to be a cohesive operation that works together,” she said.
The cows get a big benefit, too. Cover crops extend their grazing season with nutritious forages, and they love the turnips and radishes in the mix.
“It’s ice cream all over the place,” said Shane Jordan, district conservationist with the Natural Resources Conservation Service in Redfield who has worked with the Johnson family for several years. He helped the family work through salinity issues by planting salt-tolerant cover crops like wheatgrass, using federal incentives through the Conservation Stewardship Program.
Planting cover crops has become a normal part of the Johnson’s management program. That’s what NRCS likes to see, Shane said. The program is meant to encourage farmers to continue these soil-building practices on their own.
“The challenge is getting a small grain in the rotation,” he said.
Producers like what it does for their soil, but they don’t see enough of a return on their investment to stick with it—especially when the wheat market is down like it is now. The best benefits come after eight to 10 years of diversified cropping, Shane said.
The Johnsons plant wheat on their more challenging fields rather than using their top-producing corn ground. Brian estimates they get a 15-bushel bump when corn follows their wheat crop, in addition to other benefits.
“You’re fixing weed problems and salinity problems,” he said.
Diversifying crops helps break up issues with weeds such as waterhemp and kochia.
The Johnsons worked over the years to fine tune their cover crop seeding rates and seed placement. Brian needed to add some special equipment to make it possible for his planter to handle the seeds in the cover crop mix. He got some questions when he special ordered planter plates for sugar beets, a crop grown in neighboring North Dakota and Minnesota but not at all common in South Dakota.
Some cover crop mix needs to be planted with a drill because the seed sizes aren’t uniform enough for the planter to handle. Brian used a John Deere 750 drill to plant his grazing mix. The mix of millet, radish, turnip and sorghum Sudan grass was planted in 20-inch rows. Before it went in, the local cooperative applied phosphorus and potassium. Brian will add nitrogen when he plants corn in the spring and when the plant is at about its V5 growth stage.
This year, proved ideal conditions for getting a cover crop started. The Johnsons harvested oats at the beginning of August and planted the cover crop mix as soon as the bales were moved, then the rain came.
“It’s got the start that it needed,” Brian said.
The Johnsons also got a head start on harvest.
Rather than rushing to roll combines through all their fields in October and November and put the lid on the bin before winter hits, the Johnsons can knock out a few hundred acres by harvesting their wheat in August.
“That’s stressful when you’re up against a blizzard,” Jamie said, recalling the harvest season three years ago when they worked past midnight to finish the work ahead of a November snowstorm.
Spreading out that harvest-time workload is another benefit of growing small grains and cover crops she likes best.
