Cropland covered in green as long as possible holds a strong appeal for Keith Hartmann.

The Gibbon farmer cares deeply about soil health. He grew up on an organic dairy farm and appreciated the effort his father put into crop management. He saw the benefits of an ever-present green and diverse crop mix adding organic matter to the soil, improving soil structure, relieving soil compaction and aiding nutrient movement.

GROWING LIKE A WEED: Keith Hartmann, Gibbon, interseeds cover crops in his corn while sidedressing nitrogen with a machine he built using an air seeder, freshening strips, firming wheels and a fertilizer applicator.

Hartmann knew that cover crops would provide the same benefits, and he thought about how to establish them in his corn-soybean rotations. This is one of the challenges most crop farmers face: how and when to seed cover crops. Some do aerial seeding; some do over-the-canopy seeding late in the growing season.

Hartmann was curious about interseeding cover crops into standing corn early in the growing season. He did some research on interseeding, but couldn't find equipment to do the job he wanted on his acreage.

So, he did what any farmer does when faced with a lack of tools — he built his own.

During the winter of 2014, Hartmann made a three-row cover crop interseeder using a Gandy gravity drop seeder, Yetter strip fresheners and firming wheels. He seeded 25 acres in early June 2015 when corn was at the V6 stage, around 12 to 18 inches tall.

“After I seeded, the cover crop was up in three days. When the cover crop was about 4 inches tall, the corn canopied at V10, blocking sunlight. The cover crop went dormant until September,” Hartmann says. "Then the corn dried and leaves dropped, and the cover crop flourished.”

That first year, Hartmann also conducted yield trials, planting three replicated strips, each 2,000 feet long. He also conducted stalk nitrate tests on corn.

Not only did cover crops not rob nitrogen from the corn, but they did not affect corn yields either.

Buoyed by the success, Hartmann decided to interseed more acreage in cover crops this year. He wanted to sidedress N while doing so. So he built a 12-row N sidedresser-interseeder.

Check in tomorrow on The Farmer’s website and learn more about Hartmann’s latest invention.