More northern Corn Belt farmers are planting continuous corn, and that means more hard-to-handle residue left in fields.

Higher plant populations, better-yielding hybrids, less aggressive tillage and the cold climate – which slows down decay – all increase the mounds of debris.

Surface residue lowers soil temperatures, hindering germination and early growth. Excess corn debris can also tie up nitrogen (N) and cause planting problems, reduced stands and more disease.

“Residue management is our No. 1 challenge with corn after corn,” says John Nelson, who farms with his son Jared at Hanska, MN. The Nelsons have a little over half of their 2,800-acre operation in continuous corn. “We’ve been tweaking our tillage and fertilizer for 10 years and we’ve learned a lot, but we still make mistakes.”

A 200-bu. corn crop creates more than 10,000 lbs./acre of residue. Here are some tips from experienced “residue managers” on how to handle all that trash.

 

*Consider your rotation.

For John Nelson, economics favor corn over soybeans. “I have a lot of high-pH soil, and soybeans don’t do well,” he says. But his land can produce 200+-bu. corn crops. Last year, his whole-farm average was 215 bu./acre.

In fact, throughout the northern Corn Belt, “There’s a comparative yield advantage for corn over soybeans that’s much higher than in the central Corn Belt states,” saysJeff Coulter, University of Minnesota Extension corn agronomist. Corn yields up north have climbed faster than soybean yields, and northern states appear “better suited to corn than soybeans when compared to other regions.”

Still, crop rotation typically increases both corn and soybean yields by 5-10%, Coulter notes. As an alternative to continuous corn, he suggests a corn-corn-soybean rotation.

 

*Size and spread residue evenly.

The Nelsons use a John Deere chopping corn head with stalk stompers to process corn stalks at harvesttime.

It’s really important to spread residue evenly, says Clyde Tiffany, a Pioneer Hi-Bred field agronomist in Minnesota. Combines with wide header widths may concentrate residue in swaths. Windrowed corn debris reflects more sunlight in the spring and slows soil warming, resulting in uneven emergence in rows where residue accumulated.

After harvest, Nelson uses a Case IH 330 vertical-tillage tool, at high speed, to size residue before disk ripping. Closely spaced wavy coulters shatter brace roots and tear up root balls, knocking the soil out of them, Nelson says.

Sizing residue aids incorporation and provides more entry points for fungi and soil microbes, the organisms that break down residue, Tiffany says.