*Use fall tillage to speed up residue decomposition.

Continuous corn responds more to tillage than corn after soybeans, Coulter says – especially on heavy soils.

Two decades of continuous-corn trials at the University of Wisconsin found that fall chisel tillage improved yields 5-8% for second-year corn, and 8-11% for consecutive years of corn.

However, tillage did not improve corn yields for first-year corn following soybeans.

“If you’re in a corn-soybean rotation, you can get by without tillage,” says University of Wisconsin Extension Corn Agronomist Joe Lauer. Even in second-year corn, it’s not always profitable to chisel plow, he says. “But when you get deeper into consecutive years of corn, there is an advantage to tillage.”

John Nelson follows vertical tillage on continuous-corn ground with a Case IH 870 disk ripper, equipped with shanks spaced at 24 in. and a harrow. His fall tillage operations leave about 40% residue cover for the winter. “The residue is fine so it breaks down better.”

Elkton, SD, farmer Spencar Diedrich has experimented with several types of tillage for continuous corn, which represents about 75% of his family’s operation. The Diedrichs don’t use tillage for soybeans, but have found corn-on-corn “tough to do without tillage.”

They tried fall strip-till, but had problems with residue blowing over the strips, slowing spring warm-up. They’ve gotten better results with full-width tillage, Diedrich says.

For several years, they used a Sunflower land finisher in the fall. Recently, they switched to a Wishek disk, which both chops and incorporates residue into the top 6 in. of soil. Fields that will be planted to corn again get two fall passes with the Wishek disk, if there’s time, at a cost of $8/acre/pass.

Move your fall tillage for continuous corn as early as possible, Coulter adds, so shredded residue has time to decompose. Soil microbes are most active at soil temperatures above 50° F.

 

*If you have a market, harvest some residue.

The addition of distillers’ grains to cattle diets offers an “excellent opportunity to use corn stalks as feed,” says Gregg Carlson, South Dakota State University plant scientist.

In cattle diets, distillers’ grains plus corn stalks provide about the same level of total digestible nutrients as corn grain. “This is a great opportunity to increase profitability and productivity,” he says, “especially if you put manure back on the field.”

Removing some residue raises yields, lets you reduce tillageand has agronomic benefits, too, Coulter says.

Illinois research found that grain yields for the following corn crop rose about 5% when half or all of the corn residue was removed the previous fall. Nitrogen requirements fell about 13%, and no-till yields were comparable to those with conventional tillage.

In continuous corn with disk-rip tillage, you can sustainably remove about 40% of residue, Coulter says. Choose productive fields with low erosion risk and rotate residue harvest among fields. Also remember that you will need to replace the nutrients in harvested stover, especially potassium.

Harvesting more corn residue than just the cobs is not usually sustainable in a corn-soybean rotation, or on erodible or droughty soils, Coulter adds.

 

*Skip N to break down cornstalks, but consider adding sulfur.

The Diedrichs of South Dakota used to apply a 28% UAN solution to corn residue in the fall to speed up decomposition, but decided it didn’t pay.

Midwest research confirms that adding N to corn stalks in the fall doesn’t accelerate residue breakdown, says Wisconsin’s Lauer. That’s because residue decomposition in the northern Corn Belt is limited by cold soil temperatures – not a lack of N. Treating corn stalks with N just adds unnecessary expense and leaching risk, he adds.

Minnesota grower John Nelson applies 5 gal./acre of ammonium thiosulfate in a band over the top of the corn rows at planting. “Sulfur deficiencies are common now,” Coulter says. In Minnesota research trials, “We’re seeing an early season response to sulfur in continuous corn, with taller, larger and more uniform plants.”

 

*Use row cleaners.

Row cleaners on the planter are essential tools for effective residue management in continuous corn, Pioneer’s Tiffany says. A 6-10-in. residue-free band at planting improves seed-to-soil contact and raises soil temperatures in the seed zone.