Residue Management Options
How much residue is too much? What’s the best way to manage it? The answers will depend on what your goals are for residue management, says Mark Licht, Iowa State University Extension cropping systems specialist.
From a soil erosion standpoint, Licht says 50% to 70% of corn residue should be left on the field surface. Before hauling all that iron into the field this fall, take an extra minute to ask yourself if it’s really necessary.
Benefits of residue
Leaving corn residue on your field provides a protective blanket for your soil.
“Residue increases water infiltration,” says Licht. “You’re reducing water runoff from the field and erosion.”
The protective blanket of residue does more than that.
“Corn residue provides moisture retention,” says Chad Watts, executive director of the Conservation Technology Information Center. “Depending on your climate, that could be a good thing or a bad thing.”
A wet spring could delay planting, says Watts. Another consideration is for nitrogen needs. “You may need to compensate for the residue breakdown, which ties up the soil biology, with starter fertilizer,” explains Watts. “These are all issues you can plan for and manage.”
Think about No-till
“You can do no-till on any soil,” says Watts. However, he admits it’s not easy on all soils.
“It’s more challenging on heavy, clay soils, but it’s more rewarding if you do less disturbance,” says Watts. “It can be done. If you reduce tillage, oftentimes cover crops are a good transition.”
The cover crop will penetrate through compacted soil layers. That penetration results in more air and water movement.
Worried about cover crop residue? Relax. Odds are, it won’t be a problem.
“If it’s a cover crop grown in the fall that will winter-kill, it won’t have an impact,” says Licht.
However, if an overwintering cover crop is selected, there be can be challenges because the roots won’t be decomposed.
“A fibrous root from cover crops can present some challenges during planting,” says Licht. He suggests dealing with those obstacles by making sure your planter row unit downforce and pressure on the closing wheels are adjusted properly. Those adjustments will ensure soil-to-seed contact.
Set up your planter so it can manage the residue, says Watts.
“Have residue managers on the front to move the residue to the side as you go through the field with the planter, closing wheels to make sure the trench closes behind you, and seed firmers,” says Watts. “That seems to be a pretty good system.”
Be sure to consider the slope of the field before performing tillage. Any field that has a slope greater than 5% shouldn’t have aggressive tillage passes made, says Licht.
Factor Crop Rotation
“You can make residue work in about any cropping system,” says Watts. “With a lot of today’s equipment, systems have been created for dealing with heavy residue.” Because of machinery improvements, residue should be less of an issue than it was even 15 years ago, he says.
Soybean residue won’t be a problem, says Watts.
If you grow corn following corn, there may be more residue that you need to manage. In Watts’ mind, residue management starts with the combine. It should be viewed as the first tool to manage residue.
“Get a combine that chops up the residue well, and then you’re already ahead of the game,” says Watts. “You want a combine that does a good job chopping and evenly spreading residue.”
Test the water with strip-till
A compromise for those curious about no-till, but not ready for the commitment, is strip-till.
“One option that is a slightly better alternative is going with a strip-till system,” says Licht. “With strip-till, you’re creating a tillage zone of roughly 8 inches to 10 inches. That zone will be turned into the seedbed.”
Two thirds of the soil is left undisturbed with strip-till. This allows you to have the benefits of tillage in the seedbed along with the benefits of no-till, says Licht.
“The planter gets a little better seed-to-soil contact with this system,” says Licht. “The undisturbed areas help to build aggregate stability and a healthier environment as far as the field is concerned.”
Ultimately, if you’re wanting to go to a true no-till system, you can use strip-till as a transition stage. You still get some of the soil benefits of leaving part of the soil undisturbed.
“I’m hesitant to say you should never do tillage; it’s something that should be kept in the toolbox,” says Watts. “There could be times when you’ll need to do a light tillage pass, but minimizing tillage will add soil health benefits. You’re going to create a more resilient soil.”
Chopping or rolling stalks is one option to speed up the decomposition of stalks.
“If you chop stalks, they can get caught in the wind and you lose the residue from the field. Most planters today are able to plant into residue fairly well,” says Licht.
“Some people will chop or roll the residue, but with today’s equipment, I’m not sure it’s all that necessary,” says Watts. “Instead, it’s a systems approach to managing the residue. It all starts with the combine. If you need to, address the rest with the planter."
“CTIC has been in a position for a long time advocating for higher levels for residue,” says Watts.
“The more residue you can leave on the surface, the more shielding you get from rainfall. To the extent you can leave it, the better off the soil is.”