How you manage corn residue now can lead to better performance next spring, says Doug Houser, digital ag Extension specialist at Iowa State University.
“Residue management isn’t just a combine setting — it’s a yield decision,” he says. “If residue isn’t managed [at harvest], the problems multiply. By the time you see uneven stands in June, it’s too late to fix what was set in motion the previous October.”
In an online article, Houser describes a common chain reaction with heavy residue that he encourages corn growers to keep in mind — and minimize to the degree possible:
- Heavy residue in the fall traps moisture and keeps soils cooler.
- In spring, those zones are either too wet to work or create large clods if you till.
- In no-till, residue causes hair-pinning and poor seed-to-soil contact.
- Planter ride quality suffers, causing uneven seed depth.
- Uneven depth causes uneven emergence.
- Uneven emergence eventually becomes uneven plant growth and development.
- The result: lost yield potential.
Strategies To Help
Houser says he checks frequently behind the combine to make sure plant material coming through is separating and landing the way he wants.
“The thing I’m worried about is this mass of [plant material] coming through the combine will want to stick together. It can be like cotton balls and not separate like it should,” he says.
The goal is for the residue to land and form a wider spread on the ground.
“Wider-spread patterns thin out residue cover, giving you more consistent soil temperatures and better planting conditions [the following spring],” Houser says.
Champion corn grower David Hula offers four strategies he uses that other farmers might consider:
- Apply a biodigester. Two examples currently available on the market are Residue and Excavator.
- Put out some nitrogen, sulfur and sugar to stimulate biological activity.
- Take advantage of warm days to help break down residue and accelerate the decomposition.
- Consider applying a light layer of dirt if using vertical tillage.
One other factor Hula encourages farmers to consider is what their disease pressure looked like this season, and whether any is going to overwinter in the residue.
“The one positive about southern rust is that disease does not overwinter in residue,” he says.
That’s not the case for tar spot spores, which have up to 25% viability after overwintering in Midwestern fields, according to Crop Protection Network.
In cornfields where tar spot was a problem, Purdue Extension says deep tillage can “effectively bury infested corn residue and reduce fungal spore movement.” Purdue also recommends switching to soybeans next year if your rotation allows.
