With harvest approaching, residue management is top of mind for no-tillers. At the 2015 National Strip-Tillage Conference held last week in Iowa City, Iowa, Midwest Bio-Tech vice president Doug Miller covered an important component of residue management: Getting corn, wheat and soybean residue to break down.

Miller says there are four components required for residue decay:

  1. Microbial activity
  2. Warm temperatures
  3. Moisture
  4. Nutrients, especially nitrogen (N)

The key is if any one of these factors is limited, residue won’t decay as it should, Miller says. For example, if there’s plenty of moisture but the temperature is cool, residue won’t break down. The same goes if the air temperature is warm but conditions are dry. 

While you can’t always control these factors, particularly the weather, there are management steps you can try to help the residue decay process. Leaving the soil undisturbed already assists microbial activity and helps conserve moisture. And of course, you can apply fertilizer if you’re short on nutrients. 

You can also consider any practices you’re doing that may be hurting one of the four components. Miller says fungal-type species in the soil are the most important species in breaking down residue, and anything you do to hurt them is going to hurt residue decay. 

Are you using anhydrous ammonia? If so, that may be your problem. Miller says it will take months for fungi to recover after being in contact with this particular N source. Fungicides are also a problem, because in addition to the bad fungi they’re killing in crop diseases, they’re also harming the good fungi. 

Considering applying sugar to your residue? Skip it. Miller says that sugar increases carbon, which impacts the carbon-to-N ratio but doesn’t provide any N, which makes it even harder for soil microorganisms to break residue down.

Have you made any adjustments to your residue management program that’s improved the decay process? Leave a comment below and share your tips and tricks for helping residue decompose.