Leaving corn residue on fields provides a protective blanket for soil. This reduces erosion and water runoff by increasing water infiltration. But as good as this sounds, many farmers understandably ask, “How much residue is too much?”
Crop specialists generally agree that approximately 60 percent of corn residue should be left on the surface of a field. Which begs the question, “Is fall tillage really necessary?”
Corn residue provides moisture retention which, depending on the climate, can be seen as a positive or a negative since a wet spring could delay planting. Nitrogen is another issue to consider since you may need to compensate for the residue breakdown with starter fertilizer.
No-till is easier to manage on some soils than others. Heavy clay soils, for example, can be tough. However, no-till can still be a good decision on this type of soil if you decide to go the no-till route. That’s because the cover crop will penetrate through even the most compact soil, allowing air and water to move through it.
Cover crop residue is not usually a problem, especially if it is a cover crop that is grown in the fall since winter-kill means it won’t have an effect. The same cannot be said of an overwintering cover crop. In that case, roots won’t decompose and that can make planting more challenging. However, modern planting equipment has settings to deal with those challenges.
Soybean residue isn’t a problem but corn grown following corn may leave more residue. But, again, your combine should be able to chop up the residue and then evenly spread it out, eliminating most issues.
If you aren’t ready to take the leap to no-till, strip-till is a good option. Strip-till means you basically create a tillage zone about 8 to 10 inches which is turned into the seedbed. A majority of the soil is still left undisturbed, though. This allows for the benefit of tillage in the seedbed coupled with the additional benefits of no-till.
With strip-till, the planter is able to get better seed-to-soil contact but still reduce tillage in the field. This means a healthier and more resilient field overall.
Whether you choose no-till or strip-till, the key is to leave as much residue as you can on the surface of the field as possible.