Over the last few years, growers have probably noticed more corn residue remaining in fields well into spring. This may be due to several production practice changes, including increased yields, improved corn stalks that resist decomposition, and reduced tillage. Managing residue during and after harvest — even in the spring, if necessary — is crucial to establishing uniform stands and protecting future yield potential.
It is especially important to manage residue in corn following corn, as it is less tolerant of residue than soybeans. Research suggests that corn yields may be reduced when fields have 90% residue cover within 2 inches of the seed furrow.
Effectively managing residue postharvest can be done in a few ways:
- Strip Tillage. Also known as zone tillage, strip tillage combines the soil warming and drying benefits of tillage with the soil conservation benefits of no-till. In this system, a 6- to 8-inch-wide strip is tilled in the fall, and the remaining inter-row space (usually 22 to 24 inches) with its crop residue cover remains undisturbed.
- Chopping Stalks. An alternative approach to fall tillage is chopping stalks with a flail-type or rotary blade chopper. Although very effective at sizing residue, this approach can flatten the residue profile and distributes stalk residue between the rows, reducing the advantage of planting next year's crop between last year's rows.
- Grazing. Cattle producers may consider grazing their field or baling some of their corn stalks for feed or bedding. Another option is selling corn stalks for ethanol production. In either case, only a portion of the stalks should be removed so that the benefits of stalk cover are not completely lost. It is recommended that farmers strategically remove stalks from less-erosive field areas in alternating strips year-to-year.
It is important to remember that each field is unique, and one method might not work for every field.
Poor residue management in corn-on-corn operations can result in setbacks such as delayed germination, uneven emergence, and more disease and pest activity — all of which can result in lower yield.
Whether growers manage their residue in the fall or wait until the spring, a secondary round of tillage before planting can further reduce residue and set the stage for a successful crop emergence.
