Grazing corn residue can curb volunteer corn and stretch feed

Grazing cattle on harvested corn fields can help reduce volunteer corn and the need for herbicide while giving livestock producers another feed source, according to Kim Ricardo, a forage field specialist at South Dakota State University Extension.

Volunteer corn develops when leftover corn grain in a field germinates. “Because they are selective grazers and they are going to go after that corn grain and those husks and leaves first,” Ricardo said. Cattle therefore can remove the grain that produces unwanted plants in the next crop, while potentially lowering the herbicide required to manage volunteer corn.

The practice matters most when drought has weakened corn and left more grain in the field. It also gives producers a way to use corn residue when feed costs continue to increase, although the recommendation comes without a calculated herbicide saving or a universal grazing rate. The case is practical rather than quantified: manage weeds, stretch forage and recycle nutrients, while treating higher crop yields as a possibility to test.

Why does volunteer corn rise after dry years?

Ricardo said volunteer corn increases following dry years because drought stress weakens plants. In corn, that stress raises the incidence of lodged ears, which fall, and dropped ears, which remain in the field. The grain then sits where it can germinate and produce volunteer plants in the following crop.

Her explanation does not cover every dry year, so this is a risk pattern rather than a guaranteed annual increase. Nor does it separate how much grain fell from how much of that grain germinated.

In short, drought can leave behind the corn grain that creates next year’s weed problem.

Can corn residue stretch the feed supply?

Beyond weed control, the residue itself is feed. “Grazing corn residue is a really useful feed resource for livestock producers, even just beyond the thought of volunteer corn. It can be a really great way to extend grazing days,” Ricardo said.

Extended grazing can help producers preserve harvested feed inventory that a dry period has limited or stretched. Grazing the residue therefore adds an alternative feed option at a time when feed costs continue to increase, offering producers more flexibility in how they allocate forage between harvested crops and livestock.

That benefit depends on the amount of residue available, not just on the presence of cattle. Ricardo did not set an animals-per-acre standard, so producers still need a field-level estimate.

In practical terms, grazing can ease pressure on stored feed without promising a fixed feed-cost saving.

What does livestock add to the soil?

Ricardo said livestock bring added nutrients into harvested fields and can benefit soil health through nutrient cycling. She also cited several research studies showing that grazing corn residue does not cause much compaction, though she did not provide details on those studies in the discussion.

The qualification is soil timing. Farmers should not turn cattle onto fields when the soil is very wet or after fields have thawed following a freeze. Her warning keeps the grazing recommendation tied to field conditions rather than treating it as a blanket rule.

The nutrient case is promising, but the cited research does not replace a producer’s field-level assessment.

Can grazing raise the next crop’s yield?

Ricardo said grazing corn residue can potentially increase yields in following crops, including soybeans. She was careful with the claim: the increase may not occur every year, and she described the idea as a test of the belief that livestock can benefit a field through nutrient cycling.

No specific yield gain, test location or response rate accompanies the suggestion. For now, treat higher yields as something to test, not a budgeted gain; the more concrete case remains volunteer corn control and feed supply.

How should producers set the stocking rate?

Stocking rates depend on the acreage and the amount of residue available. Ricardo said the arrangement requires an agreement between the livestock producer and the farmer, rather than a standard rate that applies to every field.

Producers would need to:

• Estimate the acreage and usable corn residue in the harvested field.
• Match cattle numbers and grazing days to that supply.
• Avoid turnout on very wet fields or after a freeze-thaw event.
• Test any claimed follow-crop yield benefit on the operation instead of treating it as guaranteed.

The next decision is field-specific: whether available residue can support an agreed stocking rate while reducing volunteer corn and avoiding poorly timed grazing.