For producers who raise both corn and beef cows, the combine does not necessarily mark the end of the cornfield’s productive season. After grain harvest, the field still contains dropped corn, husks and leaves that can provide up to 60 days of economical winter grazing.

Corn-residue grazing can substantially reduce winter feed costs while also helping manage heavy residue. Just as importantly, long-term research indicates that properly managed grazing does not create soil compaction or reduce the yield of the next corn or soybean crop. In several Nebraska studies, crop yields after grazing were equal to or slightly greater than yields from ungrazed fields.

Cows harvest the most valuable residue first

A harvested cornfield contains five primary feed components: dropped grain, husks, leaves, cobs and stalks.

Cows should obtain a reasonably good diet early in the grazing period even though a laboratory analysis of the entire field might suggest that corn residue is poor-quality feed. I had a case a few years ago where the owner tested over-mature fescue hay along with his corn crop residue, and the corn residue was higher in energy. Again, early in the grazing season, corn crop residue can be quite valuable to a dry beef cow.

Cattle are selective grazers. They generally consume dropped corn first, followed by husks and leaves. Cobs and lower stalks are much less palatable and have relatively little feed value.

This selectivity also explains why cattle should not be forced to “clean up” a field. Once most of the grain, husks and leaves are gone, the remaining stalks will not provide enough energy or protein for your cows.

Corn residue is generally best suited to mature, dry, spring-calving cows in midgestation. Monitor cows’ body condition and adjust supplementation as residue quality declines. Salt, minerals, vitamin A and an adequate water supply remain essential.

Producers should also scout fields before turnout for excessive down corn. A large amount of accessible grain can cause acidosis, founder or death, especially when hungry cattle are first introduced.

Timing of residue grazing

I just read an article by Jason Tower, superintendent of the Southern Indiana Purdue Ag Center and he outlined what to graze first this fall. Because corn crop residue is lying on the ground, it deteriorates over time and should be grazed first. Wherever the cows are when you finish harvesting a field, move the cows to that newly harvested field as soon as the combine leaves the field.

If you have cover crops, graze them next, followed by non-fescue grasses that were stockpiled, and graze stockpiled tall fescue last. His article goes into much greater detail, and I would be glad to share it with anyone. Email me at wmarkhilton@gmail.com.

The opportunity to reduce winter feed costs

Harvesting feed with a cow is much less expensive than harvesting, hauling, storing and feeding it with machinery. Grazing also reduces manure-handling costs because the cows distribute manure and urine directly onto the field.

A University of Nebraska economic example compared grazing corn residue with feeding hay to cows. With cornstalk rent at $30 per acre and about 2 acres allocated per cow, the residue cost was about $0.49 per cow per day. In the same example, brome hay priced at $165 per ton cost approximately $4.71 per cow per day after accounting for feeding waste, fuel and labor.

Grazing corn crop residue for 60 days will save $252 per cow vs. feeding hay for 60 days. In a 40-cow herd, that is a savings of $10,080. Would that help your bottom line?

What about soil compaction?

The concern is understandable. A mature beef cow places considerable weight on a relatively small hoof area, and hoofprints are particularly visible when the soil is wet. However, visible hoofprints or surface roughness do not necessarily mean that the soil has been compacted deeply enough to restrict root growth or reduce yield.

In a 16-year University of Nebraska study, corn residue was grazed during either the fall or spring in a no-till corn–soybean rotation on silt-clay-loam soil. Researchers found:

- No detrimental change in soil bulk density

- No meaningful reduction in soil nutrients

- No reduction in subsequent corn or soybean yields

Fall grazing did not increase soil compaction. Spring grazing produced some, but it remained below the level expected to restrict root growth and did not reduce crop yield.

A more recent Nebraska experiment deliberately tested a difficult situation: cattle grazed thawed spring soil at either three cows per acre for 45 days or nine cows per acre for 15 days. Some minor compaction and surface roughness occurred, and planting required slightly more down pressure and slower travel. Nevertheless, subsequent soybean yield was not reduced and was actually improved in the grazed treatments.

Therefore, it is more accurate to say that properly managed corn-residue grazing does not cause agronomically important compaction. Risk increases when cattle are concentrated for extended periods on thawed, saturated soil – especially around water, mineral feeders, and windbreaks.

Practical suggestions include:

- Turn cattle in when soils are mostly dry or frozen

- Avoid concentrating cattle in one small area

- Move water and mineral locations when practical

- Remove cattle during prolonged muddy conditions

Minor surface effects commonly disappear through subsequent freezing and thawing, tillage or normal seedbed preparation.

Grazing manages “trash” without removing all soil cover

Plant populations in corn fields have increased dramatically over the past 20 years. High-yielding corn can leave a thick mat of residue. That residue protects the soil from erosion, reduces evaporation and contributes organic matter, but excessive residue can also interfere with planter performance, seed placement and early soil warming.

Cows primarily remove or break down the leaves and husks – the material many producers call “trash” – while leaving most stalks, cobs and root crowns. Some residue is consumed, some is trampled into contact with the soil, and some is returned as manure.

Cattle retain very little of the nitrogen, phosphorus and potassium they consume while in midgestation. Most nutrients are returned to the field in manure and urine. Grazing may also accelerate nutrient cycling by reducing residue particle size and increasing residue contact with the soil.

Many farmers with sizeable corn crop acres can also bale the crop residue for feed or bedding. Agronomists advise producers to let the combine make a “windrow” of the residue and bale it. This allows you to leave the stalks, cobs and some leaves as residue to protect the soil from erosion. These bales contain nutrients that are now being removed from the field, and appropriate fertilization should be considered.

Fields subject to severe erosion, low-residue fields, and steep slopes are not appropriate for grazing. Enough cover must remain to protect the soil. View grazing as controlled residue management, not an attempt to strip the field bare.

Can grazing help the soil warm earlier?

A heavy surface-residue layer reflects sunlight and insulates the soil. University of Nebraska crop research consistently shows that soils covered with corn residue warm more slowly in spring than soils with less residue.

By consuming and breaking up some of the leaves and husks, cattle expose more of the soil surface to solar radiation. This can increase spring soil warming, help the surface dry sooner, improve planter operation and seed placement, and create more opportunities for earlier planting.

Grazing is a way to manage excessive residue that can delay soil warming and interfere with early planting.

 

What happened to crop yields after grazing?

The most reassuring evidence comes from experiments that directly compared grazed and ungrazed areas.

Study and cropping system Grazed yield Ungrazed yield Interpretation

16-year eastern Nebraska corn-soybean rotation, soybeans following fall grazing Approximately 3.4 bu./acre greater Baseline control Grazing significantly improved soybean yield

Five-year western Nebraska continuous corn 154 bu./acre 148 bu./acre No real difference

Three-year study at three continuous-corn locations 239 bu./acre 223 bu./acre Slight advantage to grazed

Three-year study at two corn-soybean locations 59 bu./acre soybeans 62 bu./acre soybeans No real difference

The conclusion is that grazing at recommended rates did not reduce subsequent yield, and long-term fall grazing produced a modest soybean-yield benefit in one study.

The soybean response may have resulted from improved seed placement, warmer spring soil, faster nutrient cycling or greater soil microbial activity. Researchers have also documented increased microbial biomass in grazed areas, and improving soil health is always a priority.

I work with a beef producer who has many of his “crop-only” neighbors call him to ask if he will bring his cows to their farm to graze their stalks. They mostly do it to reduce the amount of “trash” in the field so they can plant earlier the following year, but they also appreciate the cows cleaning up the fence rows and any waterways.

A practical win for a beef and crop farm

Corn-residue grazing allows you to harvest two products from the same acreage: grain through the combine and winter feed through the cow. When properly managed, it can:

- Replace a substantial amount of harvested hay

- Reduce feeding, machinery, fuel and manure-handling costs

- Rest perennial pastures

- Return most consumed nutrients to the field

- Reduce excessive leaves and husks

- Improve planter performance in heavy residue

- Encourage faster spring soil warming

- Maintain – and occasionally improve – the following crop’s yield

The best results come from moderate stocking, close observation of cow condition, protection of vulnerable soils and timely removal of cattle when the desirable residue has been consumed or fields become excessively muddy.

For the producer who owns both the cows and cropland, cornstalk grazing is not merely a way to dispose of residue. It is a second harvest – one that can lower cow costs without sacrificing next year’s crop.