CORN RESIDUE LEFT AFTER HARVEST GOOD FOR WINTER GRAZING: U.S. STUDY

Corn residue left after harvest should be a great source of winter grazing, a study by the University of Kentucky says, and considers the residue one of the most underutilized resources in American agriculture.

Writing for the US trade publication Modern Farmer, Dan Nosowitz said the study found out that each bushel of corn produced leaves about 50 pounds of residue. This stuff is generally called corn residue, and it includes the stalk, leaves, cob, and some fallen ears of corn.

Much of this residue is collected and disposed of; some farmers leave it to prevent erosion and inject some more nutrients into the soil over the winter. But there’s another option, and according to a new study, it’s a dramatically under-used one: Let cattle graze this residue.

Morgan Grabau, at the American Society of Agronomy, took a closer look at the idea of cattle grazing on corn residue in a new study. This tactic is not commonly used. “Only 15 percent of the corn residue acres in the central US are grazed,” she says.

There are multiple reasons for that: some corn acreage isn’t close enough to cattle for it to make sense, for example. But there’s also a suspicion held by many farmers that it’s bad for yields, owing to the compaction the cattle will leave in the soil. This turns out not to be the case, the study finds.

The study looked at cattle grazing on corn residue both in winter, when the ground is very hard and resistant to compaction, and in spring, when rains have made it softer. They specifically examined acreage in a corn-soybean cycle, meaning soybeans would be planted following a corn crop.

The research found that there was some compaction, especially in the spring, but that farmers shouldn’t be concerned about it. The compaction was limited to exclusively the very top layer of the soil, and was not permanent.

More important, the next crop of soybeans had “no problem” establishing seedlings in land the cattle had grazed.

Interestingly, the study did not find that there was no difference between land grazed by cattle and land not grazed by cattle—but the difference actually favors grazing. Yields actually increased in soybean fields that had a concentrated 15-day grazing period, which Grabau theorizes may have been due to the cattle removing excess corn residue.

With less residue covering the ground, warmer spring weather could raise the temperature of the soil more efficiently, encouraging early growth.

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