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Several factors cause specialists heartburn.

Tom J Bechman 1, Editor, Indiana Prairie Farmer

October 11, 2006

2 Min Read

New work coming out of Tony Vyn's research work at Purdue University shows that air quality levels of carbon dioxide and nitrous oxide, unfriendly gases for the environment, are higher after chiseling corn stalks than after any other tillage system. The difference is pronounced in corn-after-corn situations where nitrogen is applied every year.

But don't stop reading: Vyn says there are more practical reasons that concern him about chisel plowing as well, particularly in corn after corn. "You may be running 8 or 10 inches deep, but you're not burying residue to that depth," he says. His studies show that residue typically mixes to about half the operating depth in chisel-plow systems.

So is that a big deal? Vyn thinks it can be if you're planting corn after corn the next spring. Something called the allelopathic affect that is devastating to alfalfa drilled into existing alfalfa stands, or too soon after an old stand is destroyed, also exists for corn after corn. Decaying corn residue produces substances that make it tougher for new would-be corn seedlings to germinate and grow.

"If you're only mixing to a depth of 4 to 5 inches then that residue is not far from the seed zone when you plant next spring," Vyn says. "That's just a very high level of corn residue very near the seed zone. The potential impact of that situation on next year's corn is enough to cause me concern."

Moldboard plowing tends to bury nearly all of the residue. That's a negative on erosive soils, but on flat soils where soil erosion is not a high risk, it does greatly reduce the threat of having large amounts of decaying corn residue in or near the new seed zone.

Note that these comments apply only for corn after corn. Decaying corn residue would not be expected to have an effect upon germination or emergence and survivability of soybean seedlings if you're rotating to soybeans next year.

And also note that strip-till is an option. It's actually Vyn's preferred option for corn after corn on all but sandy soils. There he would opt for no-till. Strip-till cleans a zone on the surface for planting into next spring, but still leaves a considerable amount of residue on the surface to protect against soil erosion.

About the Author(s)

Tom J Bechman 1

Editor, Indiana Prairie Farmer

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