Advice for chopping failing corn fields for silage


July 31st, 2012 by Ric Hanson

Iowa livestock farmers who’ve seen their pastures dry up and their hay supply dwindle may be able to find another source to feed their animals. Corn stalks can be chopped up and turned into silage. Daniel Loy, a livestock specialist with Iowa State University’s Extension Service, says the corn stalks must have about 60 to 70 percent moisture and stalks that look dry often have that much moisture inside. “The key to quality harvest of silage is to exclude the oxygen…cover it with plastic or other material so that they can exclude as much oxygen as possible, and then it goes through a fermentation process which is almost exactly like pickling,” Loy says. That pickling process takes about three or four weeks.

“It will develop enough acidity and drop the pH to a level that actually will fight off the microorganisms that might cause it to deteriorate,” Loy says. “It becomes stable at that point and that’s why, if you’ve ever smelled corn silage, it has that sweet/sour aroma which is very much similar to what you would find in your pickle jar.” You can’t just go out in a field and start chopping with a mower, however. It takes special equipment to cut silage. “There are custom operators that will bag silage and put it into a big plastic bag which is kind of a silo-on-the-spot and there are also custom operators that will do the chopping and delivery,” Loy says, “so if producers aren’t really set up to harvest and store silage, there are opportunities for custom operators to help them do that.” But not every corn field that’s judged a total loss for the farmer who wanted to harvest the corn in bushels can be sold as tons of silage.

Some crop insurance policies bar farmers from chopping the corn plants for resale as silage. In other fields the nitrogen content of the corn stalks may be too high to be fed to livestock. But Loy says that four-week process of converting the chopped corn into pickled silage cuts the nitrogen levels. “That can reduce the nitrates that (are) in the plant material by 30 to 80 percent, depending on the quality of the fermentation,” Loy says. “So between diluting with other feed stuffs, between the reduction in nitrate that occurs during the ensiling process, the risk can be decreased quite substantially.” Loy advises farmers to visit with an expert if they’ve never chopped silage before and to check with an advisor before feeding silage to their livestock for the first time. Go to to find a link to I-S-U Extension resources about silage.

(Radio Iowa)