When Iowa farmers were done harvesting this year’s drought-stunted 2012 corn crop this fall, many of them didn’t stop there.
They returned to the fields to chop and rake the dried cornstalks into round bales that, at first glance, don’t look much different from hay bales.
The material is known as corn stover. Experts say farmers began harvesting more of it in the last few years of rising hay and grain prices, and harvested a lot more of it this year as the 2012 drought drove hay prices to record levels.
Corn stover is different from silage, a livestock feed typically made by chopping up green corn plants and storing the material in a silo for partial fermentation. It’s dry and course, but cattle will eat it, particularly when they have nothing better.
“It’s really not much more than filler,” said Erle Driscoll of Waldrige Farms near Williamsburg, which produces organic corn and breeds Angus cattle.
Driscoll said corn stover doesn’t do much more than satisfy the animal’s appetite unless it’s mixed with other ingredients. Waldrige Farms mixes it with high-quality hay, vitamins and minerals, to stretch the volume of feed from its hay output every year.
Iowa State University Extension Beef Specialist Denise Schwab is among the livestock production experts who are seeing an increase in reliance on corn stover. She said many farmers were using corn stover for livestock bedding, and converting the corn stover into livestock feed adds little complexity to the process.
Farmers need to know the right mix of vitamins and minerals to add to the stover to feed their cattle, Schwab said. They often chop the stover in a tub grinder to make it easier for cattle to digest.
Demand for corn stover is high enough that some livestock producers who don’t grow enough themselves buy it from their neighbors, and it occasionally makes it to hay auctions.
Corn stover typically sells for between $20 and $30 per bale, according to ISU Extension Economist William Edwards, who has researched the direct and indirect costs of producing corn stover. Some has sold for as much as $45 per bale.
Edwards said 2012 was close to perfect for harvesting corn stover because the corn matured much earlier than usual and dried out quickly in the field. That gave farmers plenty of time to go back into the field to harvest the stover, something that might be a challenge with a late-maturing crop.
Although corn stover might seem like a virtually free animal feed, Edwards has shown that it really isn’t.
Processing corn stover is harder on balers and other equipment than harvesting hay, and can require more frequent sharpening of cutting blades. There are fuel and manpower costs to harvest the stover, and the cost of replacing nutrients lost when the stover is not tilled into the soil to decay.
To avoid starving the soil by removing all the stalks, Schwab said farmers typically leave some of the stover in the field or rotate the fields they harvest for stover. Driscoll said nutrient loss isn’t an issue at his farm because he always rotates crops.
ISU Extension Economist Jim Fawcett says keeping corn stover in the fields is becoming less of an issue because modern corn genetics enable the planting of more corn plants per acre. As a result of the higher plant concentrations, he said it’s getting harder for farmers to plant over the corn residue buildup.
The demand for corn stover as livestock feed could be colliding with demand from another source due to interest in corn stover by the emerging cellulosic ethanol industry.
Cellulosic ethanol producers produce the fuel from non-grain vegetation or cellulose such as corn stover, corncobs, grasses, wood chips or even paper waste.
DuPont Industrial Biosciences contracted with 50 corn growers in the area of its planned cellulosic ethanol plant at Nevada to produce corn stover in 2011, and added about 100 more growers to its supplier list in 2012.
The company plans to break ground on what could become Iowa’s first full scale commercial cellulosic ethanol plant at the end of the month.
Schwab said she doesn’t know how cellulosic ethanol demand will affect livestock demand for the corn stover. She expected cellulosic ethanol demand to be concentrated mainly in the immediate vicinity of cellulosic ethanol plants to minimize transportation costs.