Farmers may want to think twice before selling corn stover
November 6, 2009
LINCOLN, Neb. – While there have been some offers from a couple of energy companies to buy corn stover this year, Nebraska farmers need to take into account the soil structure loss and nutrient loss before making that decision. Corn stover, or the residue left behind after harvesting corn, can be made into pellets and sold to coal burning power plans generating electricity, said Paul Jasa, UNL Extension engineer.
These companies are offering $15 a ton for short term contracts and up to $20 a ton for longer term contracts, typically for 3 tons per acre, Jasa said.
While at first glance this may sound like a lot of money, what is lost in the value of that residue far exceeds what is being offered, Jasa said.
“Our consensus is that they are not offering enough money to give up that corn residue,” Jasa said. “The lost nutrients alone aren’t even covered by the price, let alone the loss in soil structure.”
Corn residue left on the field after harvest contains valuable nutrients that fertilize next year’s crop. The nutrient value of corn residue can range from $17 a ton to $46 a ton. This price range all depends on current fertilizer prices and the differences in nutrient content of the removed residue. The sooner the residue is removed after grain harvest; the more nutrients are removed.
Assuming a residue harvest of 3 tons per acre on an irrigated corn field, this results in a range of $53.79 to $138.51 per acre extra in fertilizer that will be needed to replace the removed nutrients, Jasa said. This will have to be replaced over the long-term to protect productivity, and it doesn’t include the loss of carbon from the soil system as residue is removed, possibly reducing organic matter.
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Removing that residue also increases soil water evaporation and will take away about 3 to 5 inches of soil moisture.
“Residue conserves soil moisture and removing that residue opens up the soil to evaporation,” Jasa said. “On irrigated fields, that is more water that will have to be put on that field, and on dryland fields, that is just moisture lost and reduced yields.”
While Jasa says he isn’t against selling corn stover, he feels that the current price being offered is too low. Jasa said about $50 per ton, not including labor costs, would start to cover the nutrients and some of the moisture that is lost. In addition, producers need to look carefully at the length of the contract so that they aren’t locked into something as prices, production and conditions change, he said.
For more information about harvesting crop residue, visit Crop Watch, UNL Extension’s crop production newsletter, at http://cropwatch.unl.edu/web/cropwatch/archive?articleID=1503245 which also contains additional resources on harvesting crop residue.