It costs money to dry corn – enough so that knowing how much propane it takes to dry down corn at a certain moisture level is worth knowing, according to Mark Hanna, agricultural and biosystems engineering specialist at Iowa State University. Hanna and colleagues have just concluded a two-year case study that investigates drying costs at several moisture levels.
“This case study provides benchmark information to help farmers estimate the propane needed for fall drying,” he says. “For one 80-acre field of corn, those savings can add up to hundreds or even thousands of dollars.”
Moisture levels can severely affect drying costs, Hanna says. For example, when corn was at 23% moisture, it required about 150 gallons of propane per 1,000 bushels. The amount required for 18% moisture was approximately half of that.
Hanna also points to Iowa Crop Improvement Association trials, which show that full-season varieties are about 2.5% higher moisture at harvest than earlier season varieties. That small difference can add up in extra propane costs – to the tune of 38 gallons per 6 acres of harvested corn.
Consider the 10-year average yield of 1u. per acre in Iowa, Hanna says. In that scenario, if propane costs around $2.00 per gallon, drying the higher moisture corn would add up to $12.65 additional expense per acre. That corn would need to yield at least 4 bu. more per acre just to justify the added fuel expense of drying the grain, he says.
Drying data suggest farmers should spread out hybrid maturity so they can potentially take advantage of dry late-season conditions, Hanna says. When fall weather is favorable, it can be advantageous to keep full-season corn in the field longer for additional drying, he says.
Ultimately, Hanna says he hopes farmers will use the case study data to evaluate energy consumption and cost in their own operations.
“Considering that propane makes up such a large proportion of the energy needed for drying, farmers may want to compare their own propane consumption to the measurements for the case study,” he says.
ISU has provided additional information on farm energy efficiency research at http://farmenergy.exnet.iastate.edu.