PRINCETON, Ky. – A University of Kentucky agricultural engineer is recommending producers consider harvesting and mechanically drying corn still left in the field.

“Wet weather and higher energy costs certainly have the potential to squeeze producers’ profits – especially if additional wet weather further delays harvest and losses climb above the average of 5 percent,” said Sam McNeill, extension professor of agricultural engineering at the University of Kentucky College of Agriculture, Food and Environment.

“Even with this season’s high energy prices, most producers could benefit from heated air drying their crop by at least five moisture points,” he added.

He said pre-harvest estimates pegged this year’s corn crop as the largest on record (268 million bushels, with average yields around 185 bushels per acre), but the harvest had a slow start. “One reason was because warm temperatures in early September favored field drying, but another was due to high LP (liquid propane) gas prices,” he said.

As of Oct. 4, he said, corn harvest has progressed to 50 percent complete statewide, which is well behind this time last year and the five-year average (65 percent).

“On a positive note, field drying should have good potential across most of the state for the next week, so many farmers will likely ramp up harvest and benefit from lower drying costs,” he said.

He said this year’s anticipated statewide yield for Kentucky (186 bushels per acre), current price ($5 per bushel), and corn harvest losses (5 percent) amount to $47 per acre. He added that harvest losses can be held to 2 percent by attentive combine operators, few or no weeds and down stalks in the field, and good weather conditions, so the cost of leaving some of the crop in the field can be reduced to $19 per acre if other average conditions hold.

“On the flip side, excessive wind and/or rain, plus weak/down stalks can increase harvest losses to 8 percent, or $74 per acre,” he said.

“Compare these costs to heated air drying, which depends on fuel cost (LP or natural gas), harvest moisture and the energy efficiency of the dryer,” he added. “An average drying efficiency for many new dryers is between 1,500 and 2,000 British thermal units per pound of water, so again I’ll use an average (1,750 British thermal units per pound).”

If LP costs $1.90 per gallon, he said the cost to dry corn to 15 percent moisture from harvest levels of 25 and 20 percent for the drying energy alone would be $54 and $32 per acre, respectively.

“Another $7 per acre can be added to include labor, extra hauling and depreciation on the dryer,” he said. “This range of values is anticipated this season, but producers can use their own values to quickly estimate a meaningful comparison for their operation.”

Returns to drying are calculated for the energy costs alone (assuming the dryer has been paid for) and for ownership costs (which includes drying energy, repairs, labor and hauling costs), he added.

McNeill calculated yields of 150, 200 and 250 bushels per acre by current corn prices of $5 a bushel, and projected harvest losses of 2 percent, 5 percent and 8 percent.

He then compared them to the costs associated with heated air drying the corn by five and 10 moisture points using current energy prices and average dryer efficiency. He found that producers can expect returns from drying the corn at least five moisture points if they anticipate their harvest losses will be 5 percent or greater.

He said gains from drying the crop by five points could range from $6 to $48 per acre, depending on yield when all costs are considered.

“Most operations have average harvest losses,” he said. But, he added, “The value and satisfaction of knowing the crop is safely out of the field depends on individual operations.”

Virgil Schmitt, Iowa State University extension field agronomist, said, in Iowa, in general, very little field drying occurs after about Oct. 10.

“I had one load harvested on Oct. 7, and it’s moisture content was a little over 19 percent,” he said. “The rest of the field was harvested on Tuesday (Oct. 27) and Wednesday (Oct. 28) of this week, and it averaged about 17.5 percent moisture.

“So there is little to be gained by leaving it stand in the field, vulnerable to damage from weather, birds, ear rots, etc.,” he added. “So after about Oct. 10, it is best to harvest it and either sell it wet, and take the moisture discounts, or dry it prior to selling or storing it.”