Alabama Corn: Harvest Considerations for High Moisture Fields

Corn harvest in Alabama perplexes many not familiar with the process. Harvesting field-dried corn doesn’t seem like the right course of action, often drawing many questions from the general public.

An Alabama Extension agronomist based in the Wiregrass is suggesting farmers consider harvesting corn before it dries down in the field to minimize harvest losses and economical impact.

Harvesting High Moisture Corn

Regional agronomist Brandon Dillard said farmers may want to harvest high moisture corn to reduce the risk of storm impacts (i.e., high winds, straight-line winds, tropical storms), lodging, ear drop or grain shattering.

The longer the stalks stay in the field, the more likely ears will drop below the header and cause substantial losses over the course of a large field.

“It only takes one ear per 100 feet of row to equal one bushel per acre, or two kernels per square foot to equal one bushel per acre,” Dillard said. “If you are shattering corn in the header and losing kernels in the combine it doesn’t take long to lose five to 10 bushels per acre.”

He said any time farmers can work to limit those losses, it is worth the work.

Harvest Early to Increase Efficiency

Farmers also harvest high moisture corn to increase combine efficiency. Dillard said research has shown combines are at peak efficiency when harvested grain has a moisture content of 20 to 22 percent. At this moisture level, harvest losses can be as low as 2 to 5 percent while field dried corn losses can be anywhere from 8 to 10 percent.

To be most efficient, corn should be harvested at 15 percent or higher. Dillard said harvesting with a moisture content lower than that increases harvest losses.

“Corn farmers should plan harvest so that they end the year harvesting around 15 percent to be at max harvesting efficiency,” he said. “While this can be difficult because it seems much easier to put the corn straight into a bin or load onto a semi-truck, being efficient in the field will pay in the end.”

Harvest Early to Double Crop

Planting a second crop is another draw toward harvesting a high moisture corn crop.

South of Montgomery, several producers have successfully planted corn after a successful corn crop. The first crop yielded 250+ bushels per acre; the second crop yielded 180 bushels per acre.

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“During this particular year we had a long fall,” Dillard said. “The farmer harvested the first crop around July 1 at a moisture content of 30 percent, and planted the second corn crop by July 15.”

More commonly, farmers plant double crop soybeans after corn harvest especially under irrigation. This option allows farmers to wait longer to harvest the corn—closer to the end of July—and plant soybeans by Aug. 10.

“Double cropping soybeans is not like planting regular soybeans,” Dillard said. “Producers will need to ramp up the seeding rate. Ideally, the rate should be almost doubled—225,000 seeds per acre on 7.5-inch rows.”

Planting in closer rows allows beans to gain height. Once sprouted, farmers should apply 20 to 30 pounds of nitrogen for the needed boost.

“During the last two years, we have seen farmers produce 30 t0 50 bushel beans behind corn,” he said. “Last year, poor harvest weather reduced the quality of the beans but the yield was still there.”

When to Harvest Corn

Black layer is when corn reaches physiological maturity, which is around 30 percent moisture. After this stage, corn could be harvested and dried in the bin.

“Black layer is when physiological maturity is reached in the grain,” he said. “No longer is that kernel of corn taking nutrients/water or communicating in any way with the cob or the plant.”

Corn will generally average drying at a rate of 0.6 percent per day after this point.

Economical Aspects of Harvesting High Moisture

Dillard said it is important to consider the economics of harvesting early. He said harvest losses generally cost farmers more than the cost of drying, assuming the drying cost remains $0.21 per bushel.

A low harvest loss of 2 percent on 200-bushel corn equals about four bushels of loss per acre—approximately $20 an acre in harvest loss. To dry the corn down, it costs approximately $42 per acre. Combined, farmers are looking at about $62 an acre.

A high-level harvest loss of 8 percent on 200-bushel corn equals about $80 loss per acre. Not including the weight that farmers are giving up by not selling at or near the desired moisture the market is wanting, you can see that losses from harvesting field dried corn can get expensive. These numbers do not include corn quality and weather issues.

“There is a cost associated with drying in the field that may not come out of the checkbook, but definitely comes out of the farmer’s pocket,” Dillard said.

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