Harvest timing, technology keys to corn profitability

Increased corn acreage across the Southeast doesn’t necessarily mean increased profits, especially if growers fail to efficiently harvest their crop.

Using available technology and timing harvest properly can reduce losses and increase profitability.

The first step to insuring harvest efficiency is to be sure harvest equipment is in proper working order. For growers who have not grown corn in some years, and in some cases have never grown corn, checking combine belts for dry rot, replacing worn parts on the picking heads, especially parts like snapping rollers that come into direct contact with corn, can pay off once harvest begins, according to University of Georgia Extension Agricultural Engineer Paul Sumner.

“A corn combine is not that complicated a machine. However, if someone has just bought a used combine and is not familiar with combines, they should probably have someone come in and check the machine to be sure it is in good working order,” Sumner says.

It is also important to be able to make in-field adjustments on the combine. As moisture content of corn in the field changes, it is critical to be able to make changes in clearance in the rotor and the picking mechanism — primarily the concave elements of the combine.

Making adjustments in air flow and rotor, for example, can decrease the amount of harvest loss.

Newer combines may have instruments to help farmers monitor the amount of harvest loss they are getting. If not, the easiest way to monitor harvest loss, Sumner says, is to measure from center to center of the row 3.4 feet and count the number of kernels in that area. If there are more than 20 kernels per 10 square feet, the grower needs to make adjustments to the combine.

Once the amount of harvest loss is determined, the grower needs to determine from which part of the combine the losses are coming. If kernels are adhering to the corn cob, for example, Sumner says, the threshing mechanism is not tight enough or the moisture content is too high.

Harvesting at 22 to 27 percent moisture, there is the least amount of harvest loss. The downside of saving harvest loss is the cost of drying the corn down to the 12 to 14 percent moisture needed to store corn. If a grower has 300 acres of corn, of the same variety, the grower may start combining at 26 percent, but by the time he finishes combining, corn may be down to 15 to 18 percent.

Sumner stresses that on-farm drying capacity must be matched with combine capacity. If a grower starts combining when the dew dries and harvests until dark — 10 to 12 hours — typically the grower will harvest up to 5,000 bushels of corn per day. If the grower doesn’t have that much drying capacity, he will either have to delay harvest or risk damaging the crop by leaving high moisture corn in a truck or temporary facility waiting for the dryer. In reality, in this situation the option is to leave it in the field, Sumner says.

The cost of harvesting an acre of corn, not including purchase and depreciation costs of the combine, is approximately $24 per acre. What happens with the corn after it is combined is sometimes as critical to profit as getting it out of the field.

Sumner says it is critical to keep time on the truck from the field to the elevator or other drying or storage facility to a minimum. If corn yields are average across the Southeast, there is likely to be a major shortage of storage facilities and likely to be long lines waiting to deliver corn.

Keeping corn on a truck for more than six to eight hours in the environmental conditions typical at corn harvest can significantly damage the corn and reduce quality and value, Sumner cautions.

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