Keep that corn head calibrated to prevent yield loss, disease
If your combine's leaving corn on the ground in your fields this fall, you're doing more than just losing yield. You may be creating ideal conditions for a disease that's run rampant through fields around the Midwest this year.
In this year's corn fields that will become next year's soybean fields, corn kernels left on the ground this year could help sudden death syndrome (SDS) get a head-start next year, says one ag engineer.
"Leaving corn in the field during harvest always results in a yield penalty. A recent soybean SDS article shows data that suggest corn kernels may be one of the most likely sites for survival of SDS pathogens with potential to harm subsequent soybean crop," says Iowa State University (ISU) ag engineer Mark Hanna.
Minimize that possibility by keeping your corn head calibrated for the field conditions you're encountering, Hanna says. That means in-field checks for both ears and kernels.
"Be particularly aware of dropped ears as hundreds of kernels are lost in a single ear drop. Finding just one ear by kicking through residue in a 20 x 22 foot area behind an 8-row cornhead equals one bushel per acre loss," Hanna says. "Ear-saver tabs or shields commonly found at the lower end of stalk rolls should be maintained and excessive harvest speeds avoided to keep ear losses down."
Check the deck or snapping plates that shield the stalk rolls and adjust them according to the ear size in the field you're running, Hanna adds. Kernels can typically be left in the field when you're shelling corn "when the butt end of the ear is allowed to contact stalk roll.
"A good starting point for today's corn hybrids is about 1 1/4-inch gap between plates to allow stalks to move through between deck plates, but ears to be snapped before contacting stalk rolls," he says. "It may be advantageous to allow a slightly wider gap at the top/rear of plates so that stalks don't wedge."
On newer machines, that gap between deck plates can be hydraulically adjusted from the cab, eliminating the need to manually adjust between fields. That being the case, Hanna says the best way to check is by stepping into the field every now and then.
"Take a few minutes periodically to check and measure losses on the ground. Perhaps disease pathogen survival offers another reason to limit corn loss in the field this fall," he says.