Corn School: How to reduce mechanical kernel damage


Mechanically harvesting, drying and handling grain corn can compromise quality and take a bite out of a grower’s bottom line.

Earlier this fall, OMAFRA crop systems and environment engineer James Dyck worked with Dietrich Farms of Lucan, Ontario to study mechanical breakage – the impact it has on dockage and what growers can do to reduce that loss. He says it’s important to recognize that broken or damaged kernels large enough to clear a screening test are not recorded as dockage. However, theses kernels are more likely to break down further during drying, handling, storage and transportation.

In this episode of RealAgriculture Corn School, Dyck explains his study indicates growers can see total damage of 20 to 30 percent, including fines, cracks and broken kernels coming straight out of the combine. And that number can rise dramatically during drying and storage. The problem is further amplified in a year like 2017 when many growers are harvesting corn at high moisture and low test weights.

There are steps, however, that growers can take to minimize both the quality and financial impacts of mechanical damage. The first step is to effectively set up and manage the combine to ensure grain is heading to the dryer in top shape. “The number one job is to get those kernels off the cob and also minimize the amount of grind and extra threshing that the machine is going to have to do,” notes Dyck.

When the grain heads to the dryer, growers need to exercise patience, says Dyck. “You may have two percent fines going into the dryer, but you may have five or six percent coming out.” The same thing can happen with breakage where 20 percent broken kernels entering the dryer can become 40 percent coming out.

“The trick here is to watch your plenum temperature,” explains Dyck. A lower plenum temperature will slow throughput but it does pay off. “If you do it properly, your test weight is actually going to increase as you dry… sometimes you can even turn Grade 3 corn into Grade 2 just by drying it a little more slowly.”

Once grain is in storage, it’s important to manage movement. Dyck recommends coring out bins to manage fines but unnecessary movement should be avoided. “Aerate it, keep it in good condition, but move it as little as possible to prevent that mechanical damage. Then you know you are going to have a better-quality product when you finally ship it out.”

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