Halt harvest losses
Remember Where's Waldo? He's the red-stripe shirt and bobble-hat cartoon character that kids (and adults) try to find amid dozens of people doing dozens of activities. You don't have to find a newspaper comics to play that search game; you can play it in some harvested cornfields.
In the photograph above, at first glance, a couple corn ears are visible. But a closer look reveals several husk-hidden ears of corn.
These stray ears following harvest cost farmers a couple ways. Kernels on every ear left in the field are less kernels you have to sell. Leftover kernels that convert to volunteer corn can haunt you the following year.
In soybeans, herbicides exist to knock out volunteer corn, but volunteer corn in corn is a particularly vexing problem. And if you plan to plant soybeans the following year, Sudden Death Syndrome could result. Leftover corn kernels are linked with an increased rate of SDS.
That's why farmers should aim for corn harvest losses of less than 1 bushel per acre, says Mark Hanna, Iowa State University Extension agricultural engineer. “If the crop is standing reasonably well, that's obtainable,” he says.
How to detect losses
To assess kernel losses, mark off 10 square-foot areas centered over each row behind the combine. For 30-inch rows, for example, this would be a 4-foot × 30-inch-wide area over the 30-inch row. Searching individual rows allows misadjusted single corn head row units to be detected. An average of two kernels per square foot translates into a 1-bushel-per-acre loss.
To assess ear losses, mark off a larger area, such as 436 square feet (1/100 of an acre). Ear losses add up quickly. In such an area, one ¾-pound ear will equal 1-bushel-per-acre field loss.
“A lost ear can contain 300 to 400 kernels,” says Hanna. Be sure to kick through corn residue to find all lost ears.
Hanna recommends the following steps to cut ear losses.
● Keep ear savers in good condition. “Anything to keep ears from falling out of the cornhead is important,” he says.
● Adjust stalk roll speed to snap ears about one half to two thirds of the way up on the snapping plates. Make sure to properly adjust gathering chains, stalk rollers, and trash knives.
● Adjust snouts so they are just touching the ground.
To slice kernel losses, Hanna recommends four steps.
● Adjust combine snapping plates for ear size.
● Keep snapping plate spacing for average-size ears to 1.25 inches. However, they should be adjusted for conditions. Hanna notes some operators use a .125-inch wider spacing at the rear of plates to avoid stalk wedging.
● Avoid using more rotor/cylinder speed or narrow concave clearance than necessary.
● Use adequate air speed in the cleaning shoe to fluidize the crop to ensure good separation.
Proper combine operation balances between acceptable harvest losses without harming grain quality.
“Today's grain prices are good, but even at lower grain prices, a payback of $50 to $100 per hour is common if you check for losses at harvest,” says Hanna.