Corn Head Tune-Up

August 26, 2011 08:07 PM
Corn Head Tune-Up

Thicker cornstalks and higher populations mandate careful adjustments of corn heads to minimize losses

Planting new varieties and higher populations means more ears in the field. But if your combine header isn’t prepped to handle the additional stalks, which are often thicker and tougher, those extra ears might not make it into the hopper.

Deck spacing is one of the first header components to tweak.

"If the average cornstalk in a field measures 1" [in diameter], I want my deck plate spacing at 11⁄8"," says Jeff Gray, senior product specialist for Claas Lexion. "Too wide and you get butt shelling. Too narrow and it tends to strip leaves off, maybe break off the upper stalk, which overloads the separator with excess trash and makes it harder for the combine to separate grain from trash back on the sieves."

Steve Luther, assistant farm manger for Stine Seed Farm, Adel, Iowa, oversees five combines that harvest more than 10,000 acres each year. He, too, is meticulous about deck plate tweaks.
"Between being able to adjust the spacing of the deck plates on-the-go and the beveled inner edges on the deck plates, we’ve reduced grain loss at the corn head significantly," he says.

Focus on the grain. Operating the chains and stalk rolls of a corn head at high speeds can also contribute to overloading combine sieves with material other than grain (MOG).

"If you have corn with a lot of green stalks and leaves, you don’t want a fast header speed," says Kent Hawk, combine specialist with John Deere. "Slower backshaft speeds keep more MOG out of the machine."

The amount of MOG ingested by corn heads is also influenced by the groundspeed of the combine. Stalks should move vertically as they’re pulled down through stalk rolls. Stalks leaning forward before getting pulled down imply the groundspeed is too fast in relation to header speed. Stalks that zip violently through the rolls before they are barely between the deck plates indicate groundspeed is too slow or header speed is too fast.

Slower groundspeeds allow slower header speeds, which can reduce grain loss and MOG intake.
"We rarely run our combines faster than 4 mph when we’re combining corn," Luther says. "We could run faster, even with 16-row heads because the machines can handle it, but we’ve found our best grain quality and minimum grain losses come at 4 mph."

Some farmers use their corn heads for more than harvesting corn. By running corn heads low to the ground at the fastest possible header speed, they attempt to mangle cornstalks to make them less prone to plugging tillage tools. Hawk discourages farmers from using corn heads as stalk choppers.

"You limit the capacity of your combine if you try to chop stalks with a corn head that isn’t equipped with special chopping units," he says. "Any stalk processing you get from a combine should be secondary to doing the best job possible of threshing and separating the grain."

On point. Mechanical adjustments and speed are the basics of optimum header performance, Gray says, but auto-steer systems are also proven grain savers.

"The initial thought was that autosteer systems would relieve stress on drivers, but we’ve found that having the stalks feeding precisely into the center of the stalk rolls actually reduces grain loss," he says. "We don’t see stalks bending sideways then flipping ears because the operator isn’t driving exactly centered on the row.

"If the corn is goosenecked or lodged, mechanical row-sensing sensors that ‘feel’ the stalks with sensing wands do a good job of finding the base of the stalks and keeping the combines on the row, which dramatically reduces grain losses."

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