Optimizing combine performance often requires Sherlock Holmes-type detective work. Cracked or chipped kernels in the grain tank might actually originate 10' in front of the driver’s seat, and grain lying on the ground after a pass might have never seen the inside of the machine.
“You can adjust your combine’s rotor speed, concave settings, cleaning fan speed and sieves all day long, and it won’t fix grain damage or grain loss problems at the header,” says Brent Kvasnicka, senior marketing product specialist for combines at AGCO North America.
The first step to minimize grain loss at the corn head is to match deck plate clearances to stalk size. All deck plates, fixed or variable, should be gapped about ¼" wider at the rear than at the front. Initially set hydraulically adjustable deck plates halfway between their minimum and maximum opening, then let the crop tell you how to fine-tune the setting.
“If you see a lot of butt shelling and strings of kernels in the rows right behind the head, the deck plates are likely too wide,” says Matt Badding, John Deere tactical marketing manager for harvest equipment. “If you tighten them too much you might see cut-off stalks and more trash. Balance the deck plate setting to minimize butt shelling without cutting off stalks.”
Whole stalks and trash moving into the machine is a sign of extreme gathering chain/stalk roll speed. “Extra residue makes it harder for the grain to sift down through the trash and risks carrying some of that grain out the back,” says Jeff Gray, Claas Lexion product coordinator. “Minimizing the amount of trash going into the feeder house generally minimizes the amount of grain going out the back.”
Damaged grain in the grain tank leads many combine operators to mistakenly adjust concave settings and threshing speed. Adjusting internal combine settings does little to reduce grain damage if that damage originated at the corn head.
“Even if you’re not actually butt shelling at the deck plates, if you’re running the (stalk) rolls too fast, it can slightly crack the kernels when they smack down against those deck plates,” says Kelly Kravig, Case IH harvest marketing manager “Then when the ears get into the combine, those cracked kernels go ahead and shatter in the rotor, even though the rotor isn’t the cause of the damage.”
Corn head augers are another potential source of grain damage. The height of the auger off the floor of the corn head is critical. Badding advocates setting augers so their flighting grabs all ears.
“What you don’t want is the auger flighting so high it pinches ears against the trough and scrapes off the tips or cracks kernels,” he says. “If you’re getting tipped kernels in the grain tank, check the auger height before you make adjustments to the concave clearance.”
Modern corn heads offer stalk chopping or processing options but there are costs associated. “Those heads are designed to process stalks, but you have to balance the power requirements of shredding stalks into confetti, along with how it can degrade threshing and separation, if you feed extra material through the machine,” Badding says. “Setting a corn head has a major influence not only on grain quality and grain loss, but on the condition it leaves the stalks and residue.”