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.
When it comes to soybeans, many combine operators hope to harvest soybeans at 6 mph with less than 1 bu. per acre of grain loss. Achieving that goal requires careful adjustment and operation of both draper and auger-style grain small grain platforms.
Follow these 11 tips to keep grain loss at a minimum:
■ 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.”
■ Cutterbars are the starting point for optimum performance of both auger and draper platforms. Not only must sickle knives be sharp enough to snag a leather glove, but the rock guards and all wear points must be factory-fresh. Dull sickle sections, or rock guards with rounded edges where the sickle slides back and forth, gnaw rather than slice bean stems. Any vibration to a stem during its harvest can shake loose or shatter pods.
■ The angle of the cutterbar should be parallel to the ground or slightly downhill by 1° to 3°. That angle is determined on older platforms by mechanical adjusters on the bottom, rear of the platform. Newer platforms adjust cutterbar angle by mechanically or hydraulically tilting the entire head. If the angle is too steep, the cutterbar is prone to pick up rocks or gouge the soil. If the angle is such that the platform runs on the rear of its skid shoes, the cutterbar tends to cut stubble higher and drag stems and leaves under damp conditions.
■ Cutterbars must be straight so automatic header height control systems work properly.
“Bent cutterbar supports can create high spots [in a cutterbar] that make it more difficult for the cutterbar to flex and follow ground contours,” Badding says. “Bends in a cutterbar also increase wear to the knife.”
■ Check cutterbars by raising a platform 5' to 6' off the ground. Sight across the cutterbar from one end of the platform. High spots in the cutterbar suggest bent supports or brackets. Diagnosis can be tricky because small irregularities among cutterbar supporting components are magnified by the geometry of those components. A 2" hump in a cutterbar can be the result of only a ¼" bend in a support frame or related component.
■ Older platforms with broad, wide skid shoes flex and follow the ground surface better if the previous year’s crop debris and dirt is cleaned from the tops of the skid shoes. Use compressed air to blow from behind the sickle toward the rear of the skid shoes. Material packed into that pivot point hinders the skid shoes from flexing and following the soil surface.
■ Newer platforms feature an adjustable hydraulic system to control the pressure of the cutterbar against the ground.
If operators increase pressure, more of the weight of the cutterbar is carried by small hydraulic cylinders under the header frame, Kvasnicka says. This makes the cutterbar less heavy and less likely to push in damp or soft soil conditions.
If operators reduce cutterbar pressure, Kvasnicka says less of its weight is supported by the small hydraulic cylinders. The cutterbar becomes heavier but more flexible and better able to follow surface irregularities. The increased weight and contact with the soil surface can lead to pushing
in damp or soft soils, though.
Once basic settings are made, adjustments to the specific platform further optimize performance.
Running an auger platform? Read Dan Anderson's tips on minimizing grain loss.
Using a draper platform? Use these tips to dial in belt speed for even feeding.