Combine Settings for Harvesting Drought-Stressed Corn

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  • This summer and fall, growers will be harvesting one of the most drought-stressed corn crops on record. Many growth abnormalities can be seen in fields today, requiring special considerations to mitigate harvest challenges.
  • The following comments are applicable to combines from most manufacturers; exceptions will be otherwise noted.
  • Consult your local dealer for information pertaining to your own make and model.
  • Safety first. With the extremely dry conditions the risk of combine fires is very real. Keep an eye on the combine engine compartment and be sure all fire extinguishers are charged and accessible every time you harvest.
  • Most of the large capacity machines used today are designed to operate at peak efficiency with a "full load." Separation is better, grain quality is higher, and grain samples are cleaner. Keeping a “full load” on the machine this fall will be a challenge.
  • Higher ground speed will be a good thing. This will help keep the machine full.
  • Gathering chains will need to match ground speed. If stalks are leaning in the direction of combine travel, speed up gathering chains.
  • Removing as much trash as possible at the head will be beneficial but will also be a challenge.
  • Deck plate spacing: 3/4" in the front, 7/8" in the back will help remove trash at the head. Operators with hydraulic deck plates can adjust accordingly.
Deck plate spacing
  • Concaves: adjust tighter than normal based on cob size. Measure cob diameter to set and adjust (hand shell what you think will be an “average” size cob).
  • Rotor: set at perhaps 150 to 200 rpm slower than the minimum setting in the operator's manual. Spongy cobs will break easily. Keep material in rotor longer and handle as gently as possible.
  • Chaffer: hand shell what you think are “average-sized” ears and throw grain onto chaffer. Set accordingly – if one or two kernels are laying on top, that's probably a good thing.
  • Sieves: tighter – adjust to tailings.
  • Fan speed: minimum of 50 to 70 rpm lower than normal, or perhaps even lower
  • Feed accelerator/feeder house chains: run at normal speed. **Additional note on John Deere machines: grates on tine separating section – leave bushings out.
  • Do a Full Shut Down. Harvest 100 yards, stop, and check for grain loss and cob diameter (largest to smallest). Adjust settings as needed. Stalks cut off in snapping rolls should be less than 3/4 length. Equipment dealers point out that doing a full shut down is the best way to see how the machine is performing.
  • Remember: every time field work is done, it affects what’s done the next time we are in that field. These recommendations are not only to maximize harvest but to minimize field loss that results in volunteer corn in next year’s crop.
  • Harvest safely.

Thanks to Dennis Payne of McLean Implement in Albion, Ill., and John Aubin of John Deere Company for their input on this article.