The issue becomes, how should the combine be operated, to gather the most ears into the feeder house. University of Missouri researchers suggests these points:

  • Run the combine engine at its rated engine speed.
  • Use a ground speed of 2.8-3.0 mph. (Do not regulate ground speed by reducing engine speed.) To determine ground speed, count how many 3-ft. steps you can take in 20 seconds while walking beside the machine. Divide this number by 10 to get the ground speed in miles per hour.
  • Close the stripper plates or snapping bars only enough to prevent ears from passing through.
  • The chain flights over the stripper plates should extend beyond the edge of the plates about 1/4 in.
  • Ears should be snapped near the upper third of the snapping roll.
  • Drive accurately on matched rows, spaced according to your harvesting machine.
  • Gathering snouts should float on the ground, and gathering chains should be just above the ground.
  • Measure losses and make corrective machine adjustments whenever crop conditions change.

At Iowa State University, ag engineer Mark Hanna says determine where the problem areas are and harvest those first, and he says weak stalks would take precedence over corn that is already near the ground. He suggests measuring your initial losses, so you have a baseline from which to make further combine adjustments. Each ear per 436 square feet equals a loss of 1 bu./acre.

Hanna’s recommendations for combine operation to reduce losses include:

  • Set gathering chains for more aggressive operation with points opposite each other and relatively closer together. Adjust deck plates over snapping rolls only slightly wider than cornstalks so that they hold stalks but not so narrow that stalks wedge between the plates.
  • Operate the head as low as practical without picking up rocks or significant amounts of soil.
  • Single-direction harvesting against the grain of leaning stalks may help. Evaluate losses though before spending large amounts of time dead-heading through the field.
  • Limited field measurements suggest a corn reel may or may not help limit machine losses; however, a reel likely allows greater travel speed and improves productivity. Losses may be similar comparing harvest at 1 mph without a reel and 3 mph with a reel, but harvest goes much faster. Spiral cones mounted atop row dividers or the addition of higher dividers on each end of the cornhead are other potential after-market harvest aids.
  • If harvest speeds are significantly reduced, the amount of material going through the combine is reduced. Fan speed may need to be reduced to avoid blowing kernels out of the combine. Rotor speed may need to be reduced to maintain grain quality. Check kernel losses behind the combine and grain quality to fine tune cleaning and threshing adjustments.
  • Grain platforms have been used to harvest corn in relatively severe cases. More cornstalks and material other than grain enters the combine. Expect capacity to be reduced somewhat. Concave clearance may need to be increased for increased throughput and fan speed may need to be increased to aid separation in the cleaning shoe.



The 2011 harvest season may be as difficult as the planting and growing season. Many farmers will face fields with heavily lodged corn, others with stalks that will disintegrate as they hit the gathering chains. It is important to proceed slowly, making adjustments as the crop changes and realizing that some grain will be left on the ground. It will take a strong will to get through a challenging harvest, and everyone from the combine operator to the truck driver will have to have the right mental attitude.


Read the article at farmgate blog.