Combine Adjustments for Harvesting Lodged Corn

August 21, 2020 2:55 PM
Blog Post

The unprecedented August 10 derecho storm event has caused significant damage to Iowa corn fields. If it’s decided to proceed with harvesting the field for grain, several operational changes may increase performance and productivity of the combine.

  1. Be prepared for slow harvest speed. Communicate those expectations and realities to others. Take frequent breaks, rest, and eat well to help you cope with the added stress. Call Iowa Concern 800-447-1985 to share your concerns or questions.
  2. Harvest lodged corn as soon as practical to minimize additional mold and grain quality loss from ears being close to the ground. Harvesting early will also help ensure the stalks are in the best condition possible to aid in getting crop into the head.
  3. If stalks are lodged across the rows, begin harvesting at the downwind side of the field.
  4. Operate the head as low as possible without picking up excessive rocks and soil.
  5. Flatten the header angle for corn lodged across the rows to allow stalks to rise over the snouts more easily. For corn lodged in the direction of the rows, however, a steeper header angle can help gathering chains lift stalks more aggressively.
  6. Reposition gathering chains on their sprockets so the lugs are directly across from each other to more aggressively grip stalks.
  7. If needed, open the stripper plates slightly to better fit stalk width and use more taper from front to back.
  8. Remove ear saver flaps on each row to allow smoother, more efficient material flow in these down crop conditions.
  9. Lower the tall crop shields at the end of the head.
  10. Consider powered spiral cones mounted atop row dividers at the ends of the head.
  11. If necessary, add weight to poly divider snouts to help them stay under the canopy.
  12. Consider using a corn reel, which may or may not help limit machine losses, but likely allows greater travel speed and improves productivity.
  13. When stalks are lodged with the row, harvesting against the lean may improve gathering. Check actual gathering losses to verify that one-direction harvest improves losses enough to justify the added time investment. Detailed instructions for measuring losses are in Profitable Corn Harvesting. Missed ears will be hard to see under heavy residue. Shuffle your feet through the 1/100 acre check area to find hidden ears.
  14. With slower harvesting, fan speed may need to be reduced to capture most grain while still allowing some poor quality kernels with storability problems to escape. 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.
  15. Plugging is likely to occur more often with these crop conditions. Always completely shut the machine down before leaving the cab and take the key with you to ensure nobody starts the machine without you knowing. Use head cylinder stops when working around or under the head. Catching plugs early often allows reversing the plug out of the head to clear it.
  16. Yield monitor data will be impacted by slow speeds and stop and go harvesting. New calibrations should be done at the typical harvesting speed and header height calibrations verified so the yield monitor registers when the machine is harvesting crop.
  17. Grain platforms can be used to harvest corn in severe cases. Expect capacity to be reduced with more cornstalks entering the combine. 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.

More detail on some of these adjustments is given by Marion Calmer, farmer and president of Calmer Agronomic Research Center, Lynn Center, Illinois in his video presentation from 2015.


Harvest Tips for Lodged Corn, September 6, 2011, ICM News, By Mark Hanna

Combine Adjustments to Reduce Harvest Losses Daniel Humburg, SDSU Extension

Combine Adjustments for Downed Corn, UNL Cropwatch, October 27, 2017


Aaron Saeugling Field Agronomist in SW Iowa

Aaron Saeugling is a field agronomist in southwest Iowa for Iowa State University Extension and Outreach.