Harvest losses can significantly reduce soybean growers’ yields and profitability. Harvest losses of 12% can easily occur if combine operators don’t pay close attention to equipment adjustments and operation. Michigan State University (MSU) Extension Educator Mike Staton suggests that adopting a few harvest-management strategies can limit losses to 3% or less.

“Shatter losses at the header account for most of the harvest losses,” says Staton, who is based in Van Buren County and also coordinates the Soybean 2010 program. “The best way to prevent shatter losses is to harvest as much of your crop as possible before the moisture level in the beans falls below 13%. When soybeans undergo repeated wetting and drying cycles after initially drying below 13% moisture, the pods become brittle and shatter easily.”

In a study conducted at Pennsylvania State University by Interim Grain Specialist Del Voight, a yield loss of 20 bu./acre occurred when harvest was delayed by three weeks. Voight also measured preharvest losses of 12% due to premature shattering when harvest was delayed by three weeks in another field.

He recommends harvesting soybeans one week after 95% of the leaves turn brown, even though some green leaves may still remain on the stalks. Staton suggests that farmers incorporate the following recommendations to limit harvest loss and market more of their 2008 soybean crop:

  • Begin harvesting when the moisture level in the beans reaches 15%.
  • Keep knife sections sharp and tight, and make sure that all guards, wear plates and hold-down clips are in good condition and properly adjusted. Consider replacing standard knife sections with narrow knife sections to reduce shatter losses.
  • Operate the cutter bar as close to the ground as possible.
  • Keep the ground speed at 3 mph or less.
  • Adjust the reel to run about 25% faster than the ground speed.
  • If the crop is standing well, position the reel axis 6-9 in. ahead of the cutter bar and adjust the reel height so that the tips of the fingers operate about 12 in. above the ground. If the plants are tangled or lodged, position the reel axis 9-12 in. ahead of the cutter bar and adjust the height so that the reel runs about 1 in. above the ground. Raise the reel if plants are riding over the top of it.
  • Take advantage of conditions that create damp pods – such as dew, light rains or high humidity – to reduce shattering.
  • Maintain the slowest cylinder speed possible that produces complete threshing.
  • Check header losses periodically by backing the combine up 10 ft. and counting the number of beans per square foot on the ground in front of the header. Remember that you are losing 1 bu./acre for every four beans square foot you find on the ground.

Additional information on reducing and measuring harvest losses is available online at web1.msue.msu.edu/soybean2010/.

For more information about improving Michigan’s soybean crop, visit the Soybean 2010 Web page. Soybean 2010 was developed to help Michigan growers increase soybean yields and farm profitability by 2010. Funding is provided by MSU Extension, Project GREEEN (Generating Research and Extension to meet Economic and Environmental Needs plant industry initiative at MSU and the Michigan Soybean Promotion Committee.