Accounting for Harvest Loss
An acceptable loss of harvest for both corn and soybeans should be one bushel or less per acre. It only takes two kernels of corn or four soybeans per square foot to make a bushel of grain.
Ensure Equipment is Harvest-Ready
- After the combine is all greased up, turn on the separator and head for 15 minutes and check all bearings to make sure they cool. Any bearing that is heating up isn’t going to last long out in the field.
- Check the belts and chains to ensure they are running straight and true. Properly tensioned chains shouldn’t have a lot of slap in them as they are running. Belts should not be running in the very bottom of the V of the pulley, and belts with frayed parts should be replaced.
Create a 10 sq. ft. area by attaching a 22 ft. piece of string or twine to four rods, such as fence posts. This simple tool can be used to check for loss of grain per row in the corn head or in the separator tailing.
- Preharvest loss: After the field is opened up and the end rows are complete, disengage the straw chopper and spreader and open it up, if possible, so the straw isn’t spread across a wide area. Harvest into the crop about 300 feet to make sure everything is running to capacity. Then stop, raise the head and let it clean out. Mark where the front tire of the combine is, shut off the separator and back the combine out of the way. Go into the unharvested grain and look for how much preharvest loss you have prior to the combine running through.
- Header loss: For corn heads, use the string and rod tool you made to check each of the rows for harvest loss just ahead of the front wheel and compare them to each other. For soybeans, use your tool to check the entire head, noting any areas with additional loss. Remember, 20 kernels of corn or 40 beans per 10 sq. ft. equal one bushel of loss.
- Separator loss: Behind the combine where the stalks are dumped out, use your tool to check for separator loss. Count the loose kernels and improperly thrashed corn on cobs or soybeans still in pods.
- Harvest loss = (header loss + separator loss) – preharvest loss
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