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Drying soybeans artificially

Article cover photo
The safest method to dry soybeans is while they are in the field, but drying them artificially is possible under proper conditions. (Photo: Joseph L. Murphy/Iowa Soybean Association)

By Scott Nelson, ISA On-Farm Network® Director

Late September and early October have been exceptionally wet and have delayed soybean harvest. Some farmers may be contemplating harvesting their soybeans earlier at higher moisture levels to expedite harvest when field conditions are acceptable.

Soybeans can usually be harvested up to 18 percent moisture but must be artificially dried to the appropriate storage moisture of 13 percent. Most driers designed for drying corn can be adapted to dry soybeans. However, drying soybeans can be very risky in terms of maintaining quality and avoiding dockage from splits.

The safest method to dry soybeans in the bin is to use natural air, but it can take a long time to dry wet beans to reach 13 percent storage moisture. The exact amount of time it takes depends upon air temperatures and humidity, usually between two to six weeks.

In extreme cases, some farmers have been able to safely dry soybeans with low temperature heat. This can be risky; beans should be monitored closely. The air should not be heated more than 3 to 5 degrees Fahrenheit.

Finally, it’s important to remember that soybeans can dry rapidly on their own in the field. Under good drying conditions, soybeans can lose about 3 percent moisture per day. This is five times faster than the rate of corn dry-down. Hopefully, most farmers can avoid having to dry soybeans in the bin if the weather allows for a few days of field drying.

Notes from the agronomists

Brett McArtor, ISA field agronomist for southeast Iowa, has seen soybeans coming out averaging 15 percent moisture. Agronomist for northwest Iowa Matt Hoffman noticed beans harvested at 11 percent two weeks ago before the rains moved in.

Both agronomists know that it is a difficult time to get into the field. McArtor says, “short of getting the combine stuck, go when you can.” Both said the rain is hard on crop quality. 

But Hoffman cautions farmers on entering the fields too soon. “The smearing, compaction and ruts caused from entering fields that are too wet will have effects the following year,” he said.

McArtor also reminds farmers that the recommended planting dates for winter-hardy cover crops are approaching. The Natural Resources Conservation Service (NRCS) guidelines are Oct. 21 for northern Iowa, Oct. 28 for central Iowa and Nov. 5 for the southern three tiers of counties.

 Scott Nelson can be reached at

For media inquiries, please contact Katie Johnson, ISA Public Relations Manager at or Aaron Putze, ISA Communications Director at

For permission to republish articles or to request high-res photos contact Aaron Putze at Iowa Soybean Association | 1255 SW Prairie Trail Pkwy | Ankeny | IA | 50023 | US

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