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Cool beans: It’s a must for long-term soybean storage

Article cover photo
Charles Hurburgh, a professor of agricultural and biosystems engineering at Iowa State University, says that farmers should be able to safely store soybeans through the winter. (Photo: Joseph L. Murphy/Iowa Soybean Association)

By Matthew Wilde, ISA senior writer


Farmers should be able to safely store soybeans through the winter despite moisture and damage concerns if appropriate actions are taken, according to the state’s foremost grain storage expert.

If producers quickly dry soybeans to 13 percent moisture or less and cool oilseeds to about 30 degrees, Charles Hurburgh said soybean quality can be maintained for months after harvest giving farmers additional marketing options.

Hurburgh, a professor of agricultural and biosystems engineering at Iowa State University and head of the Iowa Grain Quality Initiative, said the recent stretch of dry and warm weather and low dew points not only propelled harvest but improved storability of the crop.

“If farmers cooled and dried soybeans right away, they should get through the winter and possibly beyond to allow for marketing discussions and decisions,” Hurburgh said. “There is a big carry in the market right now.”

Cash soybean bids Wednesday at multiple elevators and processors were about $8 per bushel, give or take 20 cents. May soybeans on the Chicago Board of Trade closed at $9.05 per bushel.

For the more than 1 million acres of soybeans still in the fields, the latest round of rain adds to moisture and damage concerns.

Twelve percent of the soybean crop is yet to be combined, according to Monday’s weekly U.S. Department of Agriculture Iowa Crop Progress and Condition Report. Harvest is 2 days behind last year and six days behind normal.

“Unfortunately, significant rainfall returned to much of the state and likely stalled harvest for several days,” said Iowa Secretary of Agriculture Mike Naig in a statement. “This has been a very challenging fall, and not just to harvest crops.”

Soybean moisture and quality plays a significant role in storage length.

Charles Hurburgh, Department of Agriculture and Biosystems Engineering at Iowa State University, gives tips on storing damaged grain.
Charles Hurburgh, Department of Agriculture and Biosystems Engineering at Iowa State University, gives tips on storing damaged grain.

Much of the earlier harvested soybeans likely exceeded the optimum moisture level of 13 percent, which is a rare occurrence. Some farmers couldn’t wait for soybeans to dry naturally given harvest delays and quality concerns.

Mold, sprouting, pod shattering, splits and disease issues were common this year. Based on field reports and tests, Hurburgh estimates this year’s soybean crop averages 2-3 percent damage statewide. One percent or less is normal, he said.

Grade limits for No. 1 soybeans are 2 percent damage. For No. 2 soybeans, common for export, it’s 3 percent.

“Every field didn’t have damage, but I’ve seen levels of 30 to 40 percent, Hurburgh said. “The market is going to have to spread out some of the problems more than normal.

“Things could get a little dicey if farmers hold damaged soybeans into the summer,” he added. “They probably want them gone by then. Otherwise, good quality soybeans can be stored a year or more.”

To maximize soybean shelf life to take advantage of possibly better prices in the future, Hurburgh offered the following tips for the crop already in the bin or in the field:

  • Don’t allow high-moisture soybeans to sit in wagons, trucks or bins without aeration for a long period. Quickly cool and remove excess moisture using fans.
  • Keep soybeans cold, about 30 degrees.
  • Maintain moisture at 13 percent or less.
  • Take the center core out of bins to remove foreign material.
  • Check bins more frequently.
  • Avoid storing in bins/structures without aeration. If needed, install a screw-in aerator.

“The worst time to market damaged soybeans is right out of the field,” Hurburgh said. “The system has as much damage as it can tolerate with export specs for No. 2 beans at 3 percent.

“We were real lucky that daytime temperatures hit 50 to 60 degrees for a while and dew points were in the 20s,” he continued. “After two to three weeks of aeration, it made things a lot better.”

Tom Adam of Harper finished soybean harvest three weeks ago. The Iowa Soybean Association District 9 director and Communications Squad member heeded Hurburgh’s storage advice.

He aerated soybeans since moisture exceeded 15 percent at the start of harvest and removed bin cores.

“I feel pretty confident my soybeans will store well, but I will monitor bins closely,” Adam said. “We had several good drying days with the fans running, so I think I got them dried down to 13 percent.”

Adam forward contracted some soybeans for November and January delivery. For un-marketed bushels, he plans to store them with hopes of better prices ahead.

“I’m sure a lot of people are storing more soybeans,” Adam said “I’m not holding out for $10 beans, though. It will be a tight year I think.”

Some farmers use automated grain management systems. IntelliFarm’s BinManager is designed to take the worry out of long-term storage.

The system monitors moisture content and temperature of grain using cable sensors. It uses this information and the outside air to determine when to run fans to prevent spoilage, shrink and over-drying. The system also alerts the farmer via text message or email if there’s a problem.

“We test each variety differently for calibration as well as what air is best to run for drying and hydrating,” said Dave Ahearn, IntelliFarms vice president.

Even though some soybeans will test dry, Ahern said other beans and pods in a bin may be wet. Air flow is needed to equalize moistures and temperatures.

Ahern also recommends farmers avoid blending highly-damage soybeans with good ones.

“This just makes for problems further down the line and drives down the market for everyone,” he said.


Contact Matthew Wilde at

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