This year's late, wet harvest left farmers in a wide swath of the nation dealing with unusually high-moisture soybeans and lots of questions about how to handle them.
"I've seen soybeans with up to 24% moisture this year. Few farmers have much experience drying soybeans, and few elevators are set up to handle them. Most of the drying equipment is pointed at corn,” says Charles Hurburgh, Iowa State University ag engineer.
"Overnight storage of wet soybeans in a wagon or truck can have a marked effect on future storability. Always get wet grain into an aerated storage immediately,” Hurburgh says.
Moisture content of soybeans should ideally be around 13% when sold, says Bill Wilcke, University of Minnesota ag engineer. Most soybean processors can remove only about 2% of moisture, Hurburgh says.
"Above 15%, the soybean ends up as paste in the baking process. If it goes to a pasty slab, there's your problem,” Hurburgh says.
The best way for farmers to dry soybeans is by blowing natural air through them or using very low heat.
"If you dry them quickly, you tend to overdry them,” Hurburgh says. "Natural air in November in Iowa will normally take soybeans down to 13½%.”
Even when using natural air, pay close attention to what's going on in the bin. "For successful natural air drying in Iowa, plan for at least 1.25 cu. ft. per minute of airflow through grain. For grain up to 15' deep, 1 hp of fan per 1,000 bu. of grain will usually meet that goal,” says Joel DeJong, Extension agronomist in Le Mars, Iowa.
Go easy when using heat to dry soybeans. "Heat no more than 120°F will be adequate. High heat cracks the beans. You also raise the likelihood of having a spectacular dryer fire. The object is basically to warm them up, then cool them right down again so you don't overdry them,” Hurburgh says.
Bin selection. To hold soybeans through winter, be selective about which bins are used.
"Decide which bins are going to be kept into summer. Remove the center core and use a grain distributor if possible. Check grain every two weeks, with some way to take grain temperatures. If a slow rise is noted, aerate. If a hot spot starts, move the grain out. It is very difficult to control soybean spoilage once it has started. Oil rancidity becomes a major problem,” Hurburgh says.
- December 2009