Frost-bitten Soybeans?

What to do with those green soybeans.

Published on: Oct 22, 2009
Last week, Jack Frost nailed many Mid-Atlantic fields of late-planted soybeans. We took a read of sound advice offered to frost-bitten producers in other states. Here's a quick summary of what we found.

Soybean seed that are still green when hammered by frost tend to stay green, even as they dry down. The problem is that the remaining chlorophyll causes oxidation of the oil, and greatly reduces shelf-life. That's why green beans are severely discounted or rejected by processors, mills and elevators.

Drying and marketing strategies to consider

A University of Minnesota study suggests that green soybeans that are dried in the field or in dryers don't appear to present any greater storage risk than yellow beans. Clean, yellow soybeans can be in aerated storage for up to six months if maintained at moisture contents of 13% or lower. But when beans are harvested with high foreign materials (weed seed and the like), it's advisable to reduce storage moistures to 11-12% moisture or lower to be safe.

Moisture readings will generally read low on immature (butter beans) soybeans fresh out of the field. But they should stabilize after a few hours of equilibration at room temperature in a closed container.

The worst plan is to harvest green or immature soybeans wet, then market them immediately at harvest. To reduce potential for discounts, it may be desirable to screen out small beans before binning or delivery.

Find a 'ruminating' market

Dried down enough to prevent green beans from turning rancid, they make an excellent feedstuff for beef and dairy rations. Crude protein content and fatty acids in raw immature beans may run slightly higher than in mature soybeans, according to data from South Dakota State University.

Because of the higher moisture and fatty acids, soybean silage is tougher to ferment properly. Because of it, dry matter content is best aimed for 35 to 40%, suggests Alvaro Garcia, Extension dairy specialist at SDSU.