Late-planted soybeans that don't mature before the fall frost can be salvaged as hay or silage, according Bruce Anderson, University of Nebraska Extension forage specialist.
Soybean hay and silage can have feeding values similar to alfalfa, at least when they're made right.
"Start by harvesting soybean forage no later than when leaves start to turn yellow, before they drop off," Anderson says. "It's especially important to harvest before a freeze to prevent rapid leaf loss."
But he cautions that soybean hay is challenging to make, as leaves dry quickly and then become crumbly if raked, while the stems are quite woody and dry slowly.
Be sure to condition or crimp the hay to hasten stem drydown, and avoid raking if at all possible, Anderson recommends.
"Soybean leaves crumble easy when dry, which will cause some yield loss and much lower feed value, he says. "If you must rake, such as putting several windrows together for baling, do it within one day of cutting."
Making good soy silage is less risky if you have silage equipment and do it right, according to Anderson.
"I prefer mixing chopped soybeans with corn or sorghum since they're being ensiled, but that's not always possible," he says. "For straight soy silage, first get a good, clean chop. Uniformly add a silage inoculant designed for legumes such as alfalfa. In addition, add about 1 bushel of rolled corn or 50 pounds of molasses to each ton of wet silage to aid fermentation. And pack soy silage especially well."
Silage of any type should be covered with black plastic immediately after you finish filling the trench, bunker or pile, Anderson says. Then cover the plastic with something to hold it down.