Dairy producers are increasingly exploring the potential of harvesting soybeans for silage, a high-protein forage alternative, particularly in regions where traditional forages like alfalfa struggle to thrive. Historically, soybeans were used as a forage crop in the United States, and over two decades ago, University of Wisconsin Forage Professor Emeritus Dan Undersander provided guidance on utilizing soybeans for hay or silage, primarily as a rescue crop or on prevented planting acres. Today, more producers are intentionally growing soybeans with forage production in mind.
Experts recommend approaching soybean silage production with a forage mindset rather than a grain mindset. Jim MacEwen of MacEwen Agricentre, Inc., notes that planting techniques resemble those of alfalfa more than conventional soybeans, with seeding rates of 190,000–205,000 seeds per acre and row spacing of around 15 inches to balance plant density with field access for fungicide and weed control. Fungicide is particularly crucial to prevent white mold, which can reduce forage quality and palatability.
Harvesting soybean silage involves cutting wet plants, allowing a few days of drying, then chopping and storing in a bag or bunker. Michigan State University advisors recommend a 3/8-inch cut on the chopper and a whole-plant moisture level near 65% for optimal ensiling. Yields of 4–5 tons per acre are typical. Producers must also consider the crop’s high oil content, which can interfere with fermentation if too mature, and carefully manage crop protection products to ensure they are safe for forage feeding.
