Harvesting Grain Soybean Crops for Forage Production
We are experiencing severe late-season drought across Pennsylvania and beyond. Drought-stressed grain soybean crops might have limited pod formation and filling, resulting in a lower grain yield. Forage production and inventory can also be low due to the late-season drought. Therefore, harvesting drought-stressed grain soybean crops for forage production becomes a practical interest. Grain soybean crops are high in crude protein (18-20%), low in fiber (35-45%), and high-yielding (2-4 tons dry matter per acre). The palatability of soybean forage is lower than that of other popular forages, but it can be mitigated by mixing with other forages. Due to all the above-mentioned reasons, drought-stressed grain soybean crops can be harvested as forage. However, several factors have to be checked before chopping soybean crops for forage production.
Pesticide application restrictions
One of the main limiting factors to chopping soybeans as a forage will be pesticide applications, primarily herbicides. Many commonly used products such as Liberty, Enlist One, Reflex/Flexstar, Dual, Canopy, Pursuit, Sonic, Select, Warrant and numerous others do not allow the soybeans to be cut as a forage. Others such as Roundup PowerMax3, FirstRate, metribuzin, and a few others do allow cutting for forage but only after a certain PHI (pre harvest interval) of 14-65 days or more depending on the product. Refer to Table 2.4-16 in the 2025 Penn State Agronomy Guide for an overview of herbicide product restrictions. Also fungicides and insecticides can also have certain limitations. So it is always best to check current product labels to be sure harvesting as a forage is allowed and if there is a wait period.
Crop insurance
If you use crop insurance for your soybeans, be sure to talk to your crop insurance agent before starting to cut the soybeans to find out how it will affect your crop insurance.
USDA programs
Be sure to communicate with your USDA Farm Service Agency office to see if harvesting the grain soybean field for forage will affect your USDA program eligibility.
After all the cautious checks, you decide to harvest your grain soybean crops for forage production, several management practices can be considered.
Harvesting time
The optimum harvesting time is right before the soybean maturity stage of R7, i.e., at least one pod on the main stem reaching its mature tan or brown color. At this stage, the plant stops significant seed development, dry matter accumulation peaks, seeds have about 60% moisture, and the leaves will be yellowing. Under drought-stressed conditions, harvesting soybeans before leaf drop will be better to reserve the forage quality.
Harvesting modality
Harvesting soybean crops as silage or baleage is preferred over dry hay. Dry soybean hay is often dusty with brittle stems and wet beans containing too much moisture, and may mold. Field wilting is needed before ensiling. The moisture levels for silage are about 65-70% and for baleage are about 40-60%. Appropriate conditioning set up in the harvesting mower will be the key to accomplishing the field wilting without losing significant soybean leaves when chopping or baling.
Feeding
Mixed with other grass forages will be preferred for two reasons: first, to lower the average oil content that can cause digestive issues; second, to improve palatability and decrease animal refusal.
For detailed information, please visit Using drought-stressed soybeans for hay or silage.
