By Scout Nelson
Biostimulant seed treatments continue to gain attention in soybean production. These products promise stronger early growth, better stress control, and higher yields. A new nationwide research study from the University of Minnesota tested whether these claims work under real farming conditions.
The study included trials from 103 locations across 22 states. Researchers used a farmer focused research method that followed how seed treatments are applied in real fields. The results appeared in the scientific journal Field Crops Research in December 2025.
The goal of the study was to find out if biostimulant seed treatments can increase soybean yields in different environments. As one of the study authors explains, “We were really looking for which products worked in the most locations—and then trying to identify characteristics of environments products worked in—so that we could channel the use towards areas that would have a greater potential response or a better ROI.”
The research team selected products that are commonly used by growers. Each state tests eight to ten commercial products. All seeds received a base of fungicide and insecticide treatment, with biostimulants added on top. Seed was stored in cold conditions, treated just before planting, and placed in high quality production fields.
“We did our absolute best to get the best possible outcome from these products.”
Even with careful handling and ideal placement, the results are clear. Across all 103 locations, no biostimulant product showed a consistent yield increase. As one researcher states, “The biggest surprise of anything is that nothing worked anywhere.”
Only traditional inoculants showed limited positive results at a few locations. This aligns with long known agronomy practices rather than new product claims.
The study showed that seed applied biostimulants face many challenges. Living organisms must survive storage, coating, and soil competition. Field conditions also vary widely, making reliable results hard to achieve.
“There’s a million ways where these things can go wrong, and everything has to go right for them to work.”
The findings suggest these products should not be viewed as yield insurance. Small local testing is encouraged before large scale use. Proven practices like proper variety of choice, planting time, fertility, drainage, and pest control remain the most reliable ways to protect soybean yields.
Photo Credit: gettyimages-zoran-zeremski
Categories: Minnesota, Crops, Soybeans, Education