Sulfur for Stronger Soybeans: Field Trials Highlight Yield Gains from Ammonium Sulfate

Across North America, soybean growers are looking for ways to push yields higher and improve crop health. Many are turning to a familiar fertilizer with fresh potential: ammonium sulfate (AMS). Recent field trials supported by AdvanSix's Supplement Your Soybean program continue to show that the addition of sulfur can make a big difference.

More Nodes, More Beans

During a recent visit to Ontario, Canada, AdvanSix's Regional Sales Managers David White, Manufacturing Manager Casey Inzania and Senior Agronomist Mercedes Gearhart met with Sylvite Agri Services crop consultant Emily Cook and local grower Edward Campbell, who have been testing AMS on soybean crops.

Campbell's field trials included fields with and without AMS, and the team noted that AMS-treated soybeans produced about one extra node per plant. "That matters," said Gearhart. "You need nodes to have pods, and pods to have beans. Even a small increase can add up to a real yield difference." The extra node count suggests higher pod potential, a result that the upcoming yield data is soon expected to confirm.

The Benefits

In many AdvanSix trials across Ontario and the U.S. Midwest, AMS-treated soybeans stand out visually: leaves are darker green, larger and remain green longer into maturity. Those traits point to stronger photosynthetic activity, an important contributor to yield.

"Typically, we'll see a five- to seven-bushel-per-acre improvement where AMS is applied," said White. "On sulfur-deficient soils, the difference can be even greater."

Another advantage appears early in the season. AMS-treated soybeans tend to grow a canopy faster, capturing sunlight more efficiently and shading out weeds. "A quicker canopy formation not only supports better photosynthesis, but also keeps fields cleaner," Gearhart explained. "That means less competition for water and nutrients, in addition to reduced herbicide use and costs."

Why Sulfur Matters Now

While growers once relied on atmospheric sulfur from industrial emissions that source has steadily declined over the past 20 years due largely to clean air regulations. "We used to get enough sulfur from acid rain," said Gearhart. "Now, with cleaner air, we need to replace what's missing and AMS is one of the most efficient ways to do that."

Interest in AMS use on soybeans has seen rapid expansion. Agris Co-operative Senior Agronomist Dale Cowan is leading 29 field trials involving 20 different farmers across Ontario this season. Combined with plots in Ohio, Michigan, Indiana, and Illinois, these studies are helping growers better understand how sulfur supports soybean performance in a range of conditions.

"It's exciting to see the momentum," said White. "Programs like Supplement Your Soybean are helping growers see firsthand how AMS fits into modern farming."

As growers across the region continue to harvest and compare results, one thing is becoming clear: ammonium sulfate can offer measurable advantages for soybean performance. Learn more about how AdvanSix's Supplement Your Soybean program helps North American farmers by visiting the program homepage.

Photos from being on-site at AdvanSix's Supplement Your Soybean program: