Research Highlights

Aligning Soybean Seed Treatments with Management Practices for Optimum Performance

Highlights:

• North Dakota State University researchers are conducting trials of various seed treatments for best soybean stands, reduced disease severity, and yield.
• Seed treatment performance under different seeding rates and planting dates are also being studied across the state.
• Results can help farmers make decisions on which sites of action to select under their production systems for the best return on investment.

By Carol Brown

To many farmers, soybean seed treatments are essential, and knowing which treatments to include in an operation is where the decisions are crucial. In North Dakota, where soybean production is relatively new compared to the rest of the country, not all farmers view seed treatments as a necessity. A research team is looking at how soybeans are growing with and without these protective coatings under several variables.

Led by Richard (Wade) Webster, a soybean pathology specialist at North Dakota State University, the team is conducting trials at three locations across the state to explore a variety of soybean seed treatments with different seeding rates and planting dates as well as with cover crops.

The project is in its second year and supported with Soy Checkoff funding from the North Dakota Soybean Council. Results will help farmers make decisions when choosing appropriate seed treatments for seedling disease control.

Webster was surprised to find that nearly half of the farmers in central and western North Dakota were not using seed treatments, based on an unofficial survey he conducted a few years ago. This led to further exploration as to seed treatment effectiveness in these areas.

“In North Dakota, margins are tight especially on the western side of the state, which has less productive ground and a shorter growing season,” Webster comments. “Seed treatments are an additional expense in which some farmers here don’t see an immediate return on that investment.”

Numerous Test Combinations 

Webster and his team began conducting trials in 2024, consisting of soybeans with nine different seed treatment programs. Some of these seed treatments were then combined with two seeding rates and two planting dates, making for a complicated tapestry of research acres.

One of the trials compared seed treatments ranging from a single product to a combination of three products and multiple sites of action for a total of nine comparisons, plus a non-treated check plot. This trial is conducted at Fargo, the Oakes Irrigation Research site and the Williston Research Extension Center. At the Fargo and Oakes sites, the trial results were as Webster expected with the non-treated soybeans having the lowest stand and yield. The single mode of action seed treatments, Allegiance and Relenya, performed similarly to the non-treated soybeans (Figure 1). 

But the western trial results were quite different and surprising to the researchers. The Williston site — located in northwest North Dakota, close to the Montana and Canada borders — had a fairly wet spring, which means the seed treatment chemicals could be degraded due to the wet soils. Webster expected to see higher levels of seedling diseases, but that was not the case (Figure 2).

“I was not expecting to see that certain products performed worse than the non-treated seeds,” Webster comments. “It was the opposite of my original hypothesis going into the trial. But the results were from only one season, so we are conducting these tests again this season.”

In addition to finding the best combination of good yields with reduced disease severity, the team is also exploring seed treatment profitability. They conducted a partial profit analysis for the treatments using costs estimated from ag retailers across the state and a soybean sale price of $10 per bushel. At the eastern sites, most of the seed treatments and combinations improved profitability compared to the non-treated soybeans. Again, the Williston site had different results with the non-treated soybeans in the higher profitability range. 

Seeding Rates, Planting Dates in the Mix

When seed treatments are combined with seeding rates and planting dates, Webster and his team wanted to know if an earlier planting date was an asset or hinderance for germination and ultimately yield.

“Earlier planting allows for greater photosynthetic activity for the plant, but it also can have added stress as the seeds are in the ground longer,” Webster says. “If planted later, maybe we wouldn’t see as much of a stand loss and maybe the lower seeding rates would be able to maintain yield.”

The trials were conducted at Fargo and Carrington, with rates at 130,000 and 170,000 seeds per acre along with June 14 and June 28 planting dates. The second planting date is much later than a farmer would typically plant, Webster says, but the delay was due to wet field conditions.

“Although it is early to draw any broad conclusions yet, we saw certain products performed better at higher seeding rates with both planting dates,” he says. “This trial had a range of one to four sites of action in the seed treatments. When more chemicals were added, the yields also increased.”

Cover Crops Added in Year 2

The team seeded a winter rye cover crop last fall at three locations: Gardner, Dickinson and Minot, to help understand the cover crop and seed treatment relationship. After this fall’s harvest, the team will analyze soybean yields across the different seed treatments, as well as with cover crop and no cover crops, to learn the effectiveness of seed treatments in a cover cropping system.

“Farmers in western North Dakota are interested in cover crops because of their erosion and water retention benefits, but the short soybean growing season and lack of rainfall can be limitations,” comments Webster. “We want to learn of these relationships so we can make the best recommendations to farmers when they are ready to commit to a cover crop system.”

Seed treatment products in the trials, singularly or in combination, include:

• Allegiance
• Relenya
• Vibrance Trio
• CruiserMaxx APX
• Cruiser 5FS
• Lumiderm
• Acceleron D281

Additional Resources

Biological Seed Treatments: The Big Picture – SRIN article

Seed Treatments: Questions that Emerge When Plants Don’t – Crop Protection Network article

Meet the researcher: Richard (Wade) Webster  SRIN profile | University profile

Published: Nov 3, 2025

The materials on SRIN were funded with checkoff dollars from United Soybean Board and the North Central Soybean Research Program. To find checkoff funded research related to this research highlight or to see other checkoff research projects, please visit the National Soybean Checkoff Research Database.