Recent research shows promise for controlling herbicide-resistant weeds, such as waterhemp, in soybean fields by using a seed impact mill at harvest.
Gilbert, IA (January 16, 2025) - Recently published research in the journal Weed Science shows promise for controlling herbicide-resistant weeds in soybean fields by using a seed impact mill at harvest. When installed on a combine, this harvest weed-seed control system (HWSC) mechanically damages weed seeds as they move through the mill to render them non-viable.
Iowa State University Researchers Alexis Meadows and Ram (Ramawatar) Yadav conducted seed impact mill field experiments during 2021 and 2022 on a commercial farm near Gilbert, Iowa. “Altogether, impact mill treatment reduced the number of germinable seeds by 87% compared with the no–impact mill treatment,” says Yadav, a Ph.D. Weed Science Society of America (WSSA) member scientist and now a specialty crop weed science assistant professor at The Ohio State University. “These results indicate that seed impact mills can be a useful tool in soybean production to help manage multiple herbicide–resistant waterhemp populations.”
The HWSC technology used for the study was a Redekop™ Seed Control Unit, mounted on the rear of the combine. “Although the impact mill did not severely damage all of the waterhemp seeds, moderate damage to seeds was effective in reducing seed germination and viability in controlled conditions,” notes Yadav. “Furthermore, seeds with moderate damage are less likely to persist in the soil seedbank due to increased seed mortality.”
By adding seed impact mill technology to current weed-control practices, researchers estimate future herbicide-resistant populations could be delayed by five to eight years. However, Yadav cautions that this technology is not the sole answer to herbicide-resistant waterhemp management. “Implementation of HWSC methods in Iowa cropping systems is not a replacement of existing weed control tactics but rather an expansion of the weed management toolbox,” he says.
The good news is that other non-chemical weed control tactics can also work in tandem with herbicide treatments, in addition to seed impact mills, to effectively manage herbicide-resistant waterhemp, says Yadav. Other effective non-chemical weed control tactics include implementing a cereal rye cover crop and narrow-row soybean production systems, he adds.
This project was led by Alexis Meadows, a former M.S. student in the Department of Agronomy at Iowa State University. To learn more, contact Yadav at yadav.206@osu.edu, 330-263-8063.
More information is available in the article, “Using a seed impact mill to limit waterhemp (Amaranthus tuberculatus) seed inputs in Iowa soybean.” The research is featured in Volume 72, Issue 6 of Weed Science, a Weed Science Society of America journal, published online by Cambridge University Press.
