Waterhemp is currently the most troublesome weed in soybean production across wisconsin and much of the midwest

The University of Wisconsin–Madison received a $200,000 project grant awarded September 1, 2025, through the Crop Protection and Pest Management Competitive Grants Program (USDA NIFA, CFDA 10.329) to develop integrated weed management strategies for waterhemp control in soybean production. The research project, which extends through August 31, 2027, will deliver field studies and controlled-environment experiments evaluating cereal rye cover crop management practices and preemergence herbicide applications to suppress waterhemp populations and reduce soybean yield losses. Key deliverables include data on weed density, growth patterns, seed germination responses, herbicide soil persistence, and soybean yield outcomes. The research aims to identify practical, sustainable management strategies that reduce dependence on postemergence herbicides while maintaining herbicide efficacy and soybean productivity across the Midwest.

Additionally, the project will serve as a training platform for students and early-career professionals in agronomy and weed science, providing hands-on experience in research design, field management, and data analysis. By addressing herbicide-resistant waterhemp populations through mechanistic understanding of cover crop and preemergence herbicide interactions with weed biology, this grant directly supports the CPPM program's objectives to provide integrated, multifunctional agricultural research addressing high-priority pest management challenges while promoting sustainable agricultural production and environmental stewardship.

Populations of waterhemp resistant to commonly used postemergence herbicides have become widespread, making this weed increasingly difficult and costly to manage. Uncontrolled waterhemp reduces soybean yield, increases production costs, and can negatively impact farm profitability. Beyond the farm, excessive herbicide use to combat resistant weeds can affect local ecosystems, contaminate water sources, and contribute to broader environmental concerns. Developing integrated weed management (IWM) strategies that combine multiple approaches is essential for sustainable soybean production, economic stability for farmers, and environmental stewardship. This project will evaluate how the management of cereal RYE cover crops and the use of preemergence herbicides influence waterhemp control and soybean production. Field studies will be conducted to test different planting and termination practices for cereal RYE and how these interact with commonly used preemergence herbicides to affect waterhemp density, growth, and seed germination. Controlled-environment studies will complement field experiments by examining how waterhemp seeds respond to light and temperature conditions under cover crop residue. Data will be collected on weed growth, seed germination, herbicide persistence in the soil, and soybean yield. Researchers will also use these studies as training opportunities for students and early-career professionals in agronomy and weed science, providing hands-on experience in research, field management, and data analysis. The ultimate goal of this research is to identify and optimize practical, sustainable strategies for waterhemp management that reduce reliance on postemergence herbicides, preserve herbicide efficacy, and maintain high soybean yields. By understanding how cereal RYE cover crops and preemergence herbicides interact with waterhemp biology, the project will provide science-based recommendations that farmers can implement directly in their fields. The anticipated societal benefits include improved economic outcomes for soybean producers, reduced environmental risks from herbicide overuse, and the advancement of sustainable agricultural practices that support long-term crop productivity. Additionally, this research will inform outreach programs and extension resources, helping farmers and agricultural professionals adopt integrated weed management practices effectively.