INTEGRATING CHAFF LINING AS AN ECOLOGICAL TACTIC TO MANAGE HERBICIDE-RESISTANT PIGWEEDS IN U.S. SOYBEAN PRODUCTION

The main goal of this applied research (ARDP, single function) is to integrate two innovative IWM tactics, namely, cover crop and HWSC (chaff lining), within an integrated weed management (IWM) framework, for managing pigweed (Palmer amaranth and waterhemp) seedbanks in soybean-based cropping systems of the Midwest, South, and Central Great Plains, with a long-term aim of developing resilient weed management systems with reduced economic and environmental risks from HR pigweeds. In order to accomplish our long-term goals, we propose the following Specific Objectives (SO) for this applied research project:Integrate ecologically-based IWM strategies, namely, cover crop and chaff lining (HWSC), for managing pigweed seed banks in soybeanField and laboratory studies to determine the impact of cereal rye cover crop, chaff lining (HWSC) on Palmer amaranth and waterhemp seed bank dynamics (germination/emergence pattern/periodicity, density, seed viability, seed predation), crop-weed competition (growth, biomass), control, and end-season seedbank inputs.Evaluate the efficacy of chaff lining (HWSC) as a novel, cost-effective IWM tactic in reducing HR pigweed seed banks, with emphasis on:Percent seed retention at soybean harvestHeader loss of pigweed seeds at soybean harvestEfficacy of chaff lining to concentrate pigweed seeds in narrow bands and prevent spread of HR weed seedsOn-field assessments of how regional weather variables across four major U.S. soybean production states (Iowa, Illinois, Kansas, and Arkansas) interact with IWM practices (cereal rye cover crop by herbicide by chaff lining) at a system level to mitigate risk of weed resistance evolution.2. Quantify the economic benefits and risks of adopting a diversified IWM program to mitigate herbicide resistance for development of decision support tools (DSTs) for producers and other stakeholders.