INTEGRATING HIGH-RESIDUE COVER CROP AND RESIDUAL HERBICIDE TACTICS TO IMPROVE HERBICIDE-RESISTANCE MANAGEMENT IN MID-ATLANTIC FIELD CROPS.

The evolution and spread of glyphosate and multiple herbicide-resistant weeds has led to significant increases in herbicide use and farm-level weed control costs within no-till field crop productions systems across U.S. regions.Development and communication of proactive, integrated weed management (IWM) strategies that employ non-chemical tactics to reduce the likelihood of herbicide resistance evolution is urgently needed. Cover cropping is unique among potential IWM tactics in that current interest and adoption is primarily driven by long-term sustainable agroecosystem management goals. Understanding of interactions between high-residue cover crops and use of soil-applied residual herbicides is a significant knowledge gap that prevents improved efficacy of integrated tactics. Our goal is to improve understanding of how high-residue cover crop management tactics (termination timing, species selection, residue management) influence the fate and efficacy of soil-applied residual herbicides. Field experiments will be conducted to (1) quantify the interactive effects of cover crop residue and residual herbicide properties on herbicide fate processes, including interception, retention, and soil bioavailability, and (2) evaluate interactions between high-residue cover crop and residual herbicide management tactics on population dynamics of multiple herbicide resistant weeds. Anticipated impacts of our integrated research and extension project include improved producer knowledge of best management practices (BMPs), conceptual approaches, and long-term management goals for employing proactive IWM to manage and prevent herbicide resistance.