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  • Cornell Cooperative Extension
Impact: Agricultural Systems

Weed pressure remains one of the most persistent and costly challenges facing both organic and conventional farmers. Weeds compete directly with crops for water, nutrients and light, leading to reduced yields and profitability when not effectively managed. Traditional weed control practices, including intensive tillage, frequent cultivation and repeated herbicide use, can contribute to soil degradation, increased erosion, reduced water quality and higher greenhouse gas emissions. As farmers face rising input costs and increasing pressures from extreme weather, there is a growing need for weed management strategies that protect soil health, reduce reliance on chemical inputs and support long-term farm sustainability. Developing effective ecological weed management approaches is essential to maintaining productive agricultural systems while meeting environmental and climate goals. 

Cornell University researchers partnered with an advisory group of farmers to evaluate ecological weed management strategies that reduce dependence on herbicides and intensive tillage. Research activities included testing cover crop systems, strategic inter-row mowing, and emerging mechanical and robotic weed control technologies. The long-term Organic Cropping Systems (OCS) trial compared four organic management treatments differing in fertility levels, amounts of tillage, and weed management practices to assess agronomic, environmental, and economic trade-offs. In addition, researchers parameterized the Farm Energy Analysis Tool (FEAT) with values from the OCS to better evaluate system-level impacts related to soil health, labor requirements, profitability, energy use, and greenhouse gas emissions. Farmer input helped guide research priorities and ensure relevance to on-farm decision-making. 

Results

Field research demonstrated that inter-row mowing and other mechanical weed control tools improved weed suppression in organic no-till soybean systems. Cover crop-based rotations and reduced tillage practices can support soil health and reduce erosion and reliance on herbicides. Farmers increased their knowledge of alternative weed management tools and strategies through participation in on-farm research and outreach activities. Advisory board involvement helped align research outcomes with farmer needs, while students and technicians gained hands-on experience with sustainable weed management practices. Refinements to modeling tools provided new insights into energy use and greenhouse gas emissions across different cropping systems, supporting more informed evaluation of ecological trade-offs. 

Public Value Statement

By advancing ecological weed management strategies, Cornell University supports farming systems that reduce dependence on herbicides and fossil fuels while protecting soil and water resources. These approaches promote resilient agricultural systems, contribute to climate mitigation goals, and expand viable weed management options for organic and transitioning farmers, benefiting both agricultural producers and the broader public. 

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