How could a changing climate impact weed control? Will some weeds prosper? Will the herbicides farmers have in their management toolbox be more or less effective as conditions change?
Cornell Cooperative Extension agriculture educator Sharon Bachman tackled these and other questions when she spoke to CCAs attending the Ontario Certified Crop Advisors meeting in London, Ontario. She shared findings from Cornell University’s Weeds and Climate Change Project on how weather events, including wetter springs and warmer summers, could impact the efficacy of herbicides farmers currently use to control weeds in their crops.
In this interview with RealAgriculture’s Bernard Tobin, Bachman notes that Cornell research indicates that perennial weeds will be harder to control because changing weather tends to favour increased root biomass over shoot biomass, making mechanical control methods, including tillage, less effective. Physiological changes in weeds species, including absorption, uptake and translocation, will also impact herbicide options. Bachman adds that how weeds compete with crops will also depend on whether they are C3 or C4 plants and their photosynthesis efficiency.
Cornell also looks at the efficacy of current herbicides and how active ingredients would perform in changing climate conditions. The research indicates that efficacy would be impacted by higher temperatures, increased CO2, drought, waterlogging and combinations of these conditions.
When it comes to specific herbicides, Cornell data shows that glyphosate’s efficacy varies with CO2 levels, temperature, and drought, with mixed results across different plant species. Bachman notes herbicides react differently to specific conditions. For example, under higher humidity, glufosinate becomes more effective. Watch the video below.
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