High carbon dioxide concentration and elevated temperature impact the growth of weeds but do not change the efficacy of glyphosate.

Abstract

Global climate changes may impact the growth and management of weed species. The aim of this work was to evaluate the impact of recent climate changes on the growth of weeds and herbicide efficacy. The effects of temperature, carbon dioxide (CO2 ), and herbicide on growth and control of Bromus tectorum L., Hordeum murinum L., and Lactuca serriola L. were studied. Treatments included: control or ambient environment (CO2 concentration 400-450 ppm; temperature 20/10 °C day/night); elevated temperature (CO2 concentration 400-450 ppm; temperature 25/15 °C day/night); high CO2 and elevated temperature (CO2 concentration 800-900 ppm; temperature 25/15 °C day/night); high CO2 (CO2 concentration 800-900 ppm; temperature 20/10 °C day/night). Glyphosate rates (active ingredient) used in the experiment were: 0 g ha-1 (untreated control); 360 g ha-1 ; 720 g ha-1 ; 1080 g ha-1 ; 1440 g ha-1 (recommended rate), and 2880 g ha-1 . High CO2 concentration and high CO2 concentration plus high temperature improved the biomass and growth parameters of weeds in the studies. In general, high temperature had a neutral, negative or slightly positive effect on the growth of weed species. Climatic conditions did not affect the activity of glyphosate; its application provided equal and effective weed control under both CO2 and temperature levels and their combinations. The positive effect of high CO2 concentration on the growth of weeds does not impact the activity of glyphosate. © 2017 Society of Chemical Industry.