Field trials were conducted at the Saskatchewan Irrigation Diversification Centre (SIDC), Outlook, Sask.; Saskatchewan Wheat Pool (SWP) Research and Development Farm, Watrous, Sask.; AgrEvo Canada Inc. research facility, Indian Head, Sask.; Agriculture and Agri-Food Canada Research Farm, Scott, Sask.; and Kernen Crop Research Farm, University of Saskatchewan, Saskatoon, Sask. to investigate the effect of water quality of selected herbicide efficacy. Two water quality/herbicide screening trials were established to determine the effect of raw and treated (coagulated with aluminum sulfate) surface dugout water on the efficacy of grassy (Horizon, Puma Super, Poast Ultra, Liberty and Avenge 200C) and broadleaf (Refine Extra, Odyssey, 2,4-D Ester, 2,4-D Amine and Pardner) herbicides. Two additional trials were established to determine the effect of four sources of differing quality water (Raw Dugout, Treated Dugout, Hard and Local) and spray volume on the efficacy of Roundup Transorb and Reglone Pro. All treatments were applied below the recommended rate to exaggerate potential differences. Visual assessments were taken 14 and 21 days after application; above ground biomass was harvested 21 days after application.
Water treatment did not affect the efficacy of broadleaf products at SIDC, Scott, and U of S; only visual differences were observed at the AgrEvo site. At the SWP site, treated water increased visual control with Refine Extra, 2,4-D Ester and 2,4-D Amine but, only Refine Extra using treated water, significantly lowered the biomass. Results were varied for the grassy weed herbicides with water treatment having no effect at SIDC and no significant differences at the U of S and Scott sites. Treated water provided improved visual efficacy of Horizon at the SWP site and Poast Ultra at both SWP and AgrEvo sites. However, treated water reduced the efficacy of Avenge at the AgrEvo site. The results of water treatment and water volume for Roundup and Reglone were extremely variable among the five sites.