Evaluating the efficiency of glufosinate and clethodim in varying water qualities in combination with water conditioners in canola
Term: 1 year ending Feb 2025
Status: Completed
Researcher(s): Koralie Mack, WARC
SaskCanola Investment: $11,000
Total Project Cost: $11,000
Funding Partners: N/A
Grower Benefits
This study examines the interactions between the full and half rates of both glufosinate and clethodim in a tank mix with and without a water conditioner across varying water qualities.
A high-yielding glufosinate- tolerant canola variety was seeded in the seed row alongside wheat in the mid-row bands seeded as weeds. Herbicide efficacy was evaluated through phytotoxicity ratings, weed counts, yield, and grain quality analysis. Visual assessments of the treatment solutions after mixing revealed significant differences in the opacity of the solutions. All treatments experienced a pH drop, with a more pronounced decrease with the addition of a water conditioner. Phytotoxicity ratings at 7, 14, and 21 days after application (DAA) showed that all treatments exceeded acceptable weed control levels by the first assessment. Early on, the lowest efficacy was identified in treatments with hard water and no water conditioners or soft water with no water conditioner and low herbicide rates. By 21 DAA, all treatments had achieved 98% weed control. Overall, full herbicide rates enhanced weed control at 7 (p=0.022) and 14 (p=0.029) DAA, while water conditioner addition also significantly enhanced control (p=0.019; p=0.025). However, the actual phytotoxicity variance between herbicide rates and water conditioner was extremely low. No statistical yield trends were detected, but an interaction between herbicide rate and water conditioner influenced seed oil content, higher herbicide rates with a water conditioner significantly increased the seed oil content (p=0.032), while half rates reduced it. Overall, the results suggest that adhering to the recommended rates of glufosinate, clethodim, and a water conditioner improves the consistency of weed control and suppression. While water quality did not have a significant impact on herbicide efficacy in this study, it did influence the pH and clarity of the treatment solutions. This highlights the importance of understanding water quality, as it can affect the application and effectiveness of herbicides and other products in different environmental conditions.