Detection and Dissipation of Isoxaben and Trifluralin in Containerized Plant Nursery Runoff Water

• Published in: Weed science 1996-09, Vol.44 (3), p.683-688
• Main Authors: Wilson, C., Whitwell, T., Riley, M. B.
• Format: Article
• Language: English
• Subjects: chemical composition; dark; degradation; duration; Groundwater; herbicide residues; Herbicides; irrigation; Irrigation water; isoxaben; light; plant nurseries; Ponds; runoff; Runoff irrigation; Sediments; Soil, Air and Water; Stormwater; Surface runoff; Surface water; trifluralin; Water samples
• ISSN: 0043-1745; 1550-2759
• DOI: 10.1017/S0043174500094534

Herbicides used in containerized plant production have a potential to move off-site in irrigation runoff water. A granular formulation of isoxaben plus trifluralin was applied to a commercial container plant nursery bed. Herbicides were monitored in irrigation runoff and collection pond water over a period of 60 d. Greatest quantities of both herbicides were lost during the first runoff event following application. Approximately 9.2 and 0.7% of the applied isoxaben and trifluralin, respectively, moved from the application site in runoff water within 5 d after treatment. Herbicide concentrations in runoff water were highest (0.75 μg ml−1 isoxaben and 0.08 (μg ml−1 trifluralin in 1992) during the first 0.25 h following herbicide application. Concentrations in the runoff collection pond climaxed following the first runoff event and decreased to less than 1 ng ml−1 within 60 d after treatment. Photodegradation of isoxaben within the surface 2.5 cm of pond water was greater in light as compared to dark. These studies indicate that isoxaben and trifluralin move from the site of application, but that neither accumulate in the runoff water collection ponds.