Metolachlor and simazine in surface runoff water from a simulated container plant nursery

Field trials were conducted to evaluate the influence of three application methods and two types of ground cover on the transport of metolachlor and simazine from container-grown junipers. Application methods used were broadcast spray, broadcast granules, and individual container applications. Woven ground cloth and woven ground cloth plus gravel were used as ground covers. The site received daily irrigation, and surface runoff was sampled and analyzed 0, 1, 2, 4, 8, 16, 32, and 56 d after herbicide application. Application method had the greatest effect on herbicide concentrations in runoff. Herbicide application to individual containers resulted in lower simazine and metolachlor concentrations in runoff. Herbicide concentrations took longer to drop below detection levels in surface runoff from broadcast applications.