Monitoring herbicide leaching in sustainable vegetable culture using tension lysimeters

Abstract

In Kentucky, "Best Management Practices" (BMP) are recommended for use in sustainable agricultural systems to retard soil, water, and pesticide loss, and therefore preclude non-point source pollution of surface water systems (Anonymous 1989). These practices may include landscape feature alterations which are designed to prevent surface water pollution, but may increase infiltration. If herbicides are used in these production systems, their movement in surface water may be prevented, but their potential to leach may increase. Herbicides used in conventional agriculture may move from the site of application to ground water (Leonard and Knisel 1988, Helling 1986). At least 17 pesticides have been detected in groundwater samples collected from a total of 23 states and about half of these chemicals were herbicides (Cohen et al. 1986). To determine leaching potential, herbicides can be monitored using tension lysimeters. Lysimeters have been used to collect soil percolate since the early 1960's due to their ability to render adequate volumes of water, low failure rate, and minimal alteration of the soil environment (Angle et al. 1991).