Submitted to: Environmental Toxicology and Chemistry
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 11/30/2010
Publication Date: 4/1/2011
Citation: Moore, M.T., Denton, D.L., Cooper, C.M., Wrysinski, J., Miller, J.L., Werner, I., Horner, G., Crane, D., Holcomb, D.B., Huddleston, G.M. 2011. Use of vegetated agricultural drainage ditches to decrease pesticide transport from tomato and alfalfa fields in California, USA. Environmental Toxicology and Chemistry. 30(5):1044-1049. Interpretive Summary: Irrigation and storm water runoff from agricultural fields can contain pesticides, which can damage rivers, lakes and streams. Vegetated drainage ditches can decrease the amount of pesticides entering water bodies by filtering and retaining some of the pesticides between the agricultural field and the receiving water body. Ditches were able to decrease the pesticide concentrations in water between 20-67%, which improved the quality of irrigation runoff before entering downstream receiving systems. This research is important because it further validates the importance of vegetation in removing pesticides associated with runoff.
Technical Abstract: Irrigation and storm water runoff from agricultural fields has the potential to cause impairment to downstream aquatic receiving systems. Over the last several years, scientists have discovered the benefit of using edge-of-field practices, such as vegetated agricultural drainage ditches, in the mitigation of pesticides and sediment. After demonstrating this practice’s feasibility in an experimental setting, field trials were initiated to document irrigation runoff pesticide mitigation in California alfalfa and tomato fields. In the alfalfa field, chlorpyrifos concentration was decreased by 20% from the inflow to the ditch outflow. Nearly 33% of the pesticide was associated with ditch plant material. In a tomato field, permethrin concentration was decreased by 67% and there was a 35% reduction in suspended sediment concentration from inflow to the ditch outflow. When water was not present in the ditch systems, the sediment was a significant repository for pesticides. In addition to field trials, an economic study was performed to evaluate the cost effectiveness of the vegetated agricultural drainage ditches as management practices. The workbook addresses alternative vegetated ditch configurations for different specifications, as well as basic hydrologic information, installation and operation costs. Based on the field trials and economic study, vegetated agricultural drainage ditches can be successfully used as part of a suite of management practices to reduce pesticide and sediment runoff into aquatic receiving systems.