Submitted to: Proceedings of the National Agricultural Ecosystem Management Conference
Publication Type: Proceedings
Publication Acceptance Date: 12/15/1995
Publication Date: N/A
Technical Abstract: Aquatic systems can be adversely impacted when sediment, nutrients, and pesticides run off agricultural fields. Conservation tillage and filter strips have been recognized as having potential benefit to aquatic systems because of the reduction in sediment load and nutrients and pesticides to the stream. However, there is little understanding of the mechanisms involved in the reduction of pesticides moving through filter strips. Studies have been conducted in Iowa, Nebraska, Missouri, and Texas for three years with the objective to evaluate the mechanisms of pesticide removal from surface runoff moving through a grassed filter strip. Atrazine, cyanazine, and metolachlor were studied in both natural rainfall and simulated runoff conditions at a number of locations. Under natural rainfall conditions, no-till, ridge-till, and chisel-plow tillage reduced herbicide runoff by 70%, 42%, and 69%, respectively. Over all studies, conservation tillage reduced herbicide runoff by 60%. Grassed filter strips reduced herbicides by an average of 48%. It was found that infiltration of surface runoff into the filter strip was responsible for the reduction in herbicide load of the runoff water. When there was large sediment load moving from the fields, the infiltration into the filter strip was less effective. Coupling conservation tillage practices that reduce sediment loss and surface runoff from fields with grassed filter strips can impact the quality of stream water in the United States.