MADISON, WI, June 21st, 2010 Water runoff from cropped farm fields can contain large amounts of eroded soil as well as some of the fertilizer and herbicide. Expanding on existing conservation practices, a team of scientists has tested whether compost filters socks in grassed waterways would reduce sediment flow and retain dissolved chemicals in runoff. The researchers observed reduced sediment in a non-tilled field and reduced concentrations of two herbicides.
Compost filter socks are mesh tubes filled with composted bark and wood chips. These devices have been approved by the U.S. Environmental Protection Agency for use at construction sites as an alternative to silt fences and bales of straw, but have not been tested in agricultural fields.
The two year field study was conducted by USDA-ARS soil scientists Martin Shipitalo and Lloyd Owens, along with hydraulic engineer Jim Bonta and Ohio State University collaborator Libby Dayton. They found that filter socks reduced sediment concentration by 49% in runoff from the tilled field, but had no effect for the no-till field, where sediment concentrations were already 1/5 of that from the tilled field. The filter socks also reduced the concentrations of the herbicide alachlor by 18% and the herbicide glyphosate (Roundup) by 5% in runoff from the tilled field. The filter socks had a negligible effect on nutrient concentrations in the runoff.
Their report was published in the May-June 2010 issue of the Journal of Environmental Quality, published by the American Society of Agronomy, the Crop Science Society of America, and the Soil Science Society of America. It was conducted at the USDA-ARS's North Appalachian Experimental Watershed near Coshocton, OH.
Conservation tillage practices, sometimes referred to as "no-till," leave some of the residue from the previous crop on the soil surface, help reduce the amount of sediment lost in runoff, but do little to reduce the concentra
|Contact: Sara Uttech|
American Society of Agronomy