EFFICACY OF VEGETATIVE FILTER STRIPS TO MINIMIZE SOLIDS AND NUTRIENTS FROM FEEDLOT RUNOFF

Abstract

Runoff from open animal feeding operation is a major source of non-point pollution. Vegetative filter strips (VFS) are one of the effective ways in controlling non-point source pollution. In this study, performance of a vegetative filter strip situated at down slope end of a beef feedlot was evaluated under North Dakota climatic conditions. Two automatic ISCO samplers were installed to collect runoff water entering and leaving the vegetative filter strip. Runoff samples were analyzed for solids, nutrients, pH, and conductivity using standard methods. Results indicated that VFS was effective in reducing concentration of total solids (TS) by 33.7%, total suspended solids (TSS) by 68.0%, total phosphorous (TP) by 29.9%, ortho-phosphorous (OP) by 19.3%, ammonium nitrogen (NH₄-N) by 31.8%, total Kjeldahl nitrogen (TKN) by 35.6%, and potassium (K) by 19.8%. Nitrate nitrogen (NO₃-N) concentrations at the outlet samples increased as expected, and the buffer was not effective in reducing soluble nutrients. Performance of the VFS indicated that a VFS can be used for reducing runoff pollution that comes directly from feedlots into VFSs without passing through the settling basins. Longer buffer lengths might be required for reducing soluble pollutants.