SOIL AND FECAL-COLIFORM TRAPPING BY GRASS FILTER STRIPS DURING SIMULATED RAIN

Poultry production is increasing in Kentucky. The wastes produced are typically added to soil but surface runoff from agricultural soils tre ated with poultry waste may exceed water quality standards for fecal i ndicator bacteria and contribute to agricultural nonpoint-source pollu tion. While soil erosion in surface runoff is frequently managed by gr ass filter strips, this management practice may not be an equally effe ctive control for fecal bacteria. We measured soil and fecal coliform trapping in surface runoff from two poultry manure-amended plots in a simulated rain study. The simulation reflected a worst-case event in w hich poultry waste application was followed by high intensity rain. Gr ass filter strips, 9 meters long, trapped more than 99% of the soil in surface runoff but fecal coliform trapping was less effective. The ef ficiency of fecal coliform removal from surface runoff was 74% and 43% in the two plots studied. Fecal coliforms in surface runoff always ex ceeded primary contact water standards of 200 fecal coliforms/100 ml. These data indicated that grass filter strips which adequately control led sediment runoff were inadequate to bring surface water contaminate d with fecal bacteria into compliance with current primary water conta ct standards.