Influence of Livestock Manure Type on Transport of Escherichia coli in Surface Runoff

Abstract

Abstract Since livestock manure type may influence transport of Escherichia coli (E. coli) in runoff, the choice of which type of livestock manure to apply to cropland may be a potential beneficial management practice (BMP) to reduce and manage E. coli in runoff. Four common manure types (beef, dairy, chicken, hog) were applied to a clay loam soil in small runoff boxes, and a rainfall simulator was used to generate artificial runoff. Runoff samples were collected at three successive time intervals (0 to 5, 5 to 15, 15 to 30 min) and analyzed for flow-weighted mean concentrations (FWMC) of E. coli as well as mass loss of E. coli expressed as a percentage of total E. coli applied. Manure treatment had a significant (p ≤ 0.10) influence on FWMC of E. coli in runoff. The FWMC of E. coli in runoff for the dairy (33.3 CFU per 100 mL) treatment was similar to the control (3.2 CFU per 100 mL), but E. coli concentrations for the beef (955 CFU per 100 mL), chicken (1,134 CFU per 100 mL), and hog (368 CFU per 100 mL) treatments were all significantly greater than the control. The FWMC values were not significantly different among the four manured treatments except for dairy versus chicken manure, where values were significantly lower for dairy manure. Concentrations of E. coli were less than the guideline for recreation waters (< 200 CFU per 100 mL) for the control and dairy treatment, but exceeded this guideline for beef, chicken, and hog manures, suggesting that dairy manure may be better than the other three manures for protecting surface water bodies for recreational use. Our study suggests that manure type may be a possible BMP to manage and control FWMC of E. coli in surface waters.