John P. Brooks, USDA-ARS, Waste Management & Forage Research Unit, 810 Hwy 12 East, Mississippi State, MS 39762, Ardeshir Adeli, USDA-ARS Invasive Weed Management Research Unit, USDA-ARS Waste Mngmnt & Forage, 810 Hwy 12 East, Mississippi State, MS 39762, and Dennis Rowe, Experimental Statistics, Mississippi State University, Mississippi State, MS 39762-5367.
Poultry rearing in the United States is approximately a thirty million dollar per year industry. Land application of poultry litter is an economical viable use of this manure byproduct. However the recent concern associated with organic food and pathogenic bacterial contamination has led to increased scrutiny regarding land applied manures. Runoff following a rain event is one possible source of environmental contamination resulting from manure application. In this study a series of treatments involving litter (two rates), inorganic fertilizer, and no fertilizer controls were added to bermudagrass troughs held in a greenhouse environment. A rainfall simulator was used to simulate precipitation events and following each rain event, runoff samples were collected for microbial analysis. Total Heterotrophic Plate Count bacteria, antibiotic resistant bacteria, fecal coliforms, enterococci, staphylococci, and Clostridium perfringens were investigated. Over a period of 25 days, 5 rain events were simulated and results indicated that staphylococci, enterococci, and clostridia correlated directly with manure application. Traditional indicators such as thermotolerant and total coliforms performed poorly as fecal indicators relative to the other bacteria assayed in this study. This study demonstrated that poultry litter can contribute to significant microbial runoff following land application and C. perfringens can be used as a reliable indicator of runoff.