Submitted to: Journal of Water and Health
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 9/2/2012
Publication Date: 10/1/2012
Citation: Brooks, J.P., McLaughlin, M.R., Adeli, A., Miles, D.M. 2012. The effect of poultry manure application rate and AlCl3 treatment on bacterial fecal indicators in runoff. Journal of Water and Health. 10:619-628.
Interpretive Summary: Land application of poultry litter is a beneficial method of using this fertilizer source. It can provide high levels of N and organic C. However, the protection of water sources following land application of any fertilizer is necessary since many of the US surface water supply has been compromised due to the presence of fecal bacteria like Escherichia coli (E. coli) or anoxic, a condition in which the presence of nutrient runoff can lead to conditions which kill fish. The purpose of this study was to determine a suitable fecal indicator for poultry litter runoff following large-scale rain events. A previous greenhouse study determined that there are other poultry-litter fecal indicators more suitable for runoff than traditional indicators such as E. coli; this study confirms those results and found that of all treatments receiving poultry litter, two indicators proved to be useful. Over a two year period, field plots were land applied with various combinations of poultry litter or inorganic fertilizers and rained upon with an artificial rain maker. The results suggested that Clostridium perfringens and staphylococci were more useful as an indicator of poultry litter horizontal movement than all others. This persisted for up to 30 days following land application of poultry litter. The presence of these two indicators may signal a change for regulators and environmental monitors when investigating poultry litter fecal pollution.
Technical Abstract: The land application of poultry litter was once considered to be the disposal of a ‘waste’ byproduct of the poultry industry, however, now due to increasing costs associated with inorganic fertilizer the application of this residual is becoming more desirable. Proper land application is paramount to surface water protection from microbial and nutrient runoff. This study was designed to validate and confirm greenhouse findings which suggested the use of alternative indicators of poultry litter runoff. Field runoff studies were conducted throughout two years in which field plots were applied with N and P based litter, fertilizer, and control treatments (year 1); N and two variable N+AlCl, and control treatments (year2), and rained on five times per year using an artificial rain generator. Runoff was generated and processed for microbial parameters. Overall, total microbial runoff from each set of plots produced microbial release in which poultry litter applied plots were consistently greater (2-5 log10) in indicator release. Clostridium perfringens and staphylococci releases were consistently associated with poultry litter application, particularly during the first 3 rain events (<30 days following application). These field studies suggested that poultry litter application may be able to be traced and source tracked with alternative fecal indicators such as C. perfringens or staphylococci as opposed to traditional Escherichia coli or enterococci. These findings may be of use for regulatory or public health protection, where the use of E. coli has failed to be an adequate indicator of fecal contamination of surface waterways following a rain event.