Submitted to: Letters in Applied Microbiology
Publication Type: Peer reviewed journal
Publication Acceptance Date: 1/6/2005
Publication Date: 6/23/2005
Citation: Stout, W.L., Pachepsky, Y.A., Shelton, D.R., Sadeghi, A.M., Saporito, L.S., Sharpley, A.N. 2005. Runoff transport of fecal coliforms and phosphorous released from manure in grass buffer conditions. Letters in Applied Microbiology. (41):230-234. Interpretive Summary: Animal manures can contain a variety of human gastrointestinal pathogens. Runoff from manures can potentially result in the contamination of potable or recreational waters. One strategy for minimizing pathogen runoff from manures is the use vegetative filter strips. The efficacy of vegetated filter strips in removing microorganisms from manure runoff, however, is largely unknown. By comparison, much more is known regarding the efficacy of vegetated filter strips in minimizing phosphorous runoff from manure. Consequently, if manure-borne microorganisms and phosphorous behave similarly, previous data regarding phosphorous transport can be applied to microorganisms. Runoff studies were conducted in soil boxes (1 to 3 meter length) planted with grass to simulate vegetated filter strips. Manure was applied at the top of the boxes and rainfall applied. Runoff samples were analyzed for phosphorous and fecal coliform bacteria (indicators of fecal contamination). Overall, the data indicated that phosphorous and fecal coliform transport over/through simulated vegetated buffer strips were highly correlated with on another. These results suggest that, at least over relatively short distances and under saturated conditions where infiltration is limited, information from phosphorous studies may be useful in predicting microbial runoff from manure.
Technical Abstract: Vegetative filter strips have been widely adopted as a conservation measure to decrease edge-of-field losses of both manure-borne microorganisms and P to surface water. There is little information, however, on whether filter strips can effectively decrease both microorganism and P transport in surface runoff. The objective of this work was to test the hypothesis that fecal coliform and P are transported similarly in surface runoff through the vegetative filter strip after being released from land-applied manure. The Hagerstown soil was packed into 18 boxes that were 10 cm deep, 30 cm wide and 100, 200, or 300 cm long. Grass was grown in boxes for 14 weeks prior experiments. The boxes of the same length were placed under the rain simulator and slightly tilted to have different slopes. Manure was broadcast on the upper 30-cm section of each box. Rainfall of was simulated for one hour, and runoff samples were collected for analysis of Cl, fecal coliform (FC), and total P. Percentages of fecal coliforms and P recovered in runoff were similar. The ratio FC:P tended to increase as the distance and the slope increased, although the effects of distance and slope on this ratio were small within the range of slopes and distances in this work. Overall, our data suggest that FC and P transport through simulated vegetated buffer strips are highly correlated with on another, at least over relatively short distances and under saturated conditions where infiltration is limited.