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ARS Home » Plains Area » Lincoln, Nebraska » Agroecosystem Management Research » Research » Publications at this Location » Publication #266438
Title: Assessing the performance of a vegetative treatment system to reduce pathogens in feedlot runoff

Author
item Durso, Lisa
item Miller, Daniel
item HENRY, CHRISTOPHER - University Of Nebraska

Submitted to: Meeting Abstract
Publication Type: Abstract Only
Publication Acceptance Date: 3/31/2011
Publication Date: N/A
Citation: N/A

Interpretive Summary: When rain falls on a feedlot it gets mixed with animal manure. The feedlot runoff contains manure nutrients and microorganisms that could impact environmental and public health. It is important to keep this feedlot runoff water from contaminating surface and ground water sources. Vegetated Treatment Systems (VTS) are a novel method to treat feedlot runoff from rain events as an alternative to conventional storage systems. Feedlot runoff is collected in an unlined sediment basin, and used to irrigate vegetative treatment areas planted with perennial grasses harvested for hay. We looked at how fecal-indicator bacteria and pathogens like E. coli O157:H7 and Salmonella traveled through the VTA. The number of bacteria in the runoff water collected from the exit of the treatment areas is the same as the number applied to the entrance to the treatment areas. Over time both fecal indicator organisms and pathogens are reduced in the soil matrix. For example, Escherichia coli O157:H7 and Salmonella were cultured from 96% and 85% of runoff samples, respectively, but from less than 1% of the end-of-season soil samples. We conclude that while the VTS does not prevent overland transport of fecal indicators or pathogens at the time of runoff application, the system effectively reduces the concentrations of residual manure-associated bacteria over time This data supports the importance of designing irrigation systems for land application of manures that minimize runoff for limiting pathogen transport.

Technical Abstract: Vegetated Treatment Systems (VTS) are a novel method to treat feedlot runoff. Feedlot runoff was collected in a sediment basin, stored briefly and applied to eight treatment areas comprised of perennial grass vegetation. This system is designed to collect excess applied liquid and return it to the sediment basin (recycle system). Traditional fecal indicator metrics in combination with specific assays for manure-borne human pathogens were used to assess the microbiological quality of the VTS runoff, and the survival of bacteria in the soil. Transport of fecal indicators across the treatment areas did not reduce fecal indicator organism concentrations during application. However residual bacterial concentrations in the soil declined over time, and the soil cores taken at the end of the season indicate a 3-5 log reduction of fecal bacteria in the VTS after repeated frequent application. Escherichia coli O157:H7 and Salmonella were cultured from 96% and 85% of runoff samples, respectively, but from less than 1% of the end-of-season soil samples. We conclude that while the VTS does not prevent overland transport of fecal indicators or pathogens at the time of manure application, the system effectively reduces the concentrations of manure-associated bacteria in the soil over time in the treatment areas. This data supports the importance of designing irrigation systems for land application of manures that minimize runoff for limiting pathogen transport. While a VTS was used in this study, the results have implications for any type of land application from feedlots.