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ARS Home » Midwest Area » Ames, Iowa » National Laboratory for Agriculture and The Environment » Agroecosystems Management Research » Research » Publications at this Location » Publication #351058

Research Project: Agroecosystem Benefits from the Development and Application of New Management Technologies in Agricultural Watersheds

Location: Agroecosystems Management Research

Title: Assessing pathogen presence in an intensively tile drained, agricultural watershed

Author
item Rieke, Elizabeth - Iowa State University
item Moorman, Thomas - Tom
item Soupir, Michelle - Iowa State University
item Yang, Fan - Iowa State University
item Howe, Adina - Iowa State University

Submitted to: Journal of Environmental Quality
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 7/3/2018
Publication Date: 8/9/2018
Citation: Rieke, E.L., Moorman, T.B., Soupir, M.L., Yang, F., Howe, A. 2018. Assessing pathogen presence in an intensively tile drained, agricultural watershed. Journal of Environmental Quality. 0. https://doi.org/10.2134/JEQ2017.12.0500.
DOI: https://doi.org/10.2134/JEQ2017.12.0500

Interpretive Summary: Increases in swine production in Iowa and the resulting manure application provides beneficial nutrients for crops, but agricultural overland flow and artificial subsurface drainage transport antibiotic resistance genes and excess nutrients to surface waters. However, little information is known regarding the long term effect of manure application on pathogen fate and transport into surrounding waterways. We used DNA sequencing to detect pathogenic bacteria in the agriculturally dominated South Fork of the Iowa River Watershed, home to approximately 840,000 swine in the 187,800 acre basin. DNA was extracted from monthly water samples collected from three surface water sites and two main artificial drainage outlets. DNA sequences from water samples were matched with sequences from known pathogens in DNA databases. Bacterial pathogens were detected from both surface waters and subsurface drainage water and some pathogens were preferentially detected in surface water or drainage water, suggesting different transport pathways. The results of this study will help scientists, conservationists and regulators to understand environmental pathways of pathogen transport in agroecosystems and the risk of pathogen presence.

Technical Abstract: Increases in swine production in Iowa and concomitant manure application provides beneficial nutrients for crops, but agricultural overland flow and artificial subsurface drainage transport antibiotic resistance genes and excess nutrients to surface waters. However, little information is known regarding the long term effect of manure application on pathogen fate and transport into surrounding waterways. We report on the use of 16S rRNA gene sequencing to detect pathogenic bacteria in the agriculturally dominated South Fork Iowa River Watershed, home to approximately 840,000 swine in the 76,000 ha basin. DNA was extracted from monthly grab samples collected from three surface water sites and two main artificial drainage outlets. DNA sequences from water samples were matched with sequences from known pathogens. Specifically, abundances of Bacteroides, Clostridium sensu stricto and Acinetobacter significantly increased in surface water after typical fall manure application timing. Additionally, the likely transport pathways for specific pathogens were identified. Surface water Enterobacter concentrations were influenced mainly by artificial drainage, while Clostridium sensu stricto was primarily transported to surface waters by runoff events. The results of this study will help us to understand environmental pathways which may be useful for mitigation of pathogen transport in agroecosystems.