Submitted to: American Water Resources Association Conference Proceedings
Publication Type: Abstract Only
Publication Acceptance Date: 2/3/2014
Publication Date: 3/13/2014
Citation: Borchardt, M.A., Spencer, S.K., Jokela, W.E. 2014. Surface runoff from manured cropping systems assessed by the paired-watershed method, part 2: pathogen transport. American Water Resources Association Conference Proceedings. March 13-14, 2014.
Technical Abstract: Manure application to cultivated land is a sustainable approach for enhancing soil fertility and tilth. However, pathogens are common in manure and can be transported from application sites via runoff and potentially transmitted to livestock and humans. Our objective is to quantify a diverse group of bovine and zoonotic pathogens in surface runoff from field-scale sites, to which dairy manure is applied. A 6.4 hectare field located in central Wisconsin was divided by drive-through berms into four 1.6 ha fields so that each has a single drainage point. The fields have 1-3% slope and are cropped annually in corn. Manure (56,000 L/ha) is applied once per year. Runoff stations are equipped with 60-cm H-flumes, flow meters, and automated samplers. Samples are analyzed for enteric pathogenic protozoa, bacteria, and viruses by qPCR and for indicator E. coli by chromogenic assay. Treatment effects (i.e., different manure/cropping systems) on pathogen runoff are being evaluated by the paired-watershed method. Pathogen types and concentrations in the applied manure and subsequent runoff were highly variable by year. Runoff continued to contain pathogens many months after manure application. Indicator E. coli was not correlated with pathogen levels. Estimated pathogen export ranged from 0.001% to 7% of the pathogen load applied to the land surface via manure. These data are valuable for identifying best management practices for reducing pathogen transport from agricultural sites and for assessing health risk to livestock and humans.