Submitted to: Agricultural Engineering International Conference
Publication Type: Abstract Only
Publication Acceptance Date: February 27, 2002
Publication Date: June 25, 2002
Citation: Roodsari, R., Shelton, D.R., Sadeghi, A.M., Pachepsky, Y.A., Starr, J.L., Shirmohammadi, A. 2002. Pathogen transport affected by surface conditions. Agricultural Engineering International Conference Proceedings. p.131.
A two-sided lysimeter set-up with 20% slope on both sides was instrumented to monitor the surface and vertical transport of pathogens. Each side of the lysimeter includes two sub-plots (6.7 m x 7.3 m), one is grass-covered and the other is bare soil. Each of the four plots was instrumented to collect surface samples along the 6.7 m slope transect at three different rows. In addition, samples were collected at the gutter that was installe at the edge of each plot. All the plots were equipped with multi-sensor moisture probes to monitor real-time water content through the soil profile. Bovine manure was applied at the top of the slope of each plot in strip of 25 cm. Rainfall was simulated at a 60mm/hr using a portable rainfall simulator on each plot. Flow was measured and samples were taken both on the surface at different transects and at different depths in the top 50 cm of the soil profile. Samples were analyzed for fecal coliform counts at each sampling site. Data on fecal coliform counts indicated tha while 100% of the initial population was lost to runoff from bare plots, only 3.8% of the initial population was lost from grassed plots. Data also showed that the fecal coliform count decreased with distance, with the highest counts being observed at the top of the plots. Furthermore, bare plots offer no resistance to flow and thus lag time between observing bacteria at the top of the plot and that at the gutter (weir) was very small.