Effect of Initial Soil Moisture Conditions on Runoff Transport of Manure-borne Pathogens through Vegetated Filter Strips

Abstract

Pollution of drinking and recreational water supplies with manure-borne pathogenic bacteria through surface runoff from agricultural lands is a public health threat, particularly, where there is concentrated animal production (e.g., Iowa). This study was conducted to investigate the effect of initial soil moisture conditions on the effectiveness of vegetated filters strips (VFS) to mitigate surface runoff transport of two surrogate pathogenic bacteria, Escherichia coli and Salmonella enterica enterica Typhimurium, from land-applied swine slurry. A 5% slope lysimeter containing clay loam soil was constructed, partitioned into vegetated and bare plots, and the plots instrumented to collect, measure, and sample runoff at different time intervals and at two distances from the slurry application area during rainfall simulations. Results indicated that the potential of VFS to attenuate runoff transport of pathogens was reduced under increased initial soil moisture conditions, indicating that infiltration is an important factor in the mitigation process.