Human and livestock exposure to fecal pathogens via contaminated surface or groundwater is an important water quality concern for soils receiving animal wastes. The effects of manure application timing (spring or fall application) and soil management (no-tillage or conservation tillage) on fecal bacteria infiltration through shallow karst soils in central Kentucky (the Bluegrass region) have not been evaluated. We performed a field experiment to measure fecal coliforms and fecal streptococci in leachate from dairy manure-amended no-tillage and conservation tillage soils. Manure significantly increased fecal bacteria in leachate compared with unmanured treatments. After manure application, the leachate that collected in zero-tension lysimeters 90 cm below the soil surface contained up to 6 × 104fecal coliforms/100 mL and generally exceeded 3 × 103 fecal coliforms/100 mL. Neither the timing nor the tillage method significantly affected fecal coliform concentrations in leachate. Fecal bacteria in leachate declined to nondetectable levels within 60 d of manure application. In the well structured soil used in this experiment, fecal bacteria moved below the crop root zone whenever there was rainfall of sufficient duration or intensity to cause flow after manure application. Manure application to no-tillage soil in spring did not accelerate water contamination by fecal coliforms relative to fall manure applications. No-tillage did not accelerate water contamination by fecal coliforms relative to tilled soils. The potential for groundwater contamination depended on soil structure and water flow more than on fecal bacteria survival at the soil surface.
Digital Object Identifier (DOI)
Stoddard, C. S.; Coyne, Mark S.; and Grove, John H., "Fecal Bacteria Survival and Infiltration through a Shallow Agricultural Soil: Timing and Tillage Effects" (1998). Plant and Soil Sciences Faculty Publications. 9.