Concentrations of fecal bacteria and nutrients in soil surrounding round-bale feeding sites1,2

Abstract

An experiment was conducted over 7 mo (January to July 2003) to evaluate fecal bacteria and nutrient concentrations in soil surrounding round-bale feeders at 10 winter feeding sites. Soil samples 15 cm in depth were taken monthly from each site at distances of 3, 12, 21, and 30 m from the feeder. Soil samples were taken before livestock access to the sites (January), during the feeding period (February, March, and April), and after cattle removal from the sites (May, June, and July). Results indicated that fecal bacteria concentrations increased over the feeding period and were greatest at close proximity to round-bale feeders. Fecal Escherichia coli concentrations were greater in April (P < 0.03) at 3 and 12 m than in all other months, except March. At 21 and 30 m from the feeders, fecal E. coli concentrations were greater in April (P < 0.01) than in other months. At 3 m from the feeder, fecal Streptococci concentrations were greater in March and April (P < 0.01) than in other months. Although fecal E. coli concentrations in July had returned to levels similar to those in the prefeeding period, fecal Streptococci remained at higher concentrations (P < 0.05) than at the prefeeding period. The concentration of soil P at 3 m was greater in April (P < 0.02) than in January, February, and May. After cattle access to the sites, soil DM content was consistently less for samples taken at 3 m from the feeder compared with the other distances, with quadratic decreases (P < 0.02) noted in March, April, and July, and linear decreases (P < 0.01) in May and June, as distance from the feeder decreased.