Fig. 2. Percent decline in colony forming units (CFU) of three microbial strains with two different antibiotics. Values are means over two soils, five different antibiotic concentrations, and two different growth conditions. Bars with same letter are not significantly different at p = 0.05. Salmonella^R, antibiotic resistant strain of Salmonella sp.; Salmonella^S, antibiotic sensitive strain of Salmonella sp.