Abstract: The degradative characteristics ofphenanthrene, microbial biomass
carbon, plate counts of heterotrophic bacteria and most probable number (MPN)
of phenanthrene degraders in non-rhizosphere or rhizosphere soils with
uninoculating or inoculating phenanthrene degraders were measured. At the
initial concentration of 20 mg phenanthrene/kg soil, the half-lives of
phenanthrene in uninoculated non-rhizosphere soil, uninoculated rhizosphere
soil, inoculated non-rhizosphere soil, and inoculated rhizosphere soil were
measured to be 81.5, 47.8, 15.1 and 6.4 d, respectively, and corresponding
kinetic data fitted first-order kinetics. The highest degradation rate of
phenanthrene was observed in inoculated rhizosphere soil. The degradative
characteristics of phenanthrene were closely related to the effects of
vegetation on soil microbial process. Vegetation could enhance the magnitude
ofrhizosphere microbial communities, microbial biomass content, and
heterotrophic bacterial community, but barely influence those community
components responsible for phenanthrene degradation. Results suggested that
combination of vegetation and inoculation with degrading microorganisms of
target organic contaminants was a better pathway to enhance degradation of the
organic contaminants in soil.