INFLUENCE OF PLANTS ON SOIL COMMUNITY DYNAMICS IN A PETROLEUM-CONTAMINATED SOIL

S.E. Ziegler
University of Arkansas
Department of Biological Sciences
601 Science Engineering Building
Fayetteville, AR 72701
Voice: 479-575-6944
Fax: 479-575-4010
E-mail: susanz@uark.edu

G.J. Thoma
University of Arkansas
Department of Chemical Engineering
Fayetteville, AR

Duane Wolf*
K.M. Greer
University of Arkansas
Department of Crop, Soil, & Environmental Sciences
Fayetteville, AR

Plant growth can influence the composition of the biological community ultimately responsible for the effectiveness of the phytoremediation of petroleum-contaminated soil. The study objective was to evaluate plant shoot and root growth and microbial community dynamics at an oil-spill site that had an initial total petroleum hydrocarbon (TPH) concentration (by GC/FID) of 9,175 mg/kg. Four replications of the following treatments were used: non-fertilized vegetation-free control; ryegrass - fescue mixture + fertilizer; or bermudagrass - fescue mixture + fertilizer. Chemical and biological properties were analyzed at 0, 6, 17, 21, 30, 37, and 42 months after initiation of the field study. Vegetation was successfully established at the site and vegetated fertilized plots had significantly greater reductions in TPH as compared to the non-vegetated non-fertilized control plots. Vegetation establishment and fertilizer addition resulted in increased bacterial and fungal numbers. The results of these studies demonstrate that plants alter the soil biological community and influence clean up of crude oil-contaminated sites.