STATUS OF SOIL NUTRIENTS FOLLOWING BIOREMEDIATION OF PETROLEUM CONTAMINATED TALLGRASS PRAIRIE SOILS

Joshua Brokaw*
Oklahoma State University
Botany Department
Life Sciences East 104
Stillwater, OK 74078
Voice: 405-744-5559
Fax: 405-744-7074
E-mail: jbrokaw@okstate.edu

Kerry L. Sublette
Chintan Mehta
Laura Ford
The University of Tulsa
Tulsa, OK

G. Thoma
University of Arkansas
Fayetteville, AR

Kathleen Duncan
University of Oklahoma
Norman, OK

In January 1999 a pipeline break releasing dewatered crude oil contaminated two areas separated by about 100 m at the Tallgrass Prairie Preserve in Osage County, Oklahoma. In May 1999 prairie hay was applied to both areas by tilling. Both areas were divided with corrugated plastic sheeting, and the down-slope sections of each area were fertilized with NH₄NO₃, P₂O₅, and K₂O. One control section of uncontaminated prairie also was tilled with prairie hay. In this study we analyzed soils collected during June 2003 to determine whether significant differences in nitrogen and phosphorus pools persisted in the contaminated sites due to fertilizing and tilling. We collected soil samples from 40 grassland sites within the preserve to provide a replicated control. We found that some soils collected from the contaminated areas exhibited levels of plant-available inorganic nitrogen and phosphorus in excess of the highest levels measured in the replicated control soils. The elevated nutrient availability appears to be related to fertilizer additions and disturbance of the plant communities.