Vegetation is commonly used to stabilize the ground covering buried waste sites.^However, constituents of buried waste can be brought to the surface if the waste is penetrated by plant roots.^An ideal waste burial system would allow the use of vegetation to stabilize the soil above the buried waste but would exclude roots from the waste.^One system which shows promise of accomplishing this objective is a root biobarrier.^The biobarrier consists of a slow release encapsulation of a root growth inhibitor (Trifluralin).^The capsules are bounded on a geofabric sheet.^Tests were conducted in a rhizotron and in the glass walled trenches in the field to observe the effect of the root biobarrier on the growth of a variety of plant species.^The preliminary results indicate that roots of soybean (Glycine max (L).^Merr.) and Bermuda grass (Cynodon dactylon (L).^Pers.) do not grow within one inch of the barrier.^Analysis of the level of root inhibitor in the soil confirms that the concentration of inhibitor near the biobarrier is high enough to stop root growth.^If further tests continue to show that the biobarrier can exclude roots for extended periods of time it appears the biobarrier should be considered for inclusion in buried waste systems.

"DP-1767." "UC-702." "August 1988." Bibliography: p. 16.