EROSION CONTROL ON ROADSIDE EMBANKMENT USING COMPOST

This study explored the potential of using a patent-pending compost as a rainfall and wind erosion control blanket oil roadside embankments. A rainfall simulator was constructed to simulate natural rainfall. A soil box was designed and built to accommodate the erosion tests. A sandy loam soil was used as the embankment base soil, and the compost of four different pellet sizes made primarily from cattle manure was applied on the base soil as a surface erosion control blanket. Two compost combinations were tested: (1) filtered compost - composts of three different pellet sizes were laid oil the upper one-third, the mid one-third, and the lower one-third sections of the slope, respectively, with finer compost on the upper slope and coarser compost oil the lower section of the slope; (2) mixed compost - compost of different particle sizes were mixed together and applied oil the base soil. Both configurations were tested under repeated rainfall to evaluate the long-term erodibility. Grasses were seeded in the two combinations to study the germination in the compost and the rainfall erosion resistance of vegetated compost. Experimental results showed that the compost cover in the above configurations significantly reduced soil loss, and the soil loss of the mixed compost with vegetation was within the tolerable limit (5 tons/acre/yr) specified by, the U.S. Natural Resources Conservation Service. Vie runoff was analyzed for its physical and chemical constituents in order to evaluate the environmental impact of the compost application. Wind erosion tests oil both the base soil and compost were conducted in a wind tunnel at a U.S. Department of Agriculture facility. A method to estimate the erodibility factor of compost was proposed. This preliminary study showed the potential of this proprietary compost as an effective erosion control material