Use of Hardwood Bark Mulch for Highway Slope Stabilization1
- D. J. Osborne and
- W. B. Gilbert2
Many studies have indicated the utility of mulching of bare roadbanks to enhance cover production and reduce runoff and erosion. The objective of this study was to determine the suitability of shredded hardwood bark as a replacement for the conventional straw-asphalt mulch. Bark mulch was used for seeding tall fescue (Festuca arundinacea L.) during “off season” summer months; in addition, plots were mulched with bark in the summer and left unseeded until fall when they were hydroseeded with tall fescue and fertilizer. Field plot tests were conducted in each physiographic province of the state on Porters loam (fine-loamy, mixed, mesic Humic Hapludults), Cecil and Mayodan sandy loam (clayey, kaolinitic, thermic Typic Hapludults), and Norfolk sandy loam (fine-loamy, siliceous, thermic Typic Paleudults). Plots were prepared with conventional tillage equipment to meet state specifications. Shredded hardwood bark mulch was applied with a modified mulch blower at 66 m3/ha. Stand density of tall fescue tillers per square decimeter was evaluated by quadrat counts. Results indicate that in general, the more favorable the environment for tall fescue production, the better the stand density with any one treatment. Under cool temperature and frequent rainfall, no differences were noted. These experiments demonstrated that highway slopes may be mulched with shredded hardwood bark and left unseeded until optimum fall seeding date with adequate erosion control, obviating the need for recultivation currently used to establish permanent cover after a “temporary seeding” during the summer.Please view the pdf by using the Full Text (PDF) link under 'View' to the left.
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