HR: 0800h
AN: B41D-0233    [Abstracts]
TI: Enhancement of wind erosion by fire-induced water repellency in soils: a wind tunnel study
AU: * Ravi, S
EM: sujith@virginia.edu
AF: Department of Environmental Sciences, University of Virginia, 291 McCormick Rd, Charlottesville, VA 22903-4123 United States
AU: D'Odorico, P
EM: paolo@virginia.edu
AF: Department of Environmental Sciences, University of Virginia, 291 McCormick Rd, Charlottesville, VA 22903-4123 United States
AU: Herbert, B
EM: herbert@geo.tamu.edu
AF: Department of Geology & Geophysics, Texas A & M University, M.T. Halbouty Building, College Station, TX 77843-3115 United States
AU: Zobeck, T
EM: tzobeck@lbk.ars.usda.gov
AF: Wind Erosion and Water Conservation Research Unit, USDA, ARS, 3810 4th Street , Lubbock, TX 79415 United States
AU: Over, T M
EM: tmover@eiu.edu
AF: Department of Geology/Geophysics, Eastern Illinois University, 600 Lincoln Ave, Charleston, IL 61920 United States
AB: Wind erosion and fire occurrences are known to affect the composition and structure of vegetation in dryland landscapes. Fires contribute to determine the dominance or co-dominance of woody plants and grasses in arid and semiarid ecosystems. Fires expose the soil surface to the erosive action of wind and also make the soil more erodible by the release of water repellent compounds from vegetation due to burning. Despite the relevance of wind erosion and fires to the dynamics of arid ecosystems, the interactions between these two processes remain poorly understood. Here by a series of wind tunnel experiments, laboratory methods and theoretical analysis, we investigate the effect of fire-induced water repellency on the soil susceptibility to wind erosion. The experiments were done using pure Ottawa sands which were artificially coated with palmitic acid, a common water repellent lipid in soils. The results indicate that fire-induced water repellency enhances soil erodibility, causing a drop in wind erosion threshold velocity. The results are explained by the effect of water repellent compounds on soil-water contact angle and on the strength of interparticle wet-bonding forces.
DE: 1809 Desertification
DE: 1815 Erosion
DE: 1866 Soil moisture
SC: Biogeosciences [B]
MN: Fall Meeting 2005