Submitted to: Journal of Geophysical Research
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: July 9, 1998
Publication Date: N/A
Interpretive Summary: Understanding the potential of soils to emit dust can help improve soil management to control wind erosion. We gathered soil samples from the Lubbock, Texas area and generated fine dust from them in our laboratory. The dust we made inside our lab is like a dust storm outdoors. The most dust was released by unpaved roads and three types of soil (sandy clay, sandy clay loam, and loam). Although sand is vulnerable to wind erosion, it gives off less dust than most other soils. EPA air quality models predict that blowing dust levels are related to how much silt is in the soil. While this was true in our test, other soil properties were even better related to the amount of dust.
Technical Abstract: A better knowledge of the role of sedimentary texture in dust emissions from different surfaces can improve our understanding of aeolian processes and the effect of mineral aerosols on cimate. We sampled wind-erodible sediment from agricultural soils, sand dunes, playa surfaces, and unpaved road surfaces in the Southern High Plains near Lubbock, Texas, USA, a region of active aeolian processes. Dust was generated and collected fro the samples under controlled laboratory conditions. Results are expressed in terms of an instrument-specific "dustiness index" (mass of aerosols less than or equal to 10 um aerodynamic diameter [PM10] collected per gram of sediment per minute). The largest dustiness index (mean = .0050 mg/g/min) was found for unpaved road surfaces, sandy clay, sandy clay loam and loam soils. These sediments produced more PM10 than sandy loam and loamy sand soils (.0035 mg/g/min), while sand (.0012 mg/g/min) and clay (.0004 mg/g/ min) soils produced less PM10. "Dustiness" of soils was related to their textural characteristics and other physiocochemical properties; PM10 emissions were most strongly correlated to clay content and the total content of particles less than or equal to 100 um (clay, silt and very fine sand) in these soils. Dustiness indices of unpaved-road and roadside-ditch materials were not significantly correlated to any textural characteristics we measured. Cropping system had no significant effect on the intrinsic "dustiness" of soils near Lubbock, although soil management can affect dust production in other ways. Dust particles generated in the laboratory typically had multimodal size distributions with maxima in the PM10 and medium silt ranges, matching what has been observed for many dust suspensions measured in the natural environment.