Vegetation characteristics and soil loss by wind

ABSTRACT: In a laboratory wind tunnel study the relationship between soil loss; wind velocity; and the number, height, and diameter of plant stalks was determined. Wood dowels were used to simulate standing vegetation. The dowels protruded above the soil surface and were placed in a removable tray for testing in the wind tunnel. Tests were performed with dowels 3 mm (.12 inch) or 7 mm (.28 inch) in diameter and 50, 150, or 250 mm (2, 6, or 10 inches) tall. The number of stalks tested varied from 20 to 400 stalks/m2 (1.9 to 37 stalk d square foot). Soil loss from the “vegetated” tests was compared to soil loss from a bare soil. Adjusting free-stream velocity (Uh) for threshold conditions (Ut) and using density (N), diameter (D), and height (H) of the dowels, 82% of the variation in soil loss (SL) could be explained by the equation SL = −3.396% + 298 (Uh-Ut)/(NDH). The results illustrate that even sparse standing vegetation can significantly reduce soil loss.