Wind Erosion in Western Queensland Australia

Chapter 2 – Land Erodibility ControlsFigure 2.5 Diagram illustrating the dependence of soil textures on drought to experience a significantincrease in soil erodibility. The dependence of clay textured soils on drought is due to the requirementfor long dry periods that enable the breakdown of aggregates to occur (after Gillette, 1978)Soil Aggregation Effects on Wind ErosionSoil aggregation affects wind erosion by increasing the surface roughness length (z 0 ),decreasing the availability of loose erodible material, and increasing the wind shear velocityrequired to mobilise grains (u *t ). Aggregation also plays a role in fine particle emissions, withaggregate size and stability affecting the impact energy of saltating particles and the potentialfor abrasion to occur (Zobeck, 1991).Chepil (1942) and Chepil and Woodruff (1954) reported on the use of dry aggregate structureto rank soil erodibility. They identified that the dry aggregate component of a soil >0.84 mmin diameter is typically non-erodible. This component drives the availability of loose erodiblematerial (grains