Wind Erosion in Western Queensland Australia

Chapter 2 – Land Erodibility Controlswhere the Q is the transport rate (gm -1 s -1 ) and the constants a, b, and c have the values 4.8, -5.1 and 0.09 respectively. The relationship indicates that clay content up to 15% is extremelyimportant in lowering erosion rates. A minimum erosion rate was found at ~27% clay. Soilswith higher clay content tended to show an increase in erodibility. Similar expressions werereported by Leys et al., (1996) in a comparison of cultivated and non-cultivated soils. In thatstudy, Leys et al. (1996) found that the empirical constants a, b and c were different for thetwo soil treatments, reflecting a breakdown in surface structure due to disturbance (seeChapter 4 for details). The effects of this were seen in both increased erosion rates fordisturbed soils, and an alteration of the rate of change in erodibility in response to a change insoil clay content (Figure 2.4).Figure 2.4 Graph illustrating the effect of soil clay content on sediment transport for soils in cultivated(disturbed) and non-cultivated (crusted) conditions (after Leys et al., 1996).Ultimately, the effect of soil texture on soil erodibility is in determining the potential forcoarse grain binding by finer silts and clays (Chepil, 1953). The effect of increasing the40