Wind Erosion in Western Queensland Australia

Chapter 2 – Land Erodibility ControlsThere is a tendency for erodibility factors to deviate from the assumptions and formaldefinitions of erodibility presented by Houghton and Charman (1986) and Bryan et al.(1989). This has arisen from authors creating new definitions of the term to suit particularstudies. For example, while the soil erodibility factor (I) holds to the definition of erodibility(Houghton and Charman, 1986), the field erodibility factor (E) could be defined as a measureof wind erosion hazard. While Geeves et al. (2000) note that the factor is a contradiction toerodibility definitions, nearly all other ‘erodibility’ indices developed since could also beconsidered to be so.The United States Department of Agriculture (USDA) developed the Wind ErodibilityGroups (WEGs) to provide a ranking of the erodibility of soils. The scheme was based onwind tunnel experiments conducted by Chepil (1953) and Zingg (1951). The WEGs rank theerodibility of soils based on surface textural characteristics and an assigned wind erodibilityindex (Table 2.2).Table 2.2 Wind Erodibility Groups and Wind Erodibility Index for soils in the United States (afterSkidmore et al., 1994).WEG Soil Description Wind ErodibilityIndex (t/ha)1 Very fine sand, fine sand or coarse sand 6592 Loamy very fine sand, loamy fine sand, loamy sand, loamycoarse sand or sapric soil materials3 Very fine sandy loam, fine sandy loam, sandy loam orcoarse sandy loam4 Clay, silty clay, non-calcareous clay loam or silty clay loamwith more than 35% clay content3001931934LCalcareous clay loam and silt loam or calcareous clay loamand silty clay loam1935 Non-calcareous loam and silt loam with less than 20% claycontent or sandy clay loam, sandy clay and hemic organicsoils6 Non-calcareous loam and silt loam with more than 20%clay content or non-calcareous clay loam with less than35% clay content7 Silt, non-calcareous silty clay loam with less than 35% claycontent and fibric organic soil material126108858 Soils not susceptible to wind erosion 028