Computing the wind erodible fraction of soils

ABSTRACT: Chepil, Woodrufi and Siddoway, developers of the wind erosion equation (WQ), suggest that the wind erodible fraction of any soil can be determined by dry sieving a sample of the surface soil. The data base of soil information for the wind erosion equation was primarily from the Central Great Plains. As other areas used the WQ, questions about the erodible fraction based on soil texture alone began to surface. To test soils outside the Great Plains, more than 3,000 samples have been sieved to identify the relationships between the erodible fraction of soils and the physical and chemical properties of the soil. From these results, the erodible fraction was computed from the percentage of sand, percentage of silt, sand/clay ratio, organic carbon, and calcium carbonate. A correlation coefficient of 0.82 was obtained between computed erodible fraction using soil physical and chemical properties with average measured erodible fraction from standard compact rotary sieving from sites with at least 20 samples. The erodible fraction of dryland soils was reduced an average of 14% and of irrigated soils 24% with moldboard plowing