ABSTRACT:
Soil surface aggregates (random roughness) and ridges (oriented roughness) can reduce soil loss by wind erosion. The soil roughness factor used in the Wind Erosion Equation (WEQ) model describes the effect of soil roughness on soil loss by wind. However, the soil roughness factor used in the WEQ does not include the random roughness effect, decay of soil surface roughness by rainfall, and is described only for the direction perpendicular to the ridges. This study was conducted to develop a new soil roughness factor for the Revised Wind Erosion Equation (RWEQ) model. The new soil roughness factor (K') (1) includes both oriented and random roughness effect; (2) is modified as soil surface roughness decay by rainfall; and (3) is predicted at any given angle with respect to ridge orientation. Wind tunnel data were used to generate K' which includes the effect of both random and oriented roughness. Surface roughness decay functions were used to predict K' when soil surface is decayed as function of rainfall amount and storm erosivity index (EI). A function was used to predict K' at any given angle with respect to ridge orientation for ridged fields.
Footnotes
Ali Saleh is a research scientist at the Texas Institute for Applied Environmental Research, Tarleton State University, Stephenville, Texas; and D. W. Fryrear is research engineer for Custom Products and Consultants, Big Spring, Texas. Both authors had worked for the U.S. Department of Agriculture Agricultural Research Service in Big Spring.
- Copyright 1999 by the Soil and Water Conservation Society
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