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United States Department of Agriculture

Agricultural Research Service

Title: ON THE EFFECT OF AIR HUMIDITY ON SOIL SUSCEPTIBILITY TO WIND EROSION: THE CASE OF AIR-DRY SOILS

Authors
item Ravi, Sujith - UNIVERSITY OF VIRGINIA
item D'Ordorico, Paolo - UNIVERISTY OF VIRGINIA
item Over, Thomas - EASTERN ILLINOIS UNIVERSI
item Zobeck, Teddy

Submitted to: Geophysical Research Letters
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: March 9, 2004
Publication Date: March 9, 2004
Citation: Ravi, S., D'Ordorico, P., Over, T.M., Zobeck, T.M. 2004. On the effect of air humidity on soil susceptibility to wind erosion: the case of air-dry soils. Geophysical Research Letters. 31:LO9501.

Interpretive Summary: Wind erosion is a widespread process in dry regions of the world. Wind erosion causes a loss of soil fertility and produces air pollution. Erosion occurs when wind speed exceeds a certain value, which depends on a number of factors, including surface soil moisture. We show that in air-dry soils surface moisture and wind speed at which erosion starts depends significantly on the air humidity. Thus, in arid regions variations in surface soil moisture can be significantly affected by changes in atmospheric humidity, with an important effect on the potential for wind erosion to occur. A series of wind tunnel tests were conducted to investigate how the wind velocity needed to start erosion depends on air humidity in air-dry soils. It was found that at these very low moisture levels, the velocity needed for wind erosion decreases with an increase in air humidity. This result is explained by the effect of how water is bound to particles in dry soils

Technical Abstract: Wind erosion is a widespread process in arid and semi-arid regions, and contributes to loss of soil fertility, alteration of atmospheric radiation, and air pollution. Erosion occurs when wind speed exceeds a certain threshold value, which depends on a number of factors, including surface soil moisture. We show that in air-dry soils surface moisture and threshold wind speed depend significantly on air humidity. Thus, in arid regions variations in surface soil moisture can be significantly affected by changes in atmospheric humidity, with an important effect on wind erosion potential. A series of wind tunnel tests were conducted to investigate this dependence of threshold velocity on air humidity in air-dry soils. It was found that at these moisture levels, the threshold velocity decreases with an increase in air humidity. This result is explained by the effect of hygroscopic forces on particle cohesion in dry soils and by their dependence on soil matric potential.

Last Modified: 10/31/2014
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