Influence of Moisture on Erodibility of Soil by Wind

Abstract This study was undertaken to determine the general influence and the specific quantities of moisture that soils must have to resist wind. Erodibility by wind was about the same for soil that was oven‐dried or air‐dried in sun or in shade when moisture did not exceed one‐third of the 15‐atmosphere percentage. Beyond this range of moisture a distinct decrease in erodibility was manifested. Erodibility decreased rather slowly at first, then more rapidly with each successive increment of moisture added, reaching zero, on the average, at about 15‐atmosphere percentage. Increasing the moisture even slightly above the 15‐atmosphere percentage required a relatively great increase in wind velocity to produce movement of soil. It was shown that erodibility by wind is a function of the cohesive force of adsorbed water films surrounding the soil particles. Equations were derived indicating the relationships between cohesive force due to adsorbed water films, quantity of adsorbed water, and erodibility by wind.