干旱区生态环境知识资源中心

Disturbance of lacustrine and alluvial soils could increase aeolian dust emissions in the eastern Great Basin, but little is known about the susceptibility of these land surfaces to wind erosion. Threshold friction velocity (u(*t)), a necessary parameter to estimate wind erosion potential, is difficult to accurately measure; methods to estimate u(*t) from alternate measurements would be useful. We measured u(*t) and sediment production rate with a portable wind tunnel, and quantified relationships between u(*t) and eleven easier-to-measure soil surface properties for both undisturbed and disturbed lacustrine and alluvial soils in Snake Valley, Utah. Soil surface type and disturbance significantly influenced u(*t), sediment production rate, and the relationships between u(*t) and easier-to-measure soil surface properties. Only soils with surficial rock fragments and weak physical crusts reached u(*t) before disturbance, whereas all surface types reached u(*t) following disturbance. Soils with weak physical crusts had the lowest average u(*t) and highest average sediment production rate before and after disturbance. Surprisingly, however, disturbance reduced sediment production rate. Soils with weak physical crusts and surficial rock cover are likely the most susceptible to wind erosion and subsequent dust generation both before and after disturbance. Silt concentration and penetrometer resistance were significant predictors of u(*t) in undisturbed soils with weak physical crusts and surficial rock cover. Following disturbance, clay concentration and aggregate stability were significant predictors for soils with hard salt crusts and surficial rock cover. Prediction of u(*t) using alternate measurements is promising, but u(*t) measurement uncertainty must be considered. (C) 2015 Elsevier B.V. All rights reserved.