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Aeolian sediment transport occurs as a function of, and with feedback to ecosystem changes and disturbances. Many desert grasslands are undergoing rapid changes in vegetation, including the encroachment of woody plants, which alters fire regimes and in turn can change the spatial and temporal patterns of aeolian sediment transport. We investigated aeolian sediment transport and spatial distribution of sediment in the surface soil for 7 years following a prescribed fire using a multiple rare earth element (REE) tracer‐based approach in a shrub‐encroached desert grassland in the northern Chihuahuan desert. Results indicate that even though the aeolian horizontal sediment mass flux increased approximately three‐fold in the first windy season in the burned areas compared to control areas, there were no significant differences after three windy seasons. The soil surface of bare microsites was the major contributor of aeolian sediments in unburned areas (87%), while the shrub microsites contributed the least (<2%) during the observation period. However, after the prescribed fire, the contribution of aeolian sediments from shrub microsites increased considerably (∼40%), indicating post‐fire microsite‐scale sediment redistribution. The findings of this study, which is the first to use multiple REE tracers for multi‐year analysis of the spatial and temporal dynamics of aeolian sediment transport, illustrate how disturbance by prescribed fire can influence aeolian processes and alters dryland soil geomorphology in which distinct soils develop over time at very fine spatial scales of individual plants. Plain Language Summary: In this study, we investigated how soil and nutrients attached to soil particles are transported and redeposited by wind after a prescribed fire using a new tracer method in a desert grassland. Results from this long‐term (7‐years) experiment in a desert grassland in the northern Chihuahuan desert reveal the role of fire in changing the erosional and depositional areas on the soil surface, which in turn determine what vegetation type can dominate the landscape. In a grassland encroached with shrubs, prescribed fire modified soil erosion processes and resulted in a more uniform distribution of nutrients in the landscape, favoring grass recovery. The findings also highlight the role of prescribed fires as an effective grassland management tool. Key Points: First long‐term analysis of post‐fire aeolian sediment transport using multiple rare earth element tracersAeolian transport, fires, and vegetation modify surface processes in which distinct soils develop at very fine spatial scales of individual plantsDemonstrates long‐term changes in the post‐fire shift in aeolian sediment source and sink dynamics in heterogeneous dryland landscapes [ABSTRACT FROM AUTHOR]

The article reports on the effects of slope and slope position on local and upstream fluid threshold friction velocities. It states that dunes are common aeolian landforms in deserts. In this study, a computational fluid dynamics (CFD) is employed to simulate a stable wind blowing over slope beds of differing height and coupled with the slope-compensating fluid threshold friction velocity formula. Moreover, based on the CFD model, quantitative analysis of slope gradient and particle position on the initiation of particle movement are performed. Results showed that the slope has a great influence on particle saltation in the windward slope.

Abstract: Wind erosion has degraded over one-half billion hectares of land worldwide. 137Cesium (137Cs) has been used as a tracer to study long-term rates of soil redistribution by water and, to a lesser extent, by wind. Early studies assumed that the decline in 137Cs activity for a potentially eroded soil relative to that for an uneroded soil was linearly proportional to soil loss. More recently, models have emerged that consider the effects of soil cultivation and the particle surface area-dependent partitioning of 137Cs on soils. We investigated the partitioning of 137Cs in wind-eroded sediments and with soil surface samples sieved into contiguous ranges of particle sizes. We also compared the 137Cs activities and stratification of several adjacent soils with known wind erosion and deposition histories. Finally, we tested 137Cs-based soil loss models with measured data from sites with documented histories. 137Cs activities and mean particle diameters of aeolian samples agreed well with the 137Cs activities and respective mean diameters of the sieved surface soil samples. Good agreement between model estimations and measured data indicated that 137Cs models developed to estimate soil redistribution by water were also applicable to soil redistribution by wind provided that the models contained an appropriate particle size correction parameter. [Copyright &y& Elsevier]

Abstract: Strong atmospheric winds may cause wind erosion and dust emissions on bare, dry, erodible fields. Since these dust emissions may exceed particulate matter limits established by the United States Environmental Protection Agency, information on dust generation and transport mechanics is needed to determine the particulate hazard of dust sources. Measurements of climatic variables and airborne sediment mass and concentration were made during three strong wind events on a bare, fine sandy loam field in west Texas. This study clearly shows that dust flux estimates were very sensitive to dust concentration measurement height. PM10 flux values estimated between heights of 2 and 5m were 2–5 times those estimated between heights of 5 and 10m. Tower placement in relation to the upwind unerodible boundary produced significant differences in dust flux that varied with storm intensity. During the most intense storm event, the PM10 flux between heights of 2 and 5m measured at the tower 200m from the unerodible boundary was almost 2.5 times as that measured at the tower 100m from the unerodible boundary. Vertical PM10 dust flux was closely related with horizontal sediment flux only when the winds came from the same direction during the entire duration of horizontal sediment flux measurements. [Copyright &y& Elsevier]