Comparison of measured wind tunnel and SWEEP simulated soil losses

Wind erosion estimates from the Single-event Wind Erosion Evaluation Program (SWEEP) model of the Wind Erosion Prediction System (WEPS) were compared to wind tunnel experiments. The influences of wind speed and soil texture were investigated. From a previous study, soil losses were measured directly in a wind tunnel using three soil types (sandy loam, loamy sand, and sand), each under three free-stream wind speed conditions (10, 18, and 26 m s− 1). A different sand soil from another experiment was also tested under five wind speeds from 10 to 18 m s− 1 over intervals of 2 m s− 1 using a sediment trap and a flux profile estimating method. The comparison of measured and estimated agricultural soil losses under non-extreme winds (less than 18 m s− 1 in the wind tunnel) was good. The loamy sand comparison had an error less than 6% while the sandy loam soil had an error of about 35%. SWEEP underestimated the amount of erosion with the sand soil. However, because the estimating equations used in SWEEP to predict soil parameters for agricultural soils are not directly applicable to pure sand surfaces, this was expected. When conducting SWEEP simulations, it is recommended to use the actual aggregate size distribution (ASD) data, if available, rather than relying on SWEEPʹs ASD parameter values being estimated from other soil properties.