A Field test of the Wind Erosion Prediction System

Field data need to be collected to test wind erosion models under a broad range of climate, soil, and management conditions. The objective of this study was to test the USDAARS Wind Erosion Prediction System (WEPS) for a field with winter wheat plants in a modest amount of flat residue. A 600 m by 415 m field was selected near Burlington, CO, USA. Big Spring Number Eight (BSNE) samplers were used to measure wind blown sediment flux and automated devices (Sensits) for continuous detection of saltation. A weather station recorded relevant meteorological data. Detailed measurements of the field surface were taken on three dates. The experiment was conducted from 25 November, 2000 through 12 April, 2001. One dust storm occurred during this experimental period, with a net field sediment loss of 0.06 kg/m. Spatial variability of sediment discharge was high and could be explained by spatial differences in field conditions. WEPS overestimated the protective power of small wheat plants. It needs a provision to account for standing biomass that is not uniformly spaced, such as wheat plants in the field. Wind erosion (and WEPS) is very sensitive to soil surface water content, which is difficult to measure. Albedo is a good indicator of soil wetness right at the soil surface, but additional research is needed to use albedo for quantifying soil surface water content.