Estimating the saltation and suspension components from field wind erosion

Improving wind erosion prediction and control requires correct estimates of the suspended dust (ss) and saltation (sn) components from field erosion events. The objectives of this study were to (a) develop an improved methodology (HPS) to estimate the fractions of sn and ss in the sediment discharge, and (b) compare HPS predictions to those of LM (Leys and McTainsh, 1996) and CN (Chepil and Woodruff, 1978; Nickling, 1978) that included or FS (Fryrear and Saleh, 1993) that excluded size measurements of the trapped sediment. Sediment flux profiles from nine field studies in four states were used in the data analyses. The log form of the ss flux profile developed in the LM method for dispersed particles had poor data fit to profiles of aggregated particles. The FS, HPS, and CN methods predicted significantly different ratios of ss discharge to total discharge in the order FS < HPS < CN. The widely-used power form of the ss flux profile in the CN method provided a good data fit above 0.1 m, but over estimated ss flux near the surface. The FS method over estimated sn and under estimated ss components. The HPS method obtained good fits to the data, even when profile gradients were large. Thus, using the sieved sediment catch from passive sediment catchers coupled with HPS analysis methodology offered significant improvements in the accuracy of estimates of sn and ss discharge. On short fields, the fraction of ss discharge was related to soil texture.