Difference in wind erosion characteristics between loamy and sandy farmlands and the implications for soil dust emission potential

摘要

Dust emission depends directly and indirectly on soil particle distribution, but little information is available that examines dust emission potential and its relationship with wind erosion for different soils. This study aimed to elucidate the difference in wind erosion characteristics between loamy farmland (LF) and sandy farmland (SF) and discuss the influence of this difference on dust emission potential. Field observations were conducted during 2012-2016 in Bashang district, North China. With increasing friction wind speed, the horizontal mass flux increased exponentially in LF but obeyed the power function in SF. The horizontal mass flux was higher in SF than in LF, but the gap narrowed from 766 times at friction wind speed of 0.3 m s-1 to 50 times at 0.6 m s-1. The dry aggregate size distribution of sediment in LF was finer than in SF. Fine particle content (diameter 0.05 mm) in windblown sediment was much higher in LF (31.39%) than in SF (5.92%), which was influenced by parent soils. With height increasing, the mass percentage of sediment decreased more rapidly in SF than in LF, with 86% and 66% of sediment clustering at height 0-20 cm, respectively. Because the horizontal mass flux and dust content in sediment both increased more quickly in LF than in SF with increasing friction wind speed, the dust emission potential was larger in LF than in SF under strong winds. The adverse effect of dust emission in loamy soils on atmospheric pollution should receive more attention in strong wind erosion events.