沙柳沙障的防风固沙效益研究

Effect of Salix psammophila Checkerboard on Reducing Wind and Stabilizing Sand

研究测定了1m×1m,1m×2m,2m×2m,2m×3m,2m×4m,2m×5m,3m×3m,3m×4m,4m×4m,4m×5m,3m×6m等11种规格沙柳沙障内的风沙活动过程和分布规律。结果说明,不同规格沙障内输沙率随着风速的变化其变化趋势不同,小规格沙障内输沙率与风速呈对数曲线关系,大规格沙障内输沙率与风速之间呈指数曲线关系。沙柳沙障中近地表0～4cm范围内,风沙流中的相对含沙量沙丘下部明显大于沙丘中部和上部,说明沙障导致了近地表风沙流结构发生变化。面积等于或小于1m2的沙障可以完全控制地表风蚀,当沙障面积增加到一定程度后,风蚀深度增加很快。不同规格沙障的防护效益,在大风条件下,小规格沙障的成本效益高于大规格的沙障;在小风情况下,大规格沙障的成本效益大于小规格沙障。

In this study, the material used to build straw checkerboard is branch of \%Salix psammophila,\% one native shrub in desert area. The sizes of checkerboard are 1 m×1 m,1 m×2 m, 2 m×2 m,2 m×3 m,2 m×4 m, 2 m×5 m,3 m×3 m, 3 m×4 m, 4 m×4 m, 4 m×5 m, 3 m×6 m. Results show that different sized checkerboards have different effects to reduce the sand flux intensity. Sand flux intensity varies logarithmically with wind velocity in the small sized checkerboard. Meanwhile, sand flux intensity varies exponentially with wind velocity in the large sized checkerboard. At the foot of dune with checkerboard on it, the sand flux intensity in 0～4 cm surface layer is significantly larger than that at the slope and the top of dune. The checkerboards with a size area equal to or less than 1 m^(2) can completely control wind erosion. If the size of checkerboard increases to over certain area, wind erosion will increase fast considerably. When considered both the effect of checkerboard on wind erosion control and its cost, small sized checkerboard has good effect under strong wind condition; the larger sized checkerboard is better under relatively weak condition.