阴山北麓农牧交错区草地土壤风蚀测试

Test of Grassland Soil Erosion of Farming-pastoral Zone in Northern Foot of Yinshan Mountains

利用移动式风蚀风洞及相关配套设备对3种不同植被盖度的草地选择3种风速进行野外原位测试,获得了不同植被盖度草地的风速廓线和输沙量。结果表明,草地风速廓线总体上呈指数规律,且随地表高度的增加迅速增大;不同植被盖度草地在0～70 cm范围内输沙量与高度的关系以指数函数拟合效果好,输沙量主要集中在近地表30 cm以下;植被盖度55%的草地对在地表10 cm及以下的近地表风速阻挡效果与植被盖度80%的草地类似,其输沙量曲线与植被盖度80%的草地输沙量曲线很近,但距盖度30%的退化草地输沙量曲线较远。因此,植被盖度约50%是阴山北麓草地有效防风蚀的最低盖度。

The situ test in a grass field was conducted in three kinds of vegetation cover grass at three wind speeds, then the velocity profile and sediment discharge were obtained for different vegetation coverage of grassland by using mobile wind erosion wind tunnel device. The results showed that grass wind profile was exponent in generally and increased rapidly with the increase of height of surface elevation. There was a good fitting results for sediment discharge and height by using exponential function in the height of 0 - 70 cm for different vegetation coverage grasses, and the sediment discharge was mainly concentrated under the height of 30 cm of surface elevation. The barrier effect of near-surface wind speed was similar between 55% and 80% vegetation coverage of grassland under the height of 10 cm. The sediment discharge curve was very close between 55% and 80% grassland vegetation coverage, but the former was far from the sediment discharge curve of degraded grassland in 30% grassland vegetation coverage. Therefore, the minimum vegetation coverage was about 50% for preventing wind erosion effectively in the northern of Yinshan mountain.