摘要
通过对毛乌素沙地不同下垫面上风速、地表粗糙度、临界起沙风速、风沙流结构的观测,发现植被覆盖可以有效防止地表风蚀。植被盖度为40%的固定沙地近地表0.2 m高度平均风速比流动沙地降低43%,侵蚀风的持续时数降低85%,临界起沙风速提高70%,地表粗糙度提高180倍;当风沙流速度相同时,20%覆盖度的半固定沙地较流动沙地可平均降低输沙62.33%;而植被盖度为40%的固定沙地较流动沙地可平均降低输沙93.07%。实验证明,单株植物同样可以降低风速。疏透结构和透风结构的单株沙蒿分别可以使植株后0.5 m高度的风速较植株前方平沙地同高度的风速下降59.4%和19.8%。
Through field investigation on wind speed, aerodynamic roughness, rate of sand transportation, and structure of wind-sand flow on different underlying surfaces, we found that vegetation cover can effectively prevent soil erosion by wind. In comparison of the fixed sandy land of 40% vegetation coverage with the drifting sand dune without coverage, the average wind speed at the height of 0.2 m was reduced by 43%, the successive time of threshold wind velocity for soil erosion was reduced by 85%, the threshold wind velocity for soil erosion was increased by 70%, and aerodynamic roughness was increased as much as 180 times. Compared with the drifting sand dune, when the speed of wind sand flow is similar, the rate of sand trans- portation on the semi fixed sandy land was reduced by 62.33%, while fixed sandy land, by 93.07%. The re sults indicate that a single plant can also reduce wind speed. Two single Arternisia ordosica can reduce wind speed at the height of 0.5 m by 59.4% and 19.8%, respectively.
出处
《水土保持通报》
CSCD
北大核心
2008年第5期55-59,共5页
Bulletin of Soil and Water Conservation
基金
国家科技支撑课题(2006BAD26B03
2006B0702)
关键词
土壤风蚀
植被盖度
地表粗糙度
输沙率
风沙流结构
soil erosion by wind
vegetation coverage
aerodynamic roughness
rate of sand transportation
structure of wind-sand flow
