摘要
风沙流的危害是多方面的,不仅破坏地表结构,削弱土壤的抗风蚀性,而且影响到植物的生长,损坏工农业设施。通过在便携式风洞内模拟挟沙气流,研究了风沙流对土壤风蚀的影响。结果表明,风沙流可不同程度地降低土壤地表结构的临界起沙风速,使土壤变得更易风蚀。风沙流因子对于土壤风蚀的影响,在不同的风速段具有不同的特征。在较低风速段,风蚀量随风速增加缓慢,当风速进一步加大,风蚀量则急剧增加,其差异最多可达4倍之多;而当风速增大到10m/s以上时,风蚀量反而有所减小,说明随着风速的加大,更多的沙粒具有了更大的动能,其运行高度增加,对土壤表面的影响作用减小,但风蚀量仍大于净风时的风蚀量。由于风沙流的磨蚀和撞击作用,削弱了土壤的抗风蚀性,使土壤变得更易风蚀。因此,采取综合措施对风沙源进行彻底治理,是控制沙漠化发展,改善生态环境的关键。
The damage of wind-sand flow is multiaspect, not only its destruction to soil surface texture and weakening to anti-erodibility of soil, but also affection on vegetable normal growth and mutilating to industrial and agricultural facilities. In this paper, influence of wind-sand flow on soil wind erosion was discussed using portable wind tunnel to simulate natural wind. The results indicated that critical threshold wind velocity of soil surface can be reduced when wind-sand flow appears, and this makes soil more easily to be eroded. The influence on wind erosion had different characteristics under variant wind velocity scope. Wind erosion rate increases slightly in a lower scope of wind speed, while a rapid increase presents in a higher period of wind speed which accompanies a contrast of more than 5 times compared with clean wind, when wind velocity exceeds 10m/s, wind erosion rate decreases dramatically. This phenomenon showed that more sand saltates at a higher height when it obtains more kinetic energy, which weakens the anti-erodibility of soil, although wind erosion rate is greater than that of it is under clean wind condition. Because of sandy mutual impacting and abrading, it attenuates the anti-erodibility of soil making ground surface to be eroded easily, so integrated ways should be take into account to control the source of wind-sand flow. This is the key to inhibit expand of desertification and to improve ecological environment.
出处
《水土保持学报》
CSCD
北大核心
2005年第3期58-61,共4页
Journal of Soil and Water Conservation
基金
国家自然科学基金资助项目(40471004)
中国科学院野外台站基金资助项目(1731690200015)
关键词
风沙流
土壤风蚀
便携式风洞
wind-sand flow
wind erosion
portable tunnel
