典型草原抗风蚀能力的实验研究

Experimental Research on the Anti-Wind Erosion of Typical Grasslands

为了了解人为干扰对典型草原抗风蚀能力的影响,采用风洞实验的方法对不同干扰条件下典型草原原状土的抗风蚀能力进行了研究.不同时间禁牧草原的风洞实验结果表明,禁牧典型草原的风蚀量和风蚀率都明显低于自由放牧草原,而且,在相同风速下,禁牧时间越长,侵蚀率及侵蚀量越小;草原开垦后,土壤的侵蚀率和侵蚀量远远高于典型草原,而且风速越大,相差越大;草原土壤侵蚀率随风速的增加而增加,但受草原土壤可侵蚀量的限制.另外,人工模拟干扰实验表明,典型草原土壤的侵蚀率与干扰程度呈直线相关关系.结果说明:放牧及耕作会使典型草原的抗风蚀能力明显降低,而禁牧可以有效提高其抗风蚀能力.在典型草原区,实行禁牧是遏制草原退化的有效措施.

Wind erosion is one of the most important factors influencing the stability and functions of typical grassland ecosystem and one of the main reasons causing grassland degradation. In order to understand the effects of the human disturbances to the ability of anti-wind erosion of the typical grasslands, a wind tunnel experiment was made and the wind erosion rates （WER） and wind erosion amount （WEA） were selected to illustrate the effects. From the experiment, it can be found that banned-grazing reduced the WEA and the WER markedly. At the same wind speed, the longer the banned-grazing period, the less the WEA and the WER; the WEA and the WER in the grassland cultivation are more than those of the natural grasslands and the differences increase with wind speed. There exists a linear relationship between WER and the disturbance intensity. The results show that grazing and cultivation can weaken the ability of anti-wind erosion of typical grassland ecosystem, and banned-grazing can strengthen the ability. Therefore, in typical grassland areas, taking the active banned-grazing measures is the most effective approach to stop the degradation and trigger the rehabilitation of typical grassland ecosystem.