塔里木河下游不同覆盖度灌木防风固沙功能野外观测研究

Field Investigation on Function of Reducing Wind and Stabilizing Sand under Different Vegetation Cover in Lower Reaches of Tarim River

对塔里木河下游50%、25%、10%三种覆盖度灌木降低风速观测结果表明：50%覆盖度灌木降低风速最明显,防风效能为49.21%;25%的覆盖度灌木降低风速较明显,防风效能为24.44%;10%的覆盖度灌木对风速降低有一定作用,防风效能为9.15%。在7.7m·s^-1风速下,植被覆盖度为10%、25%的沙地输沙率分别是无植被覆盖沙地的62.44%和8.37%;在10m·s^-1风速下,植被覆盖度50%的沙地仅有轻微的风蚀。根据塔里木河下游不同覆盖度植被与降低风速之间的定量关系,得出不同风速条件下的有效植被覆盖率,在研究区常见10～15m·s^-1风速条件下,要达到有效阻沙效果,植被覆盖率应在50%以上。

Investigation into the effect on reducing wind under three kinds of different vegetation coverage（50%,25%,10%） in lower reaches of the Tarim River shows that their effect are respectively 49.21%,24.44% and 9.15%.Under wind velocity of 7.7 m·s^-1,the sand transporting rate over vegetation coverage of 10% and 25% is respectively 64.44% and 8.37% of that over non-vegetation cover;Under wind velocity of 10 m·s^-1,only slight wind erosion occurred on the land with 50% vegetation coverage.Quantitatively analysis on the relationship between different vegetation coverage and reduction of wind velocity shows the effective vegetation degree of coverage.Under the common wind velocity（10～15 m·s^-1）,the effective vegetation coverage should be above 50% for preventing wind erosion.