毛乌素沙地不同植被条件下的土壤风蚀效果

Soil erosion feature under different vegetation in Mu Us Sandland with

在对毛乌素沙地植被类型和状况调查的基础上,选择沙柳、小叶锦鸡儿+杂类草、沙蒿+杂类草、芨芨草等四种主要类型的植被为研究对象,通过标杆法测定不同植被下地表的土壤侵蚀或堆积状况,从而探讨不同类型植被的防风固沙效果,为毛乌素沙地利用植被防风固沙提供依据。结果显示,在30%盖度以下时,各种类型植被下均有比较严重的水土流失现象。在植被盖度达到45%以上后,水土流失现象基本消失。各类植被的水土流失盖度临界值分别为:沙柳38%、小叶锦鸡儿+杂类草37%、沙蒿+杂类草34%、芨芨草32%。在相同的植被盖度下,不同类型的植被显示了不同的滞留土壤能力。综合地理条件和水分情况考虑,沙蒿+杂类草植被和小叶锦鸡儿+杂类草植被更适合于在毛乌素沙地作为防风固沙植被推广。利用植被防风固沙,不仅要达到临界盖度,而且要灌草结合才能达到更好的效果。

Based on the vegetation types and status, efforts were made to investigate the soil erosion features under different vegetation in Mu Us Sandland. Four different vegetation forms of Salix cheilophila, Caragana microphlla ＋ herbosa. Artemisia sphaerocephala＋herbosa, Achnatherum splendens were selected as testing transects for soil erosion measurement. Soil loss or accumulation under the measureing pole was used as a judgment for soil erosion degree. The results showed that severe soil erosion occurred under a vegetation coverage below 30%, while no obvious soil erosion occurred under a vegetation coverage above 45 %. Threshold coverages for the four forms were 47 % for Form Salix cheilophila, 44% for Form Caragana microphlla ＋ herhosa. 42~ for Form Artemisia sphaerocephala ＋herbosa,and 40% for Form Aehnatherum splendens. Under the same coverage, different vegetation showed varied soil sustaining capacity. Form Caragana microphlla ＋ herbosa and Form Artemisia sphaerocephala ＋herbosa were considered suitable vegetation for soil erosion control in the Mu Us sandland region.