天然降雨条件下裸露砒砂岩区人工植被的减流减沙效应

裸露砒砂岩区是黄土高原上侵蚀最为剧烈的地区之一,研究裸露砒砂岩区天然降雨下人工植被的减流减沙效应,对于提升砒砂岩区水土流失治理成效与质量有重要意义。以裸露砒砂岩区鲍家沟小流域的典型人工植被为研究对象,运用系统聚类和线性回归相结合的方法,划分裸露砒砂岩区降雨类型,研究不同降雨类型下坡面产流产沙的特征,分析不同人工植被的减流减沙效应。结果表明:(1)裸露砒砂岩的自然降雨可以分为长历时暴雨、长历时的中到大雨、短历时暴雨以及短历时的小到中雨4种类型。(2)天然降雨的降雨量(P)、最大30 min雨强(I₃₀)和最大10 min雨强(I₁₀)与各植被类型坡面的产流量、产沙量间呈y=ax₁+bx₂+cx₃+d的多元线性关系。(3)各植被类型的减流能力依次为沙棘林>油松林>山杏林>柠条林>草地; 减沙能力依次为沙棘林>山杏林>油松林>柠条林>草地。营造人工植被可以有效防治裸露砒砂岩区坡面的水土流失问题,现有的人工植被类型中以沙棘林的抗蚀能力最强。

Effects of Artificial Vegetation on Runoff and Sediment Reduction by in Exposed Feldspathic Sandstone Region Under Natural Rainfall

The exposed feldspathic sandstone region is one of the areas susceptible to most severe soil and water losses in the Loess Plateau.Studying the effects of artificial vegetation on runoff and sediment reduction in exposed feldspathic sandstone region under natural rainfall has great significance to improve the effectiveness and quality of soil erosion control.In this research,through hierarchical clustering method and linear regression method,we divided the types of rainfall and studied their effects on soil erosion,and also analyzed the erodibility under different typies of artificial vegetation in Baojiagou watershed of Feldspathic sandstone region.The results showed that:(1)the natural rainfall types in exposed feldspathic sandstone region could be conceptually divided into four categories:long-duration heavy rain,long-duration moderate to heavy rain,short-duration heavy rain,short-duration light to moderate rain;(2)multiple linear function relation could describe the relation between P,I₃₀,I₁₀ of rainfall and runoff yield,sediment yield under differernt artificial vegetation types(y=ax₁+bx₂+cx₃+d);(3)the runoff reduction ability of different vegetation types followed the order:Hippophae rhamnoides>Pinus tabuliformis>Prunus armeniaca>Caragana korshinskii>grass land;(3)it was also found that sediment reduction capacity decreased in the order:Hippophae rhamnoides>Prunus armeniaca>Pinus tabuliformis>Caragana korshinskii>grass land.Construction of artificial vegetation can effectively prevent and control soil and water loss on the slope of exposed feldspathic sandstone area.Among the existing artificial vegetation types,Hippophae rhamnoides forest has the strongest ability to control erosion.