沙棘“柔性坝”对土壤水分调控作用的试验研究

沙棘植物“柔性坝”拦沙淤积效果明显，为了探求沙棘“柔性坝”对土壤水分的调控作用，在内蒙古准格尔旗西召沟东一支沟小流域内对5座沙棘“柔性坝”开展了野外试验研究，同时在东一支沟左岸一未种植沙棘“柔性坝”的小支沟进行了对比试验。沿沟道及“柔性坝”坝体纵向设置若干断面，每个断面设2～3个采样点，每个采样点在1 m深度范围内分9层采集土样测定土壤含水率。试验结果表明：降雨后，沙棘“柔性坝”坝体土壤水分的垂向分布呈现降低型(土壤含水率随土层深度的增加而降低)；而对比沟各断面的土壤含水率的垂向分布则为增长型或波动型。这表明沙棘“柔性坝”有利于雨水下渗和增加土壤含水率，进而起到保水固土和促进植被生长的作用。从“柔性坝”坝体中部至上游淤积体，平均土壤含水率呈现纵向递增趋势；并基于达西定律探讨了断面平均土壤含水率与纵向距离之间的关系。

Experimental research on the soil moisture regulation of seabuckthorn plant flexible dams

Seabuckthorn plant fleixble dam plays an important role in controlling soil sediment. In order to explore the soil moisture regulation of seabuckthorn dams, field experiments were carried out for five seabuckthorn dams and a small valley without seabuckthorn plant flelxible dams in Xizhao watershed, Inner Mongolia. Along the seabuckthorn dams and the small valley, several sections were set, two to three sample points for each section were selected. Soil samples were vertically selected from nine layers within 1 m depth to measure soil moisture content respectively. Results show that after a rainfall event, in the seabuckthorn dam body, the vertical distribution of soil moisture content exhibits decreasing type(soil moisture content decreases with the increase of soil depth). While in the small valley without flelxible dams, increasing or fluctuating types are observed. The seabuckthorn dam plays a positive role in the enhancement of rainfall infiltration, the maintenance of soil moisture, water and soil conservation and vegetation growth. From the midst of flelxible dam to the upstream silt layer, there exists a trend of longitudinal increase of average soil moisture content. Relationships between average soil moisture content and vertical distance were discussed based on the Darcy's law.