寒旱环境黄土区灌木根系护坡力学效应研究

A study of the mechanical effects of shrub roots for slope protection in frigid and arid-semiarid loess area

文章采用原位拉拔试验，测定了生长2年的灌木柠条锦鸡儿、四翅滨藜、霸王、白刺的抗拔力，研究了根系的分布特征，并分析了上述植物的护坡效果。试验结果表明：4种灌木的根系分布类型均以主直根型为主，根系发达，侧根主要集中在地表以下20—80cm的土层中；4种灌木的原位抗拔力依次为四翅滨藜〉柠条锦鸡儿〉白刺〉霸王，抗拔力与根径符合幂函数关系，与根系数量符合线性关系，与株高符合指数函数关系；随着生物指标的增加，四翅滨藜和柠条锦鸡儿的抗拔力递增幅度明显高于霸王和白刺；从根系分布特征和力学效应考虑，四翅滨藜和柠条锦鸡儿可作为寒冷干旱半干旱黄土地区的优势护坡灌木种。

The pull-resistance was determined by the in situ pull-out test for four two-year-old brush species, including Caragana korshinskii, Antiplex canescens, Zygophyllum xanthoxylon, Nitraria tangutorum. The distribution characteristics of root system were studied and the slope protection effects of these brushes were analyzed. The results indicate that the main distribution type of root is straight root system, and the main branch roots distribute at a depth of 20 - 80cm below land surface. The order of the four brush species pull-resistance is Caragana korshinskii 〉 Antiplex cartescens 〉 Nitraria tangutorum 〉 Zygophyllum xanthoxylon. There exists a power relation between the pull-resistance and the diameter, a linear relation between the pull-resistance and the branch root quantity, and a exponential relation between the pull-resistance and the plant height. Pull-resistance increases with increasing biological indexes, and the increasing extent of Caragana korshinskii and Antiplex canescens are bigger than Nitraria tangutorum and Zygophyllum xanthoxylon. Considering the distribution characteristics of root system and the mechanical effects, Atriplex canescens and Caragana korshinskii can be taken as the good shrubs for slope protection in frigid and arid-semiarid loess area.