[目的] 研究循环荷载对3种典型灌木根系抗拉力学特性的影响，明确疲劳作用后灌木根系固土效能的变化，为半干旱矿区生态修复和侵蚀防控过程中的植物种选择提供科学依据。 [方法] 以北沙柳、小叶锦鸡儿和沙棘根系为研究对象，利用TY8000伺服控制材料试验机对2～4 mm根径范围内的直根及侧根分支处施加轻度和重度循环荷载，分析疲劳前后根系抗拉力和抗拉强度的变化。 [结果] ①3种灌木根生物量、累计根长、根体积和根表面积种间差异显著，均表现为：北沙柳＞小叶锦鸡儿＞沙棘，且根生物量和根体积均主要分布于0-10 cm的表层土体，所占比例平均为38.5%和35.3%，累计根长和根表面积均主要分布于10-20 cm的浅层土体，所占比例平均为30.1%和29.8%。 ②3种灌木直根在疲劳前后抗拉力均与根径呈幂函数正相关，抗拉强度均与根径呈幂函数负相关，且抗拉力和抗拉强度均表现为：小叶锦鸡儿＞北沙柳＞沙棘，根系疲劳可显著提升直根抗拉性能。 ③3种灌木侧根分支处在疲劳前后抗拉力与抗拉强度随根径的变化与直根相似，疲劳前小叶锦鸡儿抗拉力最大，北沙柳次之，沙棘最低，但疲劳后却表现为：沙柳＞小叶锦鸡儿＞沙棘，根系疲劳可显著提升北沙柳和沙棘侧根分支处的抗拉力学性能，却会降低小叶锦鸡儿抗拉能力。 [结论] 在风蚀环境中，北沙柳根系在侵蚀过程中能始终保持良好的抗拉性能，可发挥稳定的固土抗蚀效能，应作为半干旱矿区植被重建的优选植物种。
[Objective] The effects of cyclic load on root tensile resistance characteristics of three typical shrubs, and the change of soil reinforcement efficiency of shrub roots after fatigue were determined in order to provide a scientific basis for plant selection in the process of ecological restoration and erosion prevention and control in semi-arid mining areas. [Methods] The roots of Salix psammophila, Caragana microphylla, and Hippophae rhamnoides were taken as the research objects. The TY8000 servo-controlled material testing machine was used to apply mild and severe cyclic loads on the taproots and lateral root branches within the root diameter range of 2~4 mm, and changes in root tensile force and tensile strength before and after fatigue were analyzed. [Results] ① There were significant differences in root biomass, cumulative root length, root volume, and root surface area among the three shrubs that followed the order of S. psammophila ＞ C. microphylla ＞ H. rhamnoides. The root biomass and root volume were mostly concentrated in the 0-10 cm surface soil, with proportions of 38.5% and 35.3%, respectively. The cumulative root length and root surface area were mostly concentrated in the 10-20 cm shallow soil, with proportions of 30.1% and 29.8%, respectively. ② The tensile force of the taproots of the three shrubs before and after fatigue was positively correlated with root diameter by a power function relationship, and a negative power function relationship between tensile strength and root diameter was observed. Both tensile force and tensile strength of the three shrubs followed the order of S. psammophila ＞ C. microphylla ＞ H. rhamnoides. Root fatigue significantly improved the tensile properties of the taproot. ③ Before and after fatigue, the tensile force and tensile strength of the lateral root branches of the three shrubs were similar to that of the taproot. Before fatigue, the tensile force of C. microphylla was the highest, followed by S. psammophila, and H. rhamnoides was the lowest. However, after fatigue, the tensile force followed the order of S. psammophila ＞ C. microphylla ＞ H. rhamnoides. Root fatigue can significantly improve the tensile properties of lateral root branches of S. psammophila and H. rhamnoides, but can decrease the tensile properties of C. microphylla. [Conclusion] In a wind erosion environment, the root system of S. psammophila can always maintain good tensile performance during the erosion process, and can exert a stabilizing soil reinforcement effect, and therefore, this species should be considered as the better choice for vegetation reconstruction in semi-arid mining areas.