关键词: 草本植物, 根-土复合体, 力学特性, 影响因素, 石漠化区, 滇中高原

Abstract: In order to elucidate the soil reinforcement mechanisms of herbaceous plant roots in the rocky desertification area of the central Yunnan Plateau and to provide a theoretical basis for the scientific configuration of ecological restoration and vegetation slope protection engineering in such regions, this study took the typical herbaceous plants Chromolaena odorata (L.) R. M. King & H. Rob., Nephrolepis cordifolia (L.) C. Presl, and Blumea balsamifera (L.) DC. in this area as research objects, and systematically investigated the effects of root species, root number, and root distribution pattern on the mechanical properties of root-soil composites through single-root tensile tests and direct shear tests combined with an L₉(3³) orthogonal design. The results showed that the proportions of roots with a root diameter of 0.5-1.5 mm for Blumea balsamifera, Chromolaena odorata, and Nephrolepis cordifolia were 47.21%, 29.27%, and 65.74%, respectively. The root tensile strength ranked in the order of Nephrolepis cordifolia (28.10 MPa) >Chromolaena odorata (22.92 MPa) >Blumea balsamifera (18.81 MPa). The relationship between root diameter and root tensile strength followed a decreasing power function, with R² values ranging from 0.459 3 to 0.653 0, whereas the relationship between root diameter and maximum single-root tensile force followed an increasing power function, with R² values ranging from 0.877 7 to 0.962 2. Compared with bare soil, roots enhanced the shear strength of the root-soil composite, and this reinforcing effect was mainly manifested as an increase in cohesion, whereas changes in the internal friction angle contributed only marginally. Analysis of variance indicated that the cohesion of the root-soil composite was significantly correlated with both root number and root distribution pattern, and the internal friction angle was significantly correlated with root number, whereas root species had no significant effect on either cohesion or the internal friction angle. The optimal combination for the root-soil composite was A₂B₂C₃, i.e., using Nephrolepis cordifolia with six roots arranged in a vertical (90°)-inclined (45°) cross-distribution pattern, and the study confirmed that optimizing root number and root distribution pattern was key to improving the shear performance of the root-soil composite.

Key words: herbaceous plants, root-soil composite, mechanical properties, influencing factors, rocky desertification area, central Yunnan Plateau