Yunnan Agricultural University Water Conservancy College
National Natural Science Foundation Project (32160304); Open fund project of "Science and Technology Innovation Team for Optimal Land Allocation and Ecological Renovation in Southwest Diversified Regions" of the Ministry of Natural Resources (YTD 2018 KF05); General Project of Yunnan Basic Research Plan (202201 at 070272); Yunnan Province Agricultural Basic Research Joint Special General Project (202301BD070001-033；; 202301BD070001-103）； Youth Project (2019FD 094), a planned project of Yunnan Science and Technology Department; Major Project of Water Conservancy Science and Technology in Yunnan Province (2023BG204001)
The characteristics and interaction between plant roots and soil are the key to ecological slope protection. In this paper, the concept and connotation of root-soil complex, the mechanical effect of root-soil complex and the principle, advantages and disadvantages and application scope of mechanical model are summarized and analyzed by literature analysis and comparative analysis. The results show that the root-soil complex is a complex and stable whole based on the coupling relationship of mechanical effects between roots and soil, and the roots are intertwined in the soil, which plays a similar role in strengthening fibers. The mechanical relationship between root and soil is essentially a result of the interaction of soil force, hydraulic force and composite mechanical characteristics of root-soil complex. The soil force characteristics focus on the influence of plant root characteristics on soil, the hydraulic characteristics focus on the influence of water movement and water holding capacity in soil on soil structure, soil physical and chemical properties and root characteristics, and the composite characteristics focus on the direct influence of soil characteristics on plant root characteristics and structure, so that the mechanical relationship between root and soil is in a dynamic balance through the interaction of the three. The research on the composite mechanical model of root-soil complex is slightly less than that of soil force and hydraulic model. The soil mechanical model focuses on the relationship between roots and soil characteristics through experiments and formulas to quantify the reinforcement of roots, while the hydraulic characteristic model quantifies the hydraulic characteristic parameters through numerical simulation, both of which measure the soil consolidation effect according to the comparison between parameters. However, composite mechanics involves both soil and hydraulic characteristics, so it should be the key research direction in the future. In the future, the effects of freeze-thaw cycle, dry-wet alternation and dry-hot cycle on root-soil interaction in different regions, the shear strength of multi-type plant mixtures, the influence mechanism of chemical and microbial effects on soil-water characteristics and the construction of composite models need to be further studied. This paper can provide important theoretical value and engineering reference for vegetation restoration, soil and water conservation and sustainable development in ecologically fragile areas.