Abstract:In order to provide a biomechanical reference for the selection of excellent tree species for soil fixation and erosion resistance,and to reveal the mechanical characteristics of plant roots for continuous soil fixation and erosion resistance,three typical native plant roots of 3-year-old Caragana korshinskii, Hippophae rhamnoides and Medicago sativa in the complex erosion area of wind and water in the central and Western Inner Mongolia were taken as the research objects. Under the same site conditions,using the self-made portable root radial and axial mechanical properties test bench and HG100 digital display push-pull meter, 70% ultimate bending force of single root was damaged in the test diameter range of 0.5~4 mm. After 3 months of self-healing, the changes of anti-fracture forces and anti-fracture strength of three kinds of plant roots after damaged callus were studied, and the differences among different plant species were compared. The results showed that the average comparison of anti-fracture strength of three kinds of plants after restoration were Caragana korshinskii (15.504 Mpa)>Hippophae rhamnodes (12.342 Mpa)>Medicago sativa (6.584 Mpa), indicating that the bending resistance of Caragana korshinskii was better than that of Hippophae rhamnodes and Medicago sativa, and Hippophae rhamnodes was better than Medicago sativa. However, in numerical value, there was no significant difference in single root anti-fracture strength between Medicago sativa parallel control group and after callus. For the average anti-fracture forces, Caragana korshinskii, Hippophae rhamnodes and Medicago sativa decreased by 64%, 28% and 27% respectively. For the average anti-fracture strength, Caragana korshinskii, Hippophae rhamnodes and Medicago sativa decreased by 40%, 22% and 12% respectively. These results showed that the biological characteristics of different plant species were different, and the recovery ability of erosion resistance was different after damaged callus.