Study On The Differences Of Plants Foliage-root Soil-reinforcement And Anti-erosion

This paper toke five kinds of common soil and water conservation shurbs of study area that Caragana microphylla Lam., Salix psammophila C.wang et Ch.Y.Yang, Sabina vulgaris Ant., Artemisia sphaerocephala Krasch. and Hippophae rhamnides Linn, which were at the age of 3-4 (mainly 4) as the research object. In this paper, the root-soil composite shear property under saturated moisturecontent, dominant mechanical factor and differences of soil-reinforcement by roots of 5 kinds of plants and differences of foliage-root soil-reinforcement and anti-erosion of 4 kinds of plants beside Sabina vulgaris Ant. were researched. The results showed that:(1) During the period of spring soil drought and summer soil saturated moisturecontent, ten indicators (root-soil composite cohesive, root-soil composite equivalent friction angle, root-soil interface sheer strength, accumulation surface area, interface friction coefficient, represented root elasticity modulus, represented root constitutive properties, taproots tensile strength, lateral roots branch tensile strength, length of accumulative root) of the five species were analyzed by principal component analysis (PCA). From the results of PCA, the dominant factors are in the sequence of tensile mechanical property, root-soil surface friction property, and root-soil composite shear property.(2) Based on the outcome of PCA, the soil-reinforce performance of the five species are evaluated. The evaluation result showed the index of soil-reinforcement by roots in spring soil drought were in the sequence of Caragana microphylla Lam. (0.834)> Salix psammophila C.wang et Ch.Y.Yang (0.303)> Artemisia sphaerocephala Krasch. (-0.066)> Sabina vulgaris Ant. (-0.206)> Hippophae rhamnides Linn. (-0.864), and in the summer soil saturated moisturecontent were in the sequence of Caragana microphylla Lam. (0.876)> Sabina vulgaris Ant. (0.218)> Salix psammophila C.wang et Ch.Y.Yang (0.065)> Artemisia sphaerocephala Krasch. (-0.404)> Hippophae rhamnides Linn. (-0.755). Establishing an ideal model of soil-reinforcement by root, and evaluate the optimal value of ten indicators. The results showed that the index of soil-reinforcement by root of the ideal model in spring soil drought and summer soil saturated moisturecontent was 1.415 and 1.485.(3) On the basis of ten soil-reinforcement indicators, other three indicators (single shrub reduce wind velocity ration, shelterbelt reduce wind velocity ration, community reduce wind velocity ration) which reflected the windbreak characteristics were added to evaluate the differences of foliage-root soil-reinforcement and anti-erosion during the period of spring gale and summer soil saturated moisturecontent, respectively. The results showed the foliage-root anti-erosion index was in the sequence of Salix psammophila C.wang et Ch.Y.Yang (0.841)> Caragana microphylla Lam. (0.454)> Artemisia sphaerocephala Krasch. (-0.466)> Hippophae rhamnides Linn. (-0.829) in spring gale, and Caragana microphylla Lam. (0.841)> Salix psammophila C.wang et Ch.Y.Yang (0.474)> Artemisia sphaerocephala Krasch. (-0.470)> Hippophae rhamnides Linn. (-0.844) in summer soil saturated moisturecontent. The index of foliage-root soil-reinforcement and anti-erosion of the ideal model in spring gale and summer soil saturated moisturecontent was 1.393 and 1.442.(4) The root-soil composite shear strength of five plants shows extremely significant difference under saturated moisturecontent circumstance, and the shear strength under four kinds of vertical load were greater than plain soil. In the main distribution layer (root depth of 1.5 m), five kinds of root-soil composite shear strength followed by Salix psammophila C.wang et Ch.Y.Yang> Sabina vulgaris Ant.> Hippophae rhamnides Linn.> Caragana microphylla Lam.> Artemisia sphaerocephala Krasch. The root-soil composite cohesive of five plants are more intensive than plain siol, and the growth rate was between 14.76%-21.50%. The root-soil composite equivalent friction angle has no obvious change, and the growth rate was between -4.90%-5.16%.