Effects of slope nature on the root morphology and pull-out force of Deutzia scabra and Lespedeza bicolor

In this study, Deutzia scabra and Lespedeza bicolor, the dominant local shrubs in the Songshan Area, were selected as the research objects. The root morphology and pull-out force of the two plants in rocky and soil slopes were studied by root digging, in situ pull-out force, and Win-RHIZO root scanning methods in order to provide theoretical assistance for the study of suitable growth strategies for plant roots as well as slope protection under different natural slope conditions. The results showed that: 1) In rocky slopes, the root length density, root weight density, and specific root length of D. scabra were significantly larger than those of soil slopes (P < 0.05). In rocky slopes, the root length density and specific root length of L. bicolor were significantly less than those of the soil slopes (P < 0.05), while the root weight density was not significantly difference between the two environments ( P > 0.05). 2) A significant difference in the number of basal roots of D. scabra under two slope conditions was present (P < 0.05), and there was no basal root in soil slope. In rocky slopes, the diameter of the basal roots of L. bicolor was significantly larger than that of soil slopes (P < 0.05), while the number of basal roots were no significant difference ( P > 0.05).3) Compared with what was present aboveground, slope nature had a greater influence on root biomass. In rocky slopes, the root biomass and root-shoot ratio of two species of plants were significantly greater than those of plants from the soil slopes ( P < 0.05). 4) The slope nature had an obvious effect on the maximum pull-out force of the plant roots, and D. scabra and L. bicolor showed a strong ability for slope protection on rocky and soil slopes. In short, slope nature has obvious effects on root morphological and mechanical properties of D. scabra and L. bicolor. The root system adapts to the complex underground environment by changing its spatial modeling and distribution strategies so as to maximize its growth efficiency and slope protection benefits.