Effects of Soil Properties and Tree Species on Root–Soil Anchorage Characteristics

Abstract

Root anchoring provides nonnegligible assistance to prevent soil erosion and stabilize slopes. The anchoring ability of plants suffers a tremendous impact from the soil conditions and the root characteristics. To reveal the root reinforcement effect, a group of pullout tests was conducted on five different tree root systems (Pinus tabulaeformis, Betula platyphylla, Larix gmelinii, Quercus mongolica, and Ulmus pumila) with different soil moisture contents and soil dry weights. The results indicate that the root property (species, diameter, and tensile strength) and soil condition (water content 9.72%, 12.72%, 15.72%, 18.72%, and dry weight 1.32 g/cm3, 1.42 g/cm3, 1.52 g/cm3) had a significant effect on the anchoring effect of the soil. The anchoring effect is more obvious for the roots with a larger diameter and higher tensile strength. With the increase in the soil water content and the dry weight, the root system is more prone to failure but the root anchoring effect of soil with an optimum soil water content performs the best. Among the five different tree species, Pinus tabulaeformis roots were the least effective in anchoring the soil and Betula platyphylla roots performed the best.