[Self-healing properties of lateral-root branches of three shrub species after fracture force injure in semi-arid mining area].

To clarify the sustainable soil reinforcement capacity of the lateral root branches of shrubs after injury by fracture force in a semi-arid coal mining subsidence region of Shendong, we analyzed the ultimate anti-fracture mechanical characteristics of three shrub species, Caragana microphylla, Salix cheilophila, and Hippophae rhamnoides, as well as the self-healing ability of their growth indices and mechanical characteristics after injury by fracture force. The results showed that the anti-fracture force and its strength had significant difference among the three shrub species in their late-ral root branches in the early stage of growing season, with the order of C. microphylla > S. cheilophila > H. rhamnoides. The anti-fracture strengths of C. microphylla and S. cheilophila were positively correlated with the contents of cellulose, lignin and holocellulose, while that of H. rhamnoides was significantly negatively correlated with cellulose and lignin contents, but significantly positively correlated with holocellulose content. The fracture force damage caused by activity in the subsidence area significantly reduced the normal growth and mechanical properties of lateral root branches, which could not return to control levels even after three months of self-healing. For the shrubs, stronger self-healing ability of growth indicators resulted in a higher degree of self-healing of anti-fracture forces. Self-healing ability of growth indicators was in the order of H. rhamnoides (91.2%) > S. cheilophila (82.0%) > C. microphylla (73.9%), and self-healing degree of anti-fracture forces was in the order of H. rhamnoides (41.4%) > S. cheilophila (37.1%) > C. microphylla (30.0%). Sustainable soil reinforcement indices of the shrubs' lateral root branches were in the order of C. microphylla (2.2084) > S. cheilophila (0.2009) > H. rhamnoides (-2.4093). Our results indicated that C. microphylla was the best, S. cheilophila was intermediate, and H. rhamnoides was the least in soil reinforcement in semi-arid coal mining subsidence areas.