Effects of drawing damage on root growth and soil reinforcement of in a coal mining subsidence area.

Roots can effectively consolidate and support the soil and are affected by external forces. To identify the survival strategies and soil reinforcement capability of roots against damaging forces, we investigated taproots with a diameter of 1-4 mm in a coal mining subsidence area. To simulate root damage from erosion, an HG100 digital push&pull tester and self-developed experimental installation were used in situ. Relative growth rate, activity, tensile force, and strength of taproots were inhibited by damage. Significant differences occurred in these indicators depending on drawing damage type and level. Inhibition effects from persistent drawing damage on growth and tensile properties were markedly greater than those from instantaneous drawing. Inhibition effects of severe damage were markedly greater than those of mild damage. The number of living roots declined more after persistent drawing or severe injury than after instantaneous or mild damage. The taproots showed self-healing ability, and the inhibitory effect of drawing damage gradually weakened with the time of self-repair, ensuring taproots could continue to play a role in soil reinforcement. The self-healing ability of roots should be considered in vegetation restoration of erosion-prone areas to ensure that the roots' ability to resist erosion is accurately estimated. Research on the soil reinforcement ability of damaged plant roots is very limited at present. This study provides a new perspective for soil reinforcement: roots can be destroyed by erosional forces while providing support for soil, the self-healing ability of plants determines whether they can provide effective support for soil in the erosive environment.