半干旱矿区3种灌木侧根分支处折力损伤后的自修复特性

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

以神东矿区用于植被恢复的小叶锦鸡儿、沙柳、沙棘为对象,研究侧根分支处极限抗折力学特性及受力受损后生长指标、力学特性的自修复能力,以明确半干旱采煤沉陷区灌木侧根分支处在遭受外力损伤后的可持续固土能力.结果表明:3种灌木生长季初期侧根分支处极限抗折力和抗折强度均存在显著差异,种间变化均表现为小叶锦鸡儿>沙柳>沙棘.小叶锦鸡儿和沙柳侧根分支处抗折强度与纤维素、木质素及棕纤维素含量呈显著正相关,沙棘抗折强度与纤维素和木质素含量呈显著负相关,与棕纤维素含量呈显著正相关.沉陷区形成的折力损伤显著破坏灌木侧根分支处的正常生长和力学特性,即使通过3个月的自修复也不能恢复到未受损水平.生长指标自修复能力越强,抗折力自修复程度越高,修复率种间变化为沙棘(91.2%)>沙柳(82.0%)>小叶锦鸡儿(73.9%),抗折力修复率种间变化为沙棘(41.4%)>沙柳(37.1%)>小叶锦鸡儿(30.0%).3种灌木侧根分支处可持续固土指数分别为小叶锦鸡儿(2.2084)>沙柳(0.2009)>沙棘(-2.4093),说明在半干旱采煤沉陷区小叶锦鸡儿可持续固土能力最强,沙柳次之,沙棘最弱.

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 antifracture force and its strength had significant difference among the three shrub species in their lateral 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 antifracture 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.