植物根系固坡抗蚀的效应与机理研究进展

植物根系对抵抗坡体浅层滑坡和表土侵蚀起着巨大的作用.植物根系通过增强土体的抗剪强度发挥固坡效应.目前有关植物根系固坡机理的模型较多,普遍接受的是Wu-Waldron模型.该模型表明,植物根系产生的土体抗剪强度的增量与根系的平均抗拉强度和根面积比成正比,应用该模型评价根系固坡效应的2个最重要因素是根系的平均抗拉强度和根面积比.研究发现,土壤抗侵蚀性随着植物根系数量的增加而提高,但未有一致的定量函数关系.植物根系提高土壤抗侵蚀性主要通过直径小于1mm的须根起作用.须根通过增加土壤水稳性团聚体的数量与粒径等作用来提高土壤的稳定性,以抵抗水流分散;须根还能有效地增强土壤渗透性,减少径流,从而达到减少土壤冲刷的目的.

Effects and mechanisms of plant roots on slope reinforcement and soil erosion resistance: A research review.

Plant roots play an important role in resisting the shallow landslip and topsoil erosion of slopes by raising soil shear strength. Among the models in interpreting the mechanisms of slope reinforcement by plant roots, Wu-Waldron model is a widely accepted one. In this model, the reinforced soil strength by plant roots is positively proportional to average root tensile strength and root area ratio, the two most important factors in evaluating slope reinforcement effect of plant roots. It was found that soil erosion resistance increased with the number of plant roots, though no consistent quantitative functional relationship was observed between them. The increase of soil erosion resistance by plant roots was mainly through the actions of fiber roots less than 1 mm in diameter, while fiber roots enhanced the soil stability to resist water dispersion via increasing the number and diameter of soil water-stable aggregates. Fine roots could also improve soil permeability effectively to decrease runoff and weaken soil erosion.