山西土石山区3种草本植物根拉拨特性

为了解山西省土石山区固土护坡草本植物根系拉拔特性，筛选拉拔力优势草本植物物种进行水土流失防治，通过开展根系原位拉拔力学试验，研究了3种典型草本植物香根草（Vetiveria zizanioides L.）、百喜草（Paspalum notatum Flugge）、黑麦草（Lolium perenne L.）根系拉拔力随根径和土层深度的变化规律。结果显示:3种草本植物根系拉拔力随着根径的增大而增加，且拉拔力与根径之间满足幂函数关系；整体上，根系拉拔力从大到小顺序表现为香根草 > 黑麦草 > 百喜草，而且三者之间差异显著；但在D≤0.4 mm和D>0.4 mm两个根径组下，黑麦草均表现出较好的拉拔力性能。在0—10 cm，10—20 cm两个土层间，香根草和百喜草两种植物根系拉拔力性能相似，而黑麦草单根拉拔力在表层土壤发挥效果优于下层土壤。从单根拉拔力方面出发，黑麦草在3种植物中可优先考虑用于固持浅表层土壤。试验探究了草本植物单根在不同根径组下和土层深度下的抗拔性能，研究结果可为山西省土石山区水土保持植物措施草本植物物种选择提供理论依据。

Root Pullout Properties of Three Slope-Protecting Herbaceous Plants in Earth-Rock Mountain Area in Shanxi Province

In order to understand root pullout properties of the herbaceous plants and to select proper species for soil and water conservation in earth-rock mountain area in Shanxi Province, root pullout forces of three plant species, Vetiveria zizanioides L., Paspalum notatum Flugge and Lolium perenne L. were studied by in-situ root pullout tests. The results showed that root pullout forces increased with root diameter and the relationships between root pullout force and root diameters of the three herbaceous plants could be described by power function; the root pullout forces of the three herbaceous plants decreased in the order:Vetiveria zizanioides L. > Lolium perenne L. > Paspalum notatum Flugge, and the differences between them were significant; in D ≤ 0.4 mm and D>0.4 mm root groups, Lolium perenne L. showed better pullout property; root pullout forces of Vetiveria zizanioides L. and Paspalum notatumwere were similar in 0-10 cm and 10-20 cm soil layers, while that of Lolium perenne L. was more effective in 0-10 cm soil layer than 10-20 cm soil layer; according to root pullout force, Lolium perenne L. was a priority among the three species in terms of reinforcing shallow soil with herbaceous plant. The root pullout properties of the three herbaceous plants under different root diameter groups and soil depths were studied, and the results could provide theoretic basis for selecting herbaceous species for soil and water conservation in earth-rock mountain area in Shanxi Province.