Hubei International Scientific and Technological Center of Ecological Conservation and Management in the Three Gorges Area, China Three Gorges University, Yichang, 443002, Hubei, People's Republic of China.
Engineering Research Center of Eco-Environment in the Three Gorges Reservoir Region, Ministry of Education, China Three Gorges University, Yichang, Hubei, 443002, People's Republic of China.
Sci Rep. 2020 Nov 24;10(1):20462. doi: 10.1038/s41598-020-77407-1.
Elymus nutans is an herbaceous plant that can be used to restore degraded alpine and subalpine ecosystems. Here, we evaluated how sowing density affects soil reinforcement and slope stabilization properties of vegetation-concrete structures. To investigate the optimal sowing density of E. nutans in vegetation-concrete applications for slope protection, six experimental treatments were established with different plant densities: control, I (1100 seeds/m), II (2200 seeds/m), III (3300 seeds/m), IV (4400 seeds/m), and V (5500 seeds/m). Several parameters of plant growth in addition to soil reinforcement and slope stabilization properties were measured in each treatment, as well as the associations among parameters. As density increased, aboveground biomass continually increased, and plant heights, root surface areas, root lengths, and underground biomass all first increased and then decreased. In contrast, tiller numbers and the average root diameter gradually decreased with increasing density. Increased density also resulted in increased maximum water interception levels by aboveground stems and leaves. The maximum water interception by the aboveground stems and leaves was 41.75% greater in the highest density treatment (V) compared to the lowest density treatment (I). However, the enhancement of erosion resistance and soil shear strength first increased and then decreased as density increased, with maximal values observed in the medium-high density treatment (IV). Sowing density was highly correlated with aboveground biomass, plant heights, tiller numbers, and the maximum level of water interception by stems and leaves. Thus, sowing density directly influenced soil reinforcement and slope stabilization properties of aboveground plant components. However, density was not significantly correlated with belowground biomass, root lengths, root surface areas, the enhancement of erosion resistance, and soil shear strengths. Therefore, sowing density indirectly influenced soil reinforcement and slope stabilization of belowground plant components. Following from these results, we suggest that the optimal sowing density of E. nutans is approximately 4400 plants/m in their application within vegetation-concrete structures used for slope protection.
垂穗披碱草是一种草本植物，可用于恢复退化的高山和亚高山生态系统。在这里，我们评估了播种密度如何影响植被-混凝土结构的土壤加固和边坡稳定特性。为了研究垂穗披碱草在植被-混凝土边坡防护应用中的最佳播种密度，我们设置了 6 个不同的播种密度处理实验，分别为对照、I（1100 粒/米）、II（2200 粒/米）、III（3300 粒/米）、IV（4400 粒/米）和 V（5500 粒/米）。在每个处理中，我们测量了植物生长的几个参数，以及土壤加固和边坡稳定特性，并分析了参数之间的关系。随着密度的增加，地上生物量持续增加，株高、根表面积、根长和地下生物量均先增加后减少。相反，分蘖数和平均根直径随密度的增加而逐渐减小。增加密度还导致地上茎和叶的最大水分截留量增加。与最低密度处理（I）相比，最高密度处理（V）的地上茎和叶的最大水分截留量增加了 41.75%。然而，随着密度的增加，抗侵蚀能力和土壤抗剪强度的增强先增加后减少，在中高密度处理（IV）中达到最大值。播种密度与地上生物量、株高、分蘖数和茎叶最大水分截留量高度相关。因此，播种密度直接影响地上植物构件的土壤加固和边坡稳定特性。然而，密度与地下生物量、根长、根表面积、抗侵蚀能力增强和土壤抗剪强度无显著相关性。因此，播种密度间接地影响地下植物构件的土壤加固和边坡稳定。根据这些结果，我们建议垂穗披碱草在植被-混凝土结构中用于边坡防护的最佳播种密度约为 4400 株/米。
