State Key Laboratory of Eco-hydraulics in Northwest Arid Region of China, Xi'an University of Technology, Xi'an 710048, Shaanxi, China; Key Laboratory of National Forestry Administration on Ecological Hydrology and Disaster Prevention in Arid Regions, Xi'an University of Technology, Xi'an 710048, Shaanxi, China.
State Key Laboratory of Eco-hydraulics in Northwest Arid Region of China, Xi'an University of Technology, Xi'an 710048, Shaanxi, China; Key Laboratory of National Forestry Administration on Ecological Hydrology and Disaster Prevention in Arid Regions, Xi'an University of Technology, Xi'an 710048, Shaanxi, China.
Sci Total Environ. 2024 Dec 1;954:176211. doi: 10.1016/j.scitotenv.2024.176211. Epub 2024 Sep 12.
Vegetation restoration is an effective and important measure for controlling soil erosion in arid and -arid regions. Both its aboveground and underground parts play a crucial role in controlling surface runoff and soil detachment on slopes. But how much the parts of vegetation contribute to the runoff and sediment reducing benefits of rill erosion on slopes is unclear. We used grassland slopes at four successional stages for simulated scouring experiments to observe how successional vegetation community structures, root characteristics, and soil structures contribute to erosion and sand production. Initial flow production time increased, and total runoff decreased. Under the scour intensities, the 11-year slope had the lowest flood peak and volume and the greatest runoff reduction benefit. The 25-year slope had the lowest sand peak and volume and the greatest sediment reduction benefit. As scour intensity increased, runoff reduction effect of vegetation at the successional stages decreased; the sediment reduction benefit remained high. PLS-PM analysis showed that the indirect effects of the aboveground and underground parts of vegetation on sand production were -0.364 and -0.439, respectively. Aboveground parts mainly embodied the regulation of runoff, in which stem count, humus mass, and biomass were the main factors affecting runoff and sand production. Underground parts mainly reflected their soil structure improvement, in which root volume density, root surface area density, and root mass density are the main explanatory variables. The direct effects of runoff and soil structure on slope rill erosion were 0.330 and -0.616, respectively, suggesting the stability of soil structure is the primary factor affecting the sand production, not erosion energy. The results provide a reference for scientific assessment of the key role of natural vegetation restoration in regional soil erosion control and the development of biological measures for soil and water conservation on the slopes of the Loess Plateau.
植被恢复是干旱和半干旱地区控制水土流失的有效且重要的措施。植被的地上和地下部分在控制坡面地表径流和土壤剥蚀方面都起着至关重要的作用。但是，植被的各个部分对坡面细沟侵蚀的径流量和泥沙减少效益的贡献有多大尚不清楚。我们使用了四个演替阶段的草地坡面进行模拟冲刷实验，以观察演替植被群落结构、根系特征和土壤结构如何促进侵蚀和产沙。初始产流时间增加，总径流量减少。在冲刷强度下，11 年的坡面具有最低的洪峰和洪量以及最大的径流减少效益。25 年的坡面具有最低的沙峰和沙量以及最大的泥沙减少效益。随着冲刷强度的增加，演替阶段植被的减流效果降低；泥沙减少效益保持较高水平。PLS-PM 分析表明，植被地上和地下部分对产沙的间接影响分别为-0.364 和-0.439。地上部分主要体现了对径流的调节，其中茎数、腐殖质质量和生物量是影响径流和泥沙产生的主要因素。地下部分主要反映了其土壤结构的改善，其中根体积密度、根表面积密度和根质量密度是主要的解释变量。径流和土壤结构对坡面细沟侵蚀的直接影响分别为 0.330 和-0.616，这表明土壤结构的稳定性是影响产沙的主要因素，而不是侵蚀能量。研究结果为科学评估自然植被恢复在区域水土流失控制中的关键作用以及黄土高原坡面土壤和水保持生物措施的发展提供了参考。
