Nsabimana Gratien, Hong Li, Yuhai Bao, de Dieu Nambajimana Jean, Jinlin Li, Ntacyabukura Tite, Xiubin He
Key Laboratory of Mountain Surface Processes and Ecological Regulation, Institute of Mountain Hazards and Environment, Chinese Academy of Sciences, Chengdu, 610041, Sichuan, PR China; University of Chinese Academy of Sciences, 100049, Beijing, China.
Key Laboratory of Mountain Surface Processes and Ecological Regulation, Institute of Mountain Hazards and Environment, Chinese Academy of Sciences, Chengdu, 610041, Sichuan, PR China.
Environ Res. 2023 Jan 15;217:114928. doi: 10.1016/j.envres.2022.114928. Epub 2022 Nov 23.
Spatial hydrological alterations can affect soil structural stability. Over time, forces induced by water weaken soil aggregates and this has a negative implication to soil health. The Three Gorges Reservoir (TGR) in particular, experienced a long-term hydrological condition and repetitive seasonal water level fluctuations that could affect soil health. The present study was conducted to investigate the effects of different water levels on soil aggregate disintegration rate over time and its relation to soil erosion susceptibility in water reservoirs. Samples from different elevations (155 m, 160 m, 163 m, 166 m, 172 m, and 180 m) in the water level fluctuation zone (WLFZ) were exposed to continuous wet-shaking for 3, 9, 27, 54, and 81 min resulted to different WLF intensity accordingly. The results showed a comparative difference between aggregates size before and after the experiment where micro-aggregates (<0.25 mm) increased with respect to elevations increase. The exponential prediction proved that aggregate stability decreased with the increase of WLF intensity, insisting the effects of continuous hydrological stress to aggregate break-down. A couple of factors definitely confirmed that soil erodibility (k) is primarily determined by disintegration of soil aggregates for the surface soil of the TGR. Despite the fact that Disintegration rate (Dr) and k showed a positive relationship, R = 0.73 (p < 0.05), the results showed that the soil properties decreasing Dr also decreases soil erodibility in the study area. Non-effective role of soil organic matter (SOM) for stabilizing soil aggregates was primarily related to water level fluctuations inhibiting decomposition. Relying on the present findings, environmental problems mostly soil erosion in the TGR could be therefore linked to excessive destabilization of soil aggregates. Therefore, the results of this study should play a major role in determining the factors primarily inducing soil erosion in river reservoirs.
空间水文变化会影响土壤结构稳定性。随着时间的推移，水产生的作用力会削弱土壤团聚体，这对土壤健康有负面影响。特别是三峡水库（TGR），经历了长期的水文状况和反复的季节性水位波动，可能会影响土壤健康。本研究旨在调查不同水位随时间对土壤团聚体崩解速率的影响及其与水库土壤侵蚀敏感性的关系。从水位波动带（WLFZ）不同海拔（155米、160米、163米、166米、172米和180米）采集的样本连续湿摇3、9、27、54和81分钟，相应地产生了不同的WLF强度。结果表明，实验前后团聚体大小存在比较差异，其中微团聚体（<0.25毫米）随海拔升高而增加。指数预测证明，团聚体稳定性随WLF强度的增加而降低，这表明持续的水文应力对团聚体分解有影响。几个因素明确证实，三峡水库表层土壤的土壤可蚀性（k）主要由土壤团聚体的崩解决定。尽管崩解速率（Dr）和k呈正相关，R = 0.73（p < 0.05），但结果表明，降低Dr的土壤性质也会降低研究区域的土壤可蚀性。土壤有机质（SOM）对稳定土壤团聚体的无效作用主要与水位波动抑制分解有关。基于目前的研究结果，三峡水库的环境问题（主要是土壤侵蚀）可能与土壤团聚体的过度失稳有关。因此，本研究结果在确定主要导致河流水库土壤侵蚀的因素方面应发挥重要作用。
