三峡水库消落带土壤团聚体微结构变化特征  

Change Features of Soil Aggregate Microstructure in the Water-level Fluctuation Zone of the Three Gorges Reservoir,China

作　　者：张淑娟[1,2] 贺秀斌 鲍玉海[1] 唐强[1] ZHANG Shujuan;HE Xiubin;BAO Yuhai;TANG Qiang(Key Laboratory of Mountain Surface Processes and Ecological Regulation,Institute of Mountain Hazards and Environment,Chinese Academy of Sciences,Chengdu 610041,China;University of Chinese Academy of Sciences,Beijing 100049,China)

机构地区：[1]中国科学院、水利部成都山地灾害与环境研究所山地表生过程与生态调控重点实验室,成都610041 [2]中国科学院大学,北京100049

出　　处：《山地学报》2020年第3期360-370,共11页Mountain Research

基　　金：国家自然科学基金(41771321,41771320,41571278)。

摘　　要：三峡水库落差30 m的反季节水文节律使消落带的地形、植被和土壤发生了巨大变化,特别是土壤团聚体微结构对干湿交替作用极为敏感。为了明确三峡水库消落带水位周期性涨落对土壤团聚体微结构的影响,采集消落带145~155 m、155~165 m、165~175 m的表层土壤,以未淹水高程180 m的土壤为对照,采用同步辐射显微CT及图像处理技术,对土壤团聚体微结构变化特征进行分析。结果表明:(1)团聚体孔隙度随水位高程的降低而显著降低,与180 m的孔隙度相比,165~175 m、155~165 m和145~155 m的孔隙度依次降低了21.80%、47.68%和59.58%;孔隙数量和孔隙节点数量随水位高程的降低显著减少,最大降幅分别为56.64%和91.18%;孔隙分形维数随水位高程降低而降低,欧拉值则随水位高程的降低而增大;(2)团聚体孔隙度以>100μm的通气孔隙度为主,随着水位高程的降低,通气孔隙度逐渐降低,而<30μm的贮存孔隙度和30~100μm的毛管孔隙度先增加后降低;(3)团聚体孔隙形状以瘦长型孔隙为主,随着水位高程的降低,瘦长型孔隙占孔隙度的百分比显著降低,而规则孔隙和不规则孔隙占孔隙度的百分比显著增加。三峡水库消落带水位周期性涨落对团聚体孔隙数量、大小分布、形状特征等影响显著,团聚体孔隙特征参数随水位高程的变化,主要受淹水时间、淹水深度和干湿交替等因素的影响。研究结果可为三峡水库消落带土壤抗蚀能力及岸坡稳定性评价提供依据。The 30-m water-level fluctuation had led to complicated changes in terrain, vegetation and soil, especially soil aggregate microstructure in the riparian zone of the Three Gorges Reservoir. In order to clarify the influence of periodic water-level fluctuation on soil aggregate microstructure in the Three Gorges Reservoir, the topsoil samples were collected from three different water levels of the riparian zone(145~155 m, 155~165 m, 165~175 m) and from the bank uplands(180 m). Soil at 180 m was used as a reference group since it was not subjected to inundation. In this study, synchrotron-based X-ray micro-computed tomography and digital image analysis techniques were used to analyze the change features of soil aggregate microstructure. The results showed that:(1) Soil aggregate porosity decreased significantly with the decrease of water levels. Compared with the porosity of 180 m, the porosities of 165~175 m, 155~165 m and 145~155 m decreased by 21.80%, 47.68% and 59.58%, respectively. Pore number and pore node number decreased significantly with the decrease of water levels, and the maximum reductions were 56.64% and 91.18%, respectively. Pore fractal dimension decreased with the decrease of water levels, while Euler number increased with the decrease of water levels.(2) The porosity was mainly comprised of non-capillary porosity that diameter larger than 100 μm, accounting for more than 90% of the total porosity. With the decrease of water levels, both the storage porosity of <30 μm and the capillary porosity of 30~100 μm increased firstly and then decreased, while the non-capillary porosity of >100 μm was significantly reduced.(3) The pores were dominated by the elongated pores. With the decrease of water levels, the percentages of regular and irregular porosities increased significantly, while the percentage of elongated porosity decreased. It can thus be deduced that periodic water-level fluctuation of the Three Gorges Reservoir had significant effects on aggregate pore number, pore size distribution, and

关 键 词：团聚体 微结构 同步辐射显微CT 消落带 三峡水库 

分 类 号：S152.4[农业科学—土壤学]