期刊
GEODERMA
卷 385, 期 -, 页码 -出版社
ELSEVIER
DOI: 10.1016/j.geoderma.2020.114883
关键词
Structural equation modelling; Flooding intensity; Plant community; Soil physicochemical property; Environmental stress; Three Gorges Dam
类别
资金
- National Natural Science Foundation of China [41771266, 41401243]
- Research Fund of State Key Laboratory of Soil and Sustainable Agriculture, Nanjing Institute of Soil Science, Chinese Academy of Science [Y812000005]
- Youth Innovation Promotion Association of the Chinese Academy of Sciences [2017391]
- China Scholarship Council (CSC)
- Technology Innovation and Application Development Project of Chongqing [cstc2019jscx-dxwtBX0007]
- Chongqing Municipal Bureau of Science and Technology [cstc2020jcyj-zdxmX0018]
- University of Manchester
The study found that soil aggregate stability decreases with increasing flooding intensity, which is a major determinant of soil aggregation. Increased soil water content also significantly contributes to the decrease in aggregate stability, while soil organic matter and total nitrogen contents are associated with an increase in aggregate stability. Vegetational properties, such as aboveground biomass, plant species richness, and plant functional types, play a role in explaining soil aggregation.
Riparian zone is an ecotone between aquatic and terrestrial ecosystems, where soil aggregate stability is fundamental in supporting ecosystem functions and associated services. Yet, little is known about the resilience of riparian soil aggregate stability along a gradient of flooding stress. Here, we studied a riparian ecosystem across hillslopes in an early successional stage (a grass-dominated successional stage) along a gradient of flooding intensity (FI) of a hydrological regime triggered by operation of the Three Gorges Dam (TGD), China, which is one of the biggest dams in the world. Size distribution and stability of soil aggregates were tested by the wetsieving method. Path analysis and structural equation modelling (SEM) were applied to determine the contributions of abiotic and biotic factors (including environmental variables, soil physicochemical properties, vegetational properties) to soil aggregate stability. Results showed that soil aggregate stability decreased with FI (a ratio of flooded days to whole days) which was a major determinant of soil aggregation. Also, increasing soil water content (SWC) greatly contributed to the decrease of aggregate stability, while contents of soil organic matter and total nitrogen correlated with an increase of aggregate stability. In terms of vegetational properties, aboveground biomass, plant species richness, and plant functional types partially explained soil aggregation. Significantly, distribution of the riparian dominant pioneer species, Cynodon dactylon, was affected by FI and SWC, and a higher density of the species led to a lower amount of small macro-aggregates (0.25-2 mm). Our study reveals that the soil stabilizing process is mainly governed by FI and edaphic factors, although vegetational properties have potentials to influence the soil aggregate stability. Our study highlights the vital processes for ecological restoration of riparian ecosystem in an early successional stage under a drastic change in hydrological regime.
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