A comprehensive review on coupled processes and mechanisms of soil-vegetation-hydrology, and recent research advances

Research on the coupling of soil, vegetation, and hydrological processes is not only a research hotspot in disciplines such as pedology, ecohydrology and Earth system science but also important for achieving sustainable development. However, scientists from different disciplines usually study the coupling mechanism of soil-vegetation-hydrological processes at very different space and time scales, and the mechanistic connections between different scales are quite few. This article reviewed research advances in coupled soil-vegetation-hydrological processes at different spatial scales-from leaf stomata to watershed and regional scales-and summarized the spatial upscaling methods and modeling approaches of coupled soil-vegetation-hydrological processes. We identify and summarize the following coupling processes: (1) carbon-water exchange in leaf stomata and root-soil interface; (2) changes in soil aggregates and profile hydraulic properties caused by plant roots and water movement; (3) precipitation and soil moisture redistribution by plant canopy and root; (4) interactions between vegetation patches and local hydrological process; (5) links between plant community succession and soil development; and (6) links between watershed/regional water budget and vegetation phenology and production. Meanwhile, the limitations and knowledge gaps in the observations, mechanisms, scaling methods, and modeling approaches of coupled soil-vegetation-hydrological processes were analyzed. To achieve a deep integration of various coupling processes across different spatiotemporal scales, future work should strengthen multiscale, multifactor and multiprocess soil-vegetation-hydrology coupling observations and mechanism studies, develop new scaling methods, identify different feedback pathways, and take time-variable plant behavior and soil hydraulic properties into account during modeling.

Automated summary

This article reviews the research advances in coupled soil-vegetation-hydrological processes at different spatial scales and summarizes the spatial upscaling methods and modeling approaches. The article identifies and summarizes the coupling processes and analyzes the limitations and knowledge gaps in observations, mechanisms, scaling methods, and modeling approaches. To achieve a deep integration of various coupling processes across different spatiotemporal scales, future work should strengthen observations and mechanism studies, develop new scaling methods, and consider the effects of plant behavior and soil hydraulic properties.