Preferential Flow in Soils: Review of Role in Soil Carbon Dynamics, Assessment of Characteristics, and Performance in Ecosystems

Rapid and unstable preferential flow has a significant impact on soil carbon cycle. This review aims to explore the effects of preferential flow on the soil carbon cycle and indicate its characteristics and ecological responses in different ecosystems. This study concluded that preferential flow influences soil carbon cycle through various mechanisms, such as facilitating rapid transport of dissolved organic matter, shaping the distribution and aggregation patterns of soil organic carbon, and enhancing soil microbial activity and organic matter decomposition. The characteristics of preferential flow include surrounding characteristics, rapid non-equilibrium infiltration characteristics, fluctuating characteristics, universal characteristics, lateral infiltration characteristics. Those characteristics could also affect the spatial distribution of soil organic carbon. In addition, this review examines the phenomenon of preferential flow in farmland, forest, wetland, desert, and permafrost ecosystems. Finally, we provide insightful perspectives on future research directions, emphasizing the importance of advancing our understanding of preferential flow mechanisms. It also serves as a valuable resource for future research aimed at unraveling the underlying mechanisms of preferential flow and developing effective soil carbon management strategies.