Soil Diversity Distribution Patterns In Response To Erosion-Deposition Processes In Water Erosion Areas Of China

Soil diversity reflects the spatial distribution and variability characteristics of soils,and has an important impact on the composition and spatial distribution of biological communities,as well as the stability of ecosystems.China is rich in soil types in water erosion areas,with diverse landscape types and severe erosion.The dominant factors of erosion,occurrence process and degree of erosion vary greatly in different regions,and the formation process of soil diversity associated with them also varies.Clarifying the role and status of erosion-deposition processes in the spatial distribution pattern of regional soil diversity provides an important scientific basis for maintaining soil ecological functions and protecting soil diversity.In this study,we investigated the spatial distribution patterns of soil diversity in advanced,intermediate and base taxonomic units of soil occurrence classification in China,and investigated the coupling relationship between erosion-sedimentation process and soil diversity of base taxonomic units in small watersheds by using the methods of nuclide tracing,geomorphological restoration,single factor driving and structural equation modeling.and its importance.The main conclusions are as follows:(1)For the sub-basin,erosion-deposition processes change the spatial distribution pattern of soil diversity by changing the thickness of soil layers on a100-year time scale in slopes and small watersheds.For the typical black soil area sub-basin,the erosion-deposition process causes a V-shaped change in soil diversity,and the soil species types in the sub-basin show a shift from "thick soil species" to "medium soil species" and then to "thin soil species " For the typical purple soil area,the erosion-deposition process increases the soil diversity linearly,and the soil species types are more evenly distributed in the sub-basin.The results of the study can provide some reference for the study of soil types and their diversity using thickness as a classification criterion.(2)For the advanced and intermediate classification units,within the water erosion area,the change in soil diversity is more obvious with decreasing classification level for sedimentary plains with large topographic relief or strong agricultural activities;compared to the north,the areas where erosion has an effect on soil diversity are more concentrated in the southern hilly region and the southwestern mountainous region,and in the southern hilly region,erosion has a negative correlation effect on soil diversity,while in the southwestern and The effect of sedimentation on soil diversity is related to the soil classification method and classification level,and its effect size is positively correlated with the proportion of the area occupied by the soil types classified by texture type in accordance with the linear model,and the effect size gradually increases with the decrease of soil classification level.(3)Parent material is the main influencing factor of soil diversity in all regions;in the nine regions where erosion has an impact on soil diversity,erosion is the main impact factor and occupies an important position;the importance of sedimentation in the formation of soil diversity distribution patterns is influenced by soil classification methods and classification levels,and increases with the proportion of the area occupied by soil types classified by texture type,and sedimentation occupies a more important position in the formation of soil diversity at the soil genus level than soil types and subclasses.