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[Objective] The spatial distribution characteristics of surface soil particles under different vegetation patterns at Pisha sandstone area in tipical area in Ordos City, Inner Mongolia Autonoous Region, and the sorting and transportation mechanisms of water erosion for soil particles were studied in order to provide a theoretical basis for the restoration of the ecological environment in this area. [Methods] The study was conducted with in-situ monitoring of field runoff plots. The effects of different vegetation patterns on the spatial distribution of surface soil particles on Pisha sandstone slopes under natural rainfall conditions were determined by combining three-dimensional laser scanning and geostatistics. [Results] ① The uniformly distributed vegetation pattern effectively inhibited runoff and sediment production on the slope. The erosion area, average runoff, and average sediment volume were 5.35%, 63.16%, and 76.47%, respectively, lower than observed for the bare slope. ② Under the uniformly distributed vegetation pattern, the contents of soil clay and silt particles were 1.3% and 2.2%, respectively, greater after rain than before rain, and sand content was 3.2% lower. The content of sand particles increased after rain by 5.8% and 15.3% in the randomly distributed and aggregated vegetation patterns respectively, resulting in a coarsening of soil texture. ③ Different vegetation patterns were the main factors causing the spatial variation of soil particles. The uniformly distributed and randomly distributed vegetation patterns increased the nugget coefficients of silt and sand particles after rainfall, and decreased the spatial autocorrelation. The aggregated vegetation pattern decreased the nugget coefficients of clay and silt particles from 95.06% and 83.89% to 0.07% and 0.06%, showing a strong spatial autocorrelation. [Conclusion] A uniformly distributed vegetation pattern produced suitable soil and water conservation benefits on an arsenic sandstone slope, significantly reducing runoff and sediment production and inhibiting soil coarsening.

Natural rainfall affects the stability of soil aggregates by the kinetic energy of the rain changing the morphological characteristics of slope micro-topographic factors. Although the relationship between the stability of soil aggregates and micro-topography is not very significant at the slope scale, there are also rules to be found. This study aims to explore the relationship between slope micro-topography and aggregate stability, and to observe the spatial distribution of aggregate stability after water erosion. In this study, a digital elevation model of slope micro-topography was established by using a three-dimensional laser scanner to observe the slope erosion changes after rainfall events and clarify the spatial changes of soil aggregate stability and its relationship with slope micro-topography by combining geostatistics and generalized additive model (GAM). The results showed that the area of serious water erosion in the lower part of the slope accounted for 38.67% of the slope, and the micro-topography index of the slope changed obviously after rainfall, with the slope increasing by 3.1%, the surface roughness increasing by 5.34%, the surface cutting degree increasing by 26.67%, and the plane curvature decreasing by 61.7%. In addition, the GAM model was used to fit the multivariate variables. The results revealed that the slope and surface roughness were the key factors affecting the stability of water-stable aggregate. The slope and surface roughness were negatively correlated with the stability of water-stable aggregates. [ABSTRACT FROM AUTHOR]