LAUSR

Abstract The mechanism of soil structure stabilization has been rarely investigated from the perspectives of both soil material composition and porosity due to the complexity of soil structure and its formation process. Here, the relative importance of soil physicochemical properties in aggregate stability was evaluated for soils with different weathering degrees. Typical zonal soils derived from quaternary clay were collected from central to south China with increasing precipitation and temperature. Aggregate stability against slaking (MWDFW), mechanical breakdown (MWDWS) and swelling (MWDSW) was determined, as well as basic properties (including clay content, soil organic matter (SOM), different forms of sesquioxides and pore size distribution (PoSD)). The degrees of soil weathering increased from central to south China with increasing free oxides content. PoSD in the eluvium (A) horizon exhibited triple and double peaks, indicating the decreasing heterogeneity of pore structures, while that in parent material (C) horizon was dominantly characterized by textural pores (