Soil aggregates are the basic unit structing soils, and their stability
is an important index for soil degradation. However, current
methodologies rarely assess the influence of primary soil particles on
soil aggregates distribution for different breakdown mechanisms. The
purpose of this study was to fill this gap in the literature by
developing a new method that separates the primary soil particles from
the soil aggregates for different breakdown mechanisms with a series of
in-lab experiments. The whole soil sample was treated by fast wetting,
slow wetting, and mechanical breakdown by pre-wetting and stirring to
simulate the different breakdown mechanisms of slaking, differential
swelling of clays, and mechanical breakdown by raindrop impact,
respectively. Then, attempts were made to separate the primary soil
particles from the soil aggregates of various particle size fractions by
using sodium hexametaphosphate and hydrogen peroxide to eliminate the
influence of the primary soil particles on the soil aggregate
distribution. Four soils collected from different areas with different
soil textures were used to assess the soil aggregate distribution by
using the new method to highlight the importance of separating the
primary soil particles from the soil aggregate for different breakdown
mechanisms. The results indicated that the primary soil particles have
much greater influence on the micro-aggregates than on macro-aggregates.
Different breakdown mechanisms and soil types could affect the influence
of the primary soil particles affects the on soil aggregate
distribution. This study highlights the influence of separate primary
soil particles on soil aggregate distribution for different breakdown
mechanisms.