Afforestation has been viewed as the most effective natural measure to
restore the erosive degraded ecosystems. However, the role of soil
inherent heterogeneity on soil quality and microbial communities in
afforestation remains elusive. Here, three land types of soil were
collected and separated into four aggregate sizes to explore the effects
of afforestation in erosive degraded ecosystem on soil quality and
microbial community at the aggregate level. Afforestation increased soil
aggregate stability and aggregate-associated variance of soil nutrients,
e.g. OM, TN and TP. Compared to the bareland or farmland, four
nutrition-related enzyme activities, including invertase, urease,
alkaline phosphatase and catalase, were significantly enhanced in the
woodland. Interestingly, afforestation promoted the varies of bacterial
alpha-diversity with aggregate size, but had trivial impacts on fungal
alpha-diversity, indicating that the aggregational differentiation of
bacterial alpha-diversity was more sensitive in response to
afforestation than fungal alpha-diversity. For each land-use type, more
fungal taxa variation with aggregate size than bacteria. Afforestation
also enhanced more microbial taxa, especially fungal taxa, were
susceptible to soil aggregate size. Furthermore, afforestation
strengthened bacterial and fungal community dissimilarities between
adjacent aggregates and non-adjacent aggregates. Our findings contribute
to understand the fate of soil quality and microbial communities after
vegetation restoration in degraded ecosystems at the soil aggregate
scale.