Bacterial developmental processes and driving factors in the formation of mineral sand soils

Soil formation is a complex process that begins with biological evolution, and the maturation process of infertile soil demands an appreciable temporal expanse. Although anthropogenic interventions have proven effective in speeding up soil maturation, our understanding of their timing and their connection to broader ecological principles in soil biological development is still incomplete. In this study, we conducted a 150-day microcosmic experiment with the addition of sludge and/or fermented wood chips (FWC) to mineral sand soil. The results revealed that both sludge and FWC increased the availability of Carbon, nitrogen and potassium nutrients, as well as the activity of cellulase and microbial biomass carbon (MBC). They also promoted soil aggregation and increased bacterial diversity. Furthermore, soil biological development contributed to the complexity of the bacterial ecological network and enhanced ecosystem functionality and stability. Even though both sludge and FWC promoted the soil maturation, they showed distinct mechanistic action for promoting soil maturation, with sludge enhancing the physical structure, and FWC changing chemical composition. Specifically, the addition of sludge facilitated a transition in bacterial community function from nitrogen heterotrophy and reduction process to nitrogen assimilation and oxidation process. The addition of FWC induced a transition in bacterial community function from nitrogen cycling to carbon cycling, concurrently enhancing autotrophic and heterotrophic-related functions. It is also worth emphasizing that sludge and FWC exhibited a synergistic effect in promoting biological development, thereby providing an effective avenue for soil maturation.