Effect and mechanisms of conifer and broadleaf mixtures on the soil characteristics in limestone mountains

: In restoring the limestone mountain ecosystem, the core scientific issue for achieving ecological restoration and ecosystem stability lies in understanding the interaction mechanism between vegetation and soil. To address this, we focused on four types of artificial forest communities, each 30 years old, with varying ratios of coniferous and broad-leaved trees (0%–20%, 20%–50%, 50%–80%, 80%–100%) in typical limestone mountainous areas of the northern subtropical region. These forest communities were selected as research subjects to assess understory vegetation diversity, litter fall, and fine root characteristics. The study investigates the influence of various mixing ratios on the restoration of understory vegetation and soil systems. The findings reveal significant differences in litter fall stock, water capacity, annual decomposition rate, nutrient change rate, and fine root biomass of litter fall among different mixing proportions. With an increase in the proportion of coniferous trees, both standing litter fall and annual yield exhibit a decrease. Consequently, an effective strategy for restoring and enhancing fragile ecosystems in limestone mountainous areas involves establishing mixed forests or conducting forest transformations based on a moderate mixing proportion.