Effects of Different Vegetation Types on Soil Quality in Golden Huacha (Camellia petelotii) National Nature Reserve

Abstract

Natural and planted forests differentially regulate soil quality through vegetation–soil interactions. The effects of four types of planting covers on soil nutrients, enzyme activities, and microbial communities in the Guangxi Camellia nitidissima National Nature Reserve were studied, revealing the multi-dimensional influences of natural (broadleaf, shrubland) and planted forests (bamboo, pine) on soil quality. Surface soils (0–10 cm depth) were characterized for physicochemical properties (pH, TC, TN, NO3−-N, AP), enzyme activities (α-amylase, urease, phosphatase, β-glucosidase), and microbial composition (using 16S rRNA and ITS region sequencing). Mantel tests and PLS–PM modeling were employed to investigate interactions among vegetation, soil variables, and microbes. Natural forests exhibited higher pH, nitrate nitrogen, and enzymatic activities (urease, phosphatase, β-glucosidase) alongside enhanced carbon–nitrogen accumulation and reduced acidification. Planted forests showed elevated available phosphorus and nutrient supply but lower organic matter retention. Microbial communities displayed higher similarity within natural forests, with fungal composition strongly linked to total carbon/nitrogen (p < 0.05). Vegetation type positively influenced bacterial diversity but negatively affected fungal communities. Natural forests maintained critical soil–microbe–plant interactions supporting ecosystem resilience through carbon–nitrogen cycling, while planted forests fostered divergent microbial functionality despite short-term nutrient benefits. These findings underscore natural forests’ unique role in preserving ecological stability and reveal fundamental limitations of artificial systems in mimicking microbially-mediated biogeochemical processes. Conservation policy should prioritize the protection of natural forests while simultaneously integrating microbial community management with vegetation restoration efforts to enhance long-term ecosystem functionality and nutrient cycling efficiency.