After years of cultivation, tea garden soils gradually become acidified and compacted. Liming to ameliorate soil acidification alters the soil microbial activity and community structure, ultimately affecting the soil nitrogen cycling and nitrogen use efficiency of tea plants. In this study, ammonium-preferring tea plants (Camellia sinensis) were cultivated in lime-amended soils across a pH gradient (pH 4.5, pH 5.5, pH 6.5, and pH 7.5) to assess the impacts of soil liming on the structure and composition of the rhizosphere microbial community. The results demonstrated that, as the soil pH increased, the diversity and richness of both bacterial and fungal communities exhibited a gradual decline. The biomasses of AOA and AOB were dominated in acid soils and alkaline soils, respectively. The abundance of Proteobacteria, Actinobacteria, and Bacteroidetes in pH 6.5 and pH 7.5 were 16.56–22.56%, 16.29–18.09%, and 1.65–4.52% times higher than those in pH 4.5 and pH 5.5 soils. Ascomycota and Basidiomycota were accounting for 89.93% of all the species. Across the rising pH gradient, the relative abundance of Ascomycota significantly increased by 9.64–20.49%, whereas Basidiomycota decreased by 1.11–15.01%. The RDA analysis results showed the soil pH was the main effect factor for the differences in the structure and composition of bacterial and fungal communities. This conclusion provides theoretical support for the optimization of acidic soil improvement techniques after long-term tea cultivation.

Clarifying carbon (C), nitrogen (N), and phosphorus (P) ecological stoichiometry helps us to understand the ecological functions of wetland ecosystems. This study investigated the variations in ecological stoichiometry and their driving factors in the Yellow River wetland. Soil and plant samples were collected and analyzed from riparian lower-beach wetland (LBW), riparian higher-beach wetland (HBW), and depressional wetland (DW) at the junction of the middle and lower reaches of the Yellow River, respectively. Compared with HBW, DW exhibited higher soil C/N (9.15 ± 0.13), C/P (11.17 ± 0.52), and N/P (1.08 ± 0.09) (p < 0.01), indicating its stronger C and N storage capacity. At the community level, higher plant C/N and C/P in LBW (21.47 ± 1.61 and 206.80 ± 1.75, respectively) and HBW (22.91 ± 0.90 and 241.04 ± 3.28, respectively) compared to DW (14.44 ± 1.02 and 115.66 ± 2.82, respectively) (p < 0.01) suggested that plants in LBW and HBW had greater C assimilation and nutrient use efficiency. Soil electrical conductivity (EC) and hydrolyzed N (SHN) positively affected soil ecological stoichiometry (p < 0.01). In contrast, soil EC, soil organic C, dissolved organic C, and SHN negatively altered plant stoichiometric ratios (p < 0.05), which were regulated by plant functional groups. When pooling all wetlands, stoichiometric ratios of plants were closely correlated with those of soil (p < 0.05). These findings demonstrate that wetland types notably affect soil and plant stoichiometry. Wetland types exerted opposite effects on soil and plant stoichiometry due to the different influences of soil physicochemical properties and the coupling effects of nutrient and stoichiometry between soil and plants. Therefore, the interactions between plant and soil stoichiometry should be considered to explore the C and nutrient cycles in riverine wetlands. Our research emphasizes the necessity of considering wetland type differences and intricate plant–soil stoichiometric interactions in formulating management strategies and maintaining the sustainability of wetlands.