Background Power transmission tower bases often cause significant soil disturbance, leading to nutrient depletion and compromised soil quality. Vegetation restoration is increasingly implemented as a sustainable strategy to remediate these impacts; however, its influence on soil enzyme activities and stoichiometric characteristics, key indicators of microbial-mediated nutrient cycling, remains inadequately understood.
Methods We collected soil samples from both disturbed and vegetation-restored sites at transmission tower bases in Yanchi county, Ningxia, focusing on two layers: surface (0–20 cm) and deep (60–80 cm). We evaluated soil physicochemical properties (organic carbon, total nitrogen, and microbial biomass carbon) alongside the activities of extracellular enzymes involved in the carbon (β-1,4-glucosidase, BG), nitrogen (L-leucine aminopeptidase, LAP; β-1,4-N-acetylglucosaminidase, NAG), and phosphorus (acid phosphatase, AP) cycles. We applied enzyme stoichiometry and vector analysis to assess nutrient limitations on soil microbial communities.
Results 1) The results revealed that vegetation restoration markedly enhanced organic carbon, total nitrogen, and microbial biomass carbon in the surface soil, improving 33.36%, 83.66%, and 56.09%, though these parameters decreased with increasing depth. 2) Enzyme activities of BG, NAG, and LAP in the surface layer, as well as BG and NAG in the deep layer, were significantly elevated in the restored areas. Notably, the enzyme C : N ratio declined while the enzyme N : P ratio increased, and stoichiometric vector angles, remaining below 45°, rose following restoration, indicating a predominant nitrogen limitation that gradually diminished. 3) Redundancy analysis showed that soil physiochemical properties explained the changes of enzyme activity and ecological stoichiometric traits in 71.94% surface soil and 68.14% deep soil, respectively, and total nitrogen and the soil C : N ratio, were the primarily drivers in surface soil, whereas organic carbon and microbial biomass carbon were the key drivers in deep soil.
Conclusions In conclusion, the alterations in soil enzyme activities and their stoichiometric characteristics during vegetation restoration process at Ningxia transmission tower bases reveal the nutrient cycling mechanisms mediated by microbial activity. This study elucidates the mechanisms by which vegetation restoration modulates microbial nutrient cycling at power transmission tower bases and thus provides a robust framework for assessing its ecological benefits in arid and semiarid environments.
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