The Impacts of Riparian Vegetation Buffer Strips on Soil Nitrogen Components and Microbial Communities.

Riparian vegetation buffer strips play a crucial role in soil and water conservation, yet the impact of different vegetation on soil nitrogen components and microbial communities remains poorly understood. This study aimed to evaluate the effects of different riparian vegetation buffer strip on soil organic nitrogen components and microbial communities. Three types of riparian vegetation buffer strips along Taihu Lake in Yixing City (mixed poplar (Populus × euramericana "Nanlin 95") and Taxodium "zhongshanshan" (Taxodium "zhongshanshan"), pure poplar, and pure Taxodium "zhongshanshan") were compared with barren land (HD) as control. Soil nitrogen components, microbial community characteristics, abundance, and their relationships were analyzed across 0-60 cm soil profiles. Results showed that all riparian vegetation buffer strips significantly increased soil total nitrogen (TN) content compared to HD, with content decreasing with soil depth. Riparian vegetation buffer strips significantly enhanced microbial abundance and diversity, with mixed buffer strips exhibiting the highest abundance of Chloroflexi and Acidobacteriota, which contribute positively to nitrogen cycling. RDA revealed that soil nitrogen components and enzyme activities were positively correlated with soil organic carbon (SOC) content but negatively with total potassium (TK) content. The microbial communities in mixed riparian vegetation buffer strips and pure Taxodium "zhongshanshan" buffer strips were closely associated with organic nitrogen parameters (P < 0.05), while communities in pure poplar buffer strips and HD were more related to TK. These findings demonstrate that strategically designed mixed riparian vegetation buffer strips offer superior enhancement of soil nitrogen cycling and microbial diversity compared to pure vegetation buffer strips, these findings provide valuable insights for optimizing riparian vegetation buffer strips design to improve soil quality and nitrogen management in lakeside ecosystems.