Abstract: Pavements change the structure and function of soil microbial community, which is adverse to soil bacterial community. To evaluate the effects of pavements on the vertical distribution of soil bacterial communities, an experiment was conducted to simulate the in-situ conditions of pervious pavement (PP), impervious pavement (IPP), and non-pavement (NP) by planting typical greening tree species in Beijing (Pinus tabuliformis, Fraxinus chinensis, and Acer truncatum). Soil samples were collected from five layers (0-20, 20-40, 40-60, 60-80, 80-100 cm) and the composition and diversity of soil bacterial community were determined by 16S amplicon sequencing method. The results showed that: (1) PP decreased the relative abundance of Acidobacteria in 0-60 cm soil layer. IPP increased the relative abundance of Gemmatimonadetes and Acidobacteria in 0-20 cm soil layer and Proteobacteria in 60-100 cm soil layer. (2) The effects of pavement on α diversity of the three tree species were as follows: Pinus tabuliformis <Fraxinus chinensis < Acer truncatum, with greater effects on the deep soil across all the species. Both PP and IPP significantly decreased the diversity of bacterial Chao1 in the 40-60 cm soil layer under Fraxinus chinensis and 20-40 cm soil layer under Acer truncatum. PP significantly decreased Shannon index in 60-100 cm soil layer under Pinus tabuliformis, 20-40 and 80-100 cm soil layer under Acer truncatum, and decreased Chao1 diversity in 80-100 cm soil layer of Acer truncatum. IPP significantly increased Chao1 diversity in 80-100 cm soil layer of Acer truncatum. (3) Soil bacterial community under pavements was positively correlated with soil pH, total carbon, total nitrogen, ammonium, available phosphorus and available potassium. Soil bacterial α diversity was positively correlated with ammonium and available phosphorus in 20-60 cm soil layer, while Shannon index was positively correlated with soil total carbon in 80-100 cm soil layer. The α diversity of soil bacteria was negatively correlated with total nitrogen, organic matter, nitrate and available potassium in the 60-100 cm soil layer, while the diversity of soil bacteria Chao1 was negatively correlated with ammonium nitrogen in the 0-20 cm soil layer. Overall, pavements had a negative effect on soil bacteria, with the effect in the deep layer being greater than that in the surface soil. PP could alleviate the negative effect to a certain extent. Our results can provide a theoretical basis for reasonably evaluating soil ecosystem function of urban green space.

Key words: pavement, 16S rRNA, bacterial diversity, soil layer