[Characteristics of Nitrogen Cycle-related Bacterial Community and Its Response to Soil in the Main Lead-zinc Mine Reclamation Area of Lanping]

The nitrogen cycle has an important impact on the element cycle of the soil ecosystem. Moreover, it is important to clarify the key environmental factors of nitrogen cycle microorganisms for ecological restoration in mining areas. The functional flora can regulate the growth of vegetation by participating in the biogeochemical cycle of soil elements in the mining area, which is beneficial to the reclamation of the mining area. The Lanping lead-zinc mine is the largest open-pit lead-zinc mining area in Asia. The content of Cd in the soil of the mining area was 95.6-388.7 times the background value of heavy metal content in Yunnan Province, and it is urgent to carry out ecological restoration in the mining area. To explore the response of nitrogen cycling bacteria to the soil in a lead-zinc mine reclamation area, soil samples from the Lanping lead-zinc mine reclamation area were considered as the research object, and the effects of different nutrient gradients on nitrogen cycling functional microbial groups in the Lanping lead-zinc mine reclamation area were revealed using 16S rRNA high-throughput sequencing technology, collinear network analysis, PCoA, Mantel test, and random forest. The results showed that the dominant bacteria were all from the unmarked species of Nitrosomonadaceae. The effect of lead and zinc on nitrogen cycling functional microorganisms in the lead-zinc mining area was limited, and the effects of organic matter and pH were greater. Ammonium nitrogen （NH₄⁺-N）, nitrate nitrogen （NO₃^--N）, and pH were the key physical and chemical factors affecting nitrification, denitrification, and nitrogen-fixing microorganisms, respectively.