[Effect of Nitrogen Addition on Soil Fungal Diversity in a Degraded Alpine Meadow at Different Slopes]

This study proposed nitrogen addition experiments to analyze the effects of exogenous nitrogen addition on soil fungal diversity in alpine meadow. All the experiments were performed in degraded alpine meadow with two different slopes (gentle slope and steep slope) in Guoluo Prefecture of the Sanjiangyuan Region, and the sequence and analysis of ITS of soil fungi were performed using MiSeq PE250 sequencing technology. Comparative analysis was carried out with three nitrogen addition levels on soil fungal diversity in degraded grassland with different slopes, which included low nitrogen (LN, 2 g·m^-2), middle nitrogen (MN, 5 g·m^-2), and high nitrogen (HN, 10 g·m^-2). The results showed that:① the distribution groups of fungi in the soil were Ascomycota, Basidiomycota, Mortierellomycota, and Glomomycota, and the dominant bacteria was Ascomycota. ② The dominant genera were Mortierella and Archaeorhizomyces, and there were no differences in response to different slopes and nitrogen addition levels. ③ A total of 95 genera (Gibberellum, Preussia, etc.) were identified and significantly differed between two different slopes (P<0.05). ④ Bacteria with a relative abundance less than 1% had significant differences in nitrogen addition at different levels on the same slope (P<0.05). 5 In addition, the analyses of α and β diversities showed that soil fungal community structure was stable under different slopes and nitrogen addition levels. Exogenous nitrogen supplementation significantly improved the relative abundance of non-dominant fungal communities without destroying soil fungal community structure.