Welcome to Chinese Journal of Applied Ecology! Today is Share:

Chinese Journal of Applied Ecology ›› 2023, Vol. 34 ›› Issue (6): 1525-1532.doi: 10.13287/j.1001-9332.202306.004

• Original Articles • Previous Articles     Next Articles

Effects of vegetation and soil changes on microbial biomass carbon and nitrogen in the Napahai meadow under N deposition

LYU Jinghua1,2, ZHAO Xuyan3, LU Mei1*, LI Cong4, YANG Zhidong1, LIU Pan1, CHEN Zhiming3, FENG Jun5   

  1. 1College of Ecology and Environment, Southwest Forestry University, Kunming 650224, China;
    2Yunnan Key Laboratory of Plateau Wetland Conservation, Restoration and Ecological Services, Kunming 650224, China;
    3Napahai Provincial Nature Reserve Management and Protection Bureau, Diqing 674400, Yunnan, China;
    4Institute of Highland Forestry Science, Chinese Academy of Forestry, Kunming 650233, China;
    5Forest Seed and Seedling Station of Yunnan Province, Kunming 650215, China
  • Received:2023-02-16 Accepted:2023-04-12 Online:2023-06-15 Published:2023-12-15

Abstract: To explore the responses of soil microorganisms to short-term nitrogen deposition in alpine meadow, we set three treatments of low nitrogen (5 g N·m-2·a-1), medium nitrogen (10 g N·m-2·a-1), and high nitrogen (15 g N·m-2·a-1) addition to investigate the effects of nitrogen-deposition induced alterations in plant diversity and soil physicochemical properties on microbial biomass carbon (MBC) and nitrogen (MBN) in a typical alpine meadow community of Carex nubigena in Napahai. The results showed that nitrogen addition significantly increased soil MBC, MBN, and their quotients, with the increases of MBC being as high as 139.3% under medium nitrogen treatment. Both MBC and MBN showed significant decreases along the soil layer, with a reduction of 24.1% to 75.1%. Nitrogen addition significantly increased aboveground biomass and reduced Shannon and Simpson indices by 6.6%-65.4%. Nitrogen addition significantly decreased soil pH, increased the contents of organic matter, total nitrogen, ammonium nitrogen and nitrate nitrogen, with the highest reduction (7.0%-511.1%) being observed in medium nitrogen treatment. Soil pH increased while other physical and chemical indicators significantly decreased with the increases of soil layer, with a variation range of 19.5%-91.2%. Results of structural equation model showed that microbial biomass was significantly positively correlated with ammonium nitrogen, nitrate nitrogen and organic matter, but negatively correlated with pH and Shannon index. The interaction of plant and soil physicochemical properties explained 55%-77% of the variations in MBC, MBN and their quotient. Soil physicochemical properties had the highest effect value (0.56-0.95) on MBC, MBN and their quotients, followed by plant diversity and aboveground biomass. Therefore, nitrogen deposition increased soil MBC and MBN and their quotient, primarily through improving soil nutrient availability and plant aboveground biomass, whereas MBC and MBN and their quotient were suppressed by high-level nitrogen deposition due to soil acidification and plant diversity losses.

Key words: Napahai Plateau, alpine meadow, N deposition, microbial biomass carbon, microbicl biomass nitrogen, physical and chemical property