Effects of Nitrogen Addition on Soil Carbon-Fixing Microbial Diversity on Different Slopes in a Degraded Alpine Meadow

作者：Chengyi Li, Xilai Li, Yan Shi, Yuanwu Yang, Honglin Li · 发表于：Frontiers in Plant Science · 年份：2022 · DOI：10.3389/fpls.2022.921278 · 被引用次数：22 · 研究领域：Peatlands and Wetlands Ecology、Soil Carbon and Nitrogen Dynamics、Coastal wetland ecosystem dynamics

Autotrophic carbon-fixing bacteria are a major driver of carbon sequestration and elemental cycling in grassland ecosystems. The characteristics of the response of carbon-fixing bacterial communities to nitrogen (N) addition in degraded alpine meadows are unclear. In this study, it was investigated that the effects of N addition in three levels [they are low (LN), middle (MN), and high (HN) with N supplement of 2, 5, and 10 g N⋅m –2 ⋅a –1 , respectively] on soil carbon-fixing bacteria on different slopes in a degraded alpine meadow in the Yellow River on the Qinghai–Tibet Plateau. The results showed that there were significant differences in the abundance of some low abundance genera of carbon-fixing bacteria on the same slope ( P < 0.05), but the differences in the abundance of various phyla and dominant genera were not significant. MN on gentle slopes significantly reduced the Chao1 index and observed species ( P < 0.05), whereas N addition on steep slopes had no significant effect on the diversity. The abundance of the Cyanobacteria phylum and 28 genera of identified carbon-fixing bacteria differed significantly between slopes ( P < 0.05), and observed species of carbon-fixing bacteria were significantly higher on steep slopes than on gentle slopes ( P < 0.05). Factors affecting the carbon-fixing bacteria community structure include slope, N addition, ammoniacal nitrogen (N-NH 4 + ), microbial biomass carbon (MBC), soil water content (SWC), pH, ...