文献类型：期刊文献

英文题名：Depression of soil nitrogen fixation by drying soil in a degraded alpine peatland

作者：Zhang, Xiaodong[1,2] Jia, Xin[3] Wu, Haidong[1,2] Li, Jing[1] Yan, Liang[1,2] Wang, Jinzhi[1,2] Li, Yong[1,2] Kang, Xiaoming[1,2]

第一作者：Zhang, Xiaodong;张骁栋

通信作者：Kang, XM[1]

机构：[1]Chinese Acad Forestry, Inst Wetland Res, Beijing Key Lab Wetland Serv & Restorat, Beijing 100091, Peoples R China;[2]Sichuan Zoige Wetland Ecosyst Res Stn, Zoige 624500, Tibetan Autonom, Peoples R China;[3]Beijing Forestry Univ, Yanchi Res Stn, Sch Soil & Water Conservat, Beijing 100083, Peoples R China

年份：2020

卷号：747

外文期刊名：SCIENCE OF THE TOTAL ENVIRONMENT

收录：;EI(收录号：20203209017689);Scopus(收录号：2-s2.0-85088923581);WOS:【SCI-EXPANDED(收录号:WOS:000579386300020)】；

基金：Thisworkwas supported by the Fundamental Research Funds of CAF (CAFYBB2017SY042), the National Key Research and Development Program of China (2016YFC0501804), and the National Natural Science Foundation of China (31770511, 41701113, 41877421).

语种：英文

外文关键词：Zoige Plateau; Diazotroph; nifH gene; Soil moisture; Meadow

摘要：Soil biological nitrogen fixation (BNF) represents a major pathway through which nitrogen enters pristine peatlands. Many peatlands have been undergoing human-induced changes in environmental factors, while environmental changes dramatically affect the community composition and activity of nitrogen-fixing prokaryotes (i.e., diazotrophs). However, the impact of peatland degradation on soil BNF remains unclear. By carrying out a field campaign, we examined how soil BNF varies along a natural gradient from pristine marshes to moderately-degraded meadows and sandy meadows on the Zoige Plateau. Plant and topsoil samples from four pristine marshes, three moderately-degraded meadows, and three sandy meadows were collected to determine the potential rate of nitrogen fixation (R-Nfix), abundance of the nifH gene, diazotrophic community composition, and soil and plant characteristics. Our results showed that topsoil R-Nfix varied in the range 0.018-3.00 mu mol N g d.w.(-1) day(-1) (i.e. 21.74-1632.37 mg N m(-2) day(-1)) across the ten sites, being lowest in sandy meadows and highest in pristine marshes. Topsoil R-Nfix and diazotrophic abundance were positively correlated with soil water content, sedge cover, plant biomass, soil organic carbon content, and total nitrogen and phosphorus contents. Soil water content, which affected most plant and soil characteristics, had dominant influences on the abundance and community structure of diazotrophs. The R-Nfix was closely correlated with the abundance of dominant diazotroph groups. The community composition of diazotrophs differed markedly among sites of different degradation levels. Proteobacteria was the most abundant diazotrophic phylum across the ten sites. Heterotrophic diazotrophs acted as the major contributor to BNF, especially in pristine marshes and moderately-degraded meadows. We conclude that soil water content was the main factor driving the depressed soil BNF during peatland degradation in Zoige, due to soil water effects on plant cover and biomass, soil organic carbon and total phosphorus, and the abundance and community structure of diazotrophs. (C) 2020 Elsevier B.V. All rights reserved.