Suppressed N fixation and diazotrophs after four decades of fertilization

作者：Kunkun Fan, Manuel Delgado‐Baquerizo, Xisheng Guo, Daozhong Wang, Yanying Wu, Mo Zhu, Wei Yu, Huaiying Yao, Yong‐Guan Zhu, Haiyan Chu · 发表于：Microbiome · 年份：2019 · DOI：10.1186/s40168-019-0757-8 · 被引用次数：395 · 研究领域：Soil Carbon and Nitrogen Dynamics、Microbial Community Ecology and Physiology、Polar Research and Ecology

BACKGROUND: N fixation is one of the most important microbially driven ecosystem processes on Earth, allowing N to enter the soil from the atmosphere, and regulating plant productivity. A question that remains to be answered is whether such a fundamental process would still be that important in an over-fertilized world, as the long-term effects of fertilization on N fixation and associated diazotrophic communities remain to be tested. Here, we used a 35-year fertilization experiment, and investigated the changes in N fixation rates and the diazotrophic community in response to long-term inorganic and organic fertilization. RESULTS: It was found that N fixation was drastically reduced (dropped by 50%) after almost four decades of fertilization. Our results further indicated that functionality losses were associated with reductions in the relative abundance of keystone and phylogenetically clustered N fixers such as Geobacter spp. CONCLUSIONS: Our work suggests that long-term fertilization might have selected against N fixation and specific groups of N fixers. Our study provides solid evidence that N fixation and certain groups of diazotrophic taxa will be largely suppressed in a more and more fertilized world, with implications for soil biodiversity and ecosystem functions.