Limited dependence on soil nitrogen fixation as subtropical forests develop

Ruoxian Fu; Chaoyang Cao; Li Liu; Hongguang Zhu; Saadat Malghani; Yuanchun Yu; Yangwenke Liao; Manuel Delgado-Baquerizo; Xiaogang Li

doi:10.1016/j.micres.2024.127757

Limited dependence on soil nitrogen fixation as subtropical forests develop

Microbiol Res. 2024 May 11:285:127757. doi: 10.1016/j.micres.2024.127757. Online ahead of print.

Authors

Ruoxian Fu¹, Chaoyang Cao¹, Li Liu¹, Hongguang Zhu¹, Saadat Malghani², Yuanchun Yu¹, Yangwenke Liao¹, Manuel Delgado-Baquerizo³, Xiaogang Li⁴

Affiliations

¹ State Key Laboratory of Tree Genetics and Breeding, Nanjing Forestry University, Nanjing 210037, China; College of Ecology and Environment, Nanjing Forestry University, Nanjing 210037, China.
² Department of Plant and Environmental Sciences, University of Copenhagen, Copenhagen 1017, Denmark.
³ Laboratorio de Biodiversidad y Funcionamiento Ecosistémico, Instituto de Recursos Naturales y Agrobiología de Sevilla (IRNAS), CSIC, Sevilla, Spain.
⁴ State Key Laboratory of Tree Genetics and Breeding, Nanjing Forestry University, Nanjing 210037, China; College of Ecology and Environment, Nanjing Forestry University, Nanjing 210037, China. Electronic address: xgli@njfu.edu.cn.

PMID: 38759379
DOI: 10.1016/j.micres.2024.127757

Abstract

Soil nitrogen (N) fixation, driven by microbial reactions, is critical to support the entrance of nitrogen in nutrient poor and pioneer ecosystems. However, how and why N fixation and soil diazotrophs evolve as forests develop remain poorly understood. Here, we used a 60-year forest rewilding chronosequence and found that soil N fixation activity gradually decreased with increasing forest age, experiencing dramatic drops of 64.8% in intermediate stages and 93.0% in the oldest forests. Further analyses revealed loses in diazotrophic diversity and a significant reduction in the abundance of important diazotrophs (e.g., Desulfovibrio and Pseudomonas) as forest develops. This reduction in N fixation, and associated shifts in soil microbes, was driven by acidification and increases in N content during forest succession. Our results provide new insights on the life history of one of the most important groups of soil organisms in terrestrial ecosystems, with consequences for understanding the buildup of nutrients as forest soil develops.

Keywords: Diazotroph; Edaphic factor; Forest development; Soil nitrogen fixation.