STOTEN：Mycorrhizal association controls soil carbon-degrading enzyme activities and soil carbon dynamics under nitrogen addition

Excessive nitrogen (N) deposition from human activities has continuously increased over the past decades, with strongly affects soil carbon (C) dynamics of terrestrial ecosystems. Soil microorganisms play a key role in regulating C dynamics under N deposition, while the complex underlying mechanism limits the inclusion of microbial mechanisms in global C cycle models. Soil C-degrading extracellular enzyme activities (C-EEAs) likely provide novel perspectives to track changes in microbially mediated soil C dynamics, however the response of C-EEAs to N deposition and the underly mechanisms remain unclear.

Our global analyses addressed the importance of mycorrhizal associations in predicting C-EEAs and soil C storage under N deposition (Figure 1). Specifically, N addition significantly stimulated cellulase activity, suppressed ligninase activity and enhanced soil C storage in ecosystems dominated by ectomycorrhizal plants. In contrast, C-EEAs and soil C storage were insensitive to N addition in ecosystems dominated by arbuscular mycorrhizal plants. These contrast results can be explained by the specific N-acquisition strategy of ECM plants and AM plants. These findings indicate the underestimation of soil C storage under N deposition in ecosystems dominated by ectomycorrhizal plants.

These results published in Science of the Total Environment (IF=8.2), entitled “Mycorrhizal association controls soil carbon-degrading enzyme activities and soil carbon dynamics under nitrogen addition: A systematic review”. Yuanliu Hu, a fellow postdoctoral at the South China Botanical Garden of the Chinese Academy of Sciences, is the first author of the paper. The corresponding authors are Qi Deng, a professor at the South China Botanical Garden, Chinese Academy of Sciences, and Ji Chen, a professor at the Institute of Earth Environment, Chinese Academy of Sciences. (Paper Link：https://doi.org/10.1016/j.scitotenv.2024.175008)

Figure 1.  Mechanisms for mycorrhizal controls of N addition impacts on soil carbon-degrading enzyme activities and soil carbon dynamics