Nitrogen and water availability control plant carbon storage with warming

作者：Zhou, Guiyao; Terrer, Cesar; Huang, An; Hungate, Bruce A.; van Gestel, Natasja; Zhou, Xuhui^*; van Groenigen, Kees Jan^*

来源：Science of the Total Environment, 2022, 851: 158243.

DOI：10.1016/j.scitotenv.2022.158243

• C-climate feedback
• Climate warming
• Nitrogen availability
• Meta-analysis
• Mycorrhizal association
• Plant biomass

Plants may slow global warming through enhanced growth, because increased levels of photosynthesis stimulate the land carbon (C) sink. However, how climate warming affects plant C storage globally and key drivers determining the response of plant C storage to climate warming remains unclear, causing uncertainty in climate projections. We per-formed a comprehensive meta-analysis, compiling 393 observations from 99 warming studies to examine the global patterns of plant C storage responses to climate warming and explore the key drivers. Warming significantly increased total biomass (+8.4 %), aboveground biomass (+12.6 %) and belowground biomass (+10.1 %). The effect of exper-imental warming on plant biomass was best explained by the availability of soil nitrogen (N) and water. Across the en-tire dataset, warming-induced changes in total, aboveground and belowground biomass all positively correlated with soil C:N ratio, an indicator of soil N availability. In addition, warming stimulated plant biomass more strongly in humid than in dry ecosystems, and warming tended to decrease root:shoot ratios at high soil C:N ratios. Together, these results suggest dual controls of warming effects on plant C storage; warming increases plant growth in ecosystems where N is limiting plant growth, but it reduces plant growth where water availability is limiting plant growth.