Effects of warming on rice production and metabolism process associated with greenhouse gas emissions

Evaluating the impact of global warming on rice production and greenhouse gas (GHG) emissions is critical for ensuring food security and mitigating the consequences of climate change. Nonetheless, the impacts of warming on crop production, GHG emissions, and microbial mechanisms in the single-cropping rice systems remain unclear. Here, a two-year field experiment was conducted to explore the effects of warming (increased by 2.7-3.0 °C on average) in the rice growing season on crop production and functional microorganisms associated with GHG emissions. Results showed that warming resulted in significant reduction (p < 0.01) in the aboveground biomass and grain yield as well as in grain weight, the number of spikelets per panicle, and the seed-setting rate. However, it caused a significant increase (p < 0.01) in the number of panicles by 15.6 % and 34.9 %, respectively. Furthermore, warming significantly increased (p < 0.01) seasonal methane (CH₄) emissions but reduced nitrous oxide (N₂O) emissions, particularly in 2022.The relative abundance of genes associated with CH₄ metabolism and nitrogen metabolism was increased by 40.7 % and 32.7 %, respectively, in response to warming. Moreover, warming had a positive impact on the abundance of genes related to CH₄ production and oxidation processes but did not affect the denitrification processes associated with N₂O production. These results showed that warming decreased rice yield and biomass in the single cropping rice system but increased CH₄ emissions and global warming potential. Taken together, to address the increasing food demand of a growing population and mitigate the impacts of global warming, it is imperative to duce GHG emissions and enhance crop yields.