Linear relationship between CH4 fluxes and atmospheric CO2 concentration levels controlled by rice biomass and soil methanogenic communities.

Autor: Wang, Yuanyuan, Hu, Zhenghua, He, Shuqi, Jing, Qiang, Shen, Lidong, Liu, Chao, Wu, Zhurong, Huang, Wei, Lu, Guihua, Cao, Rui, Zheng, Kezhi, Dong, Ning, Jiang, Lu, Ye, Jiayao, Rong, Anqi, Xia, Xuqin, Sun, Ye
Zdroj: Nutrient Cycling in Agroecosystems; Nov2023, Vol. 127 Issue 2, p247-263, 17p
Abstrakt: The contribution of CH4 emissions from paddy soils to greenhouse gas emissions is key in the evaluation of future climate change scenarios. Most studies in this field have investigated the effects of elevated CO2 concentrations (e[CO2]s) on CH4 fluxes and methanogenic communities in paddy soils under constant CO2 concentrations ([CO2]s). However, atmospheric [CO2] is gradually increasing and the relationship between future climate change and CH4 emissions from paddy fields is poorly understood. This study explored the responses of CH4 fluxes and methanogenic communities in paddy soils to different e[CO2]s using open-top chambers. The rice biomass, CH4 fluxes, methane production potential, and methanogenic characteristics were analyzed under CK (ambient [CO2]), C1 (e[CO2] by 120 µmol mol–1), and C2 (e[CO2] by 200 µmol mol–1) treatments. The results indicated that the C1 and C2 treatments insignificantly increased the CH4 flux in paddy fields. However, the C1 treatment significantly increased the CH4 flux/biomass at the elongation stage, while the C2 treatment significantly increased the CH4 flux/biomass at all of the growth stages. The C1 and C2 treatments had a positive effect on both methane production potential and methanogenic abundance at all of the growth stages, but this effect was not always significant. In addition, the C1 and C2 treatments significantly altered the methanogenic community structure at the elongation stage. Notably, there was a significant linear relationship between the CH4 flux/biomass and [CO2] at all of the growth stages; between the methane production potential and [CO2] at the tillering, elongation, and milk-ripening stages; and between the mcrA gene abundance and [CO2] at the milk-ripening stage. A linear model based on rice biomass, methane production potential, and soil DOC concentration explained 72.7% of the variation in the CH4 fluxes. Overall, the linear relationship between CH4 fluxes and atmospheric [CO2] levels was controlled by the rice biomass, soil carbon substrate, and methanogenic communities. [ABSTRACT FROM AUTHOR]
Databáze: Complementary Index
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