Mitigating methane emission from paddy soil with rice-straw biochar amendment under projected climate change

Area of Science:

• Agricultural Science
• Environmental Science
• Soil Science

Background:

• Climate change, driven by elevated global temperatures and increased atmospheric carbon dioxide (CO2), significantly impacts rice cropping systems.
• Rice cultivation is a major source of methane (CH4), a potent greenhouse gas.
• Previous studies indicate biochar can reduce CH4 emissions from paddy soil under ambient conditions.

Purpose of the Study:

• To evaluate the efficacy of rice straw-derived biochar in mitigating CH4 emissions from paddy soil under simulated future climate conditions (elevated temperature and CO2).

Main Methods:

• Field experiment applying rice straw-derived biochar to paddy soil.
• Measurement of CH4 emissions under ambient and elevated temperature and CO2 conditions.
• Analysis of microbial community structure and function, including methanogen activity and methanotroph abundance (pmoA gene).

Main Results:

• Biochar application reduced CH4 emissions under ambient conditions.
• A significant reduction of 39.5% in CH4 emissions was observed under simultaneously elevated temperature and CO2.
• Reduced CH4 release was linked to decreased methanogen activity and increased CH4 oxidation by methanotrophs.

Conclusions:

• Rice straw-derived biochar is a viable strategy for mitigating CH4 emissions from paddy soils, even under projected future climate change scenarios.
• Biochar amendment contributes to greenhouse gas control in agricultural systems facing climate change.
• The study underscores the importance of biochar in sustainable rice production and climate change adaptation.