Tang, Han; Hu, Jiajun; Liu, Yundong; Li, Bu; Wang, Jia; Tong, Wang Kai; Yue, Mei Ru; Zou, Jia Jie; Gao, Min-tian; Zhang, Saiwei; Liu, Nan; Li, Jixiang

JOURNAL OF ENVIRONMENTAL CHEMICAL ENGINEERING

2025, 5,

Tang, Han; Hu, Jiajun; Liu, Yundong; Li, Bu; Wang, Jia; Tong, Wang Kai; Yue, Mei Ru; Zou, Jia Jie; Gao, Min-tian; Zhang, Saiwei; Liu, Nan; Li, Jixiang

Soil carbon pool, as the largest terrestrial carbon pool, is crucial for the global carbon cycle. In this study, autotrophic microbial agents and low-release biochar (AM&BC-SR), as a combined soil amendment, were attempted to boost soil carbon sequestration. After one year, AM&BC-SR's soil organic carbon was 33 % higher than the initial and 78 % above Blank, achieving a net carbon fixation of 4.1 g/kg. Compared to conventional biochar, low-release biochar was more stable and controllable due to its resistance to soil microbial degradation, and the autotrophic microbial agents strengthened this property. Moreover, their synergistic effect was manifested in the soil physical and chemical properties and soil carbon metabolism. AM&BC-SR significantly promoted the Calvin-Benson cycle, the most widely distributed microbial carbon fixation pathway in nature, with the abundance of key enzyme genes being 35 similar to 120 % higher than Blank. In soil heterotrophic metabolism, AM&BC-SR also promoted the glycolysis pathway. These led to a synergistic effect among biochar, autotrophic microbial agents, and soil indigenous heterotrophic microorganisms. This functional system enabled AM&BC-SR to effectively increase soil organic carbon while keeping the rise in soil respiration at a low level. AM&BC-SR, as a green fertilizer and a novel carbon-neutral technology, can play an unprecedented role in soil improvement.