Pedosphere (2): 497--510, 2026
ISSN 1002-0160/CN 32-1315/P
©2026 Soil Science Society of China
Published by Elsevier B.V. and Science Press
| Artificial humic acid promotes carbon sequestration in the rice-soil system |
Zeyu ZHANG1,2, Yu QIAO1,2, Dongxing XIE1,2, Jicheng HAN1,2, Zhuqing LIU1,2, Ying ZHAO1,2 , Fan YANG1,2 |
1 International Cooperation Joint Laboratory of Health in Cold Region Black Soil Habitat of the Ministry of Education, Harbin 150030 (China)
2 School of Water Conservancy & Civil Engineering, Northeast Agricultural University, Harbin 150030 (China) |
| ABSTRACT |
| Artificial humic acid (AHA) is a new exogenous organic material with enormous carbon (C) sequestration potential. However, the effects of applying AHA under different irrigation regimes on C sequestration in the rice-soil system and the underlying mechanisms still need to be clarified. This study employed C isotope labeling technology to analyze the photosynthetic C sequestration capacity, C transport capacity of rice roots, and greenhouse gas emission flux in the rice-soil system under different irrigation regimes and AHA application conditions. The results showed that as the amount of AHA application increased, the leaf area and chlorophyll concentration gradually increased, and the ribulose-1,5-bisphosphate carboxylase/oxygenase (Rubisco) activity first increased and then decreased under two irrigation regimes (conventional flooding and alternate wetting and drying irrigation). In the alternate wetting and drying irrigation with 300 mg kg-1 AHA application treatment (DWI3), the photosynthetic C fixation was the highest, with the net photosynthetic rate increasing by 65.35% compared to the alternate wetting and drying irrigation without applying AHA treatment (DWI0). Meanwhile, the organic acid concentration in root exudates, biomass, length, surface area, and length density were also the highest in the DWI3 treatment. Besides, the content of 13C in soil was the highest in the DWI3 treatment, closely related to the strongest photosynthetic C fixation and root transport capacity, as well as the lowest greenhouse gas emission flux. Therefore, it is recommended to apply 300 mg kg-1AHA with alternate wetting and drying irrigation for C sequestration, water conservation, and sustainable agricultural development. |
| Key Words: alternate wetting and drying irrigation,C isotope labeling,chlorophyll fluorescence,conventional,flooding irrigation,isotope tracing technology,photosynthesis,root exudates |
| Citation: Zhang Z Y, Qiao Y, Xie D X, Han J C, Liu Z Q, Zhao Y, Yang F. 2026. Artificial humic acid promotes carbon sequestration in the rice-soil system. Pedosphere. 36(2): 497-510. |
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