Pedosphere 35(4): 603--616, 2025
ISSN 1002-0160/CN 32-1315/P
©2025 Soil Science Society of China
Published by Elsevier B.V. and Science Press
| Microbiological mechanisms of lignin- and humus-derived small molecule addition promoting straw conversion into soil organic matter in a sodic soil |
Jingwang LI1,2, Lin CHEN1, Fengxia YUE3, Congzhi ZHANG1, Donghao MA1, Guixiang ZHOU1, Jiangli WANG3, Changdong HAN4, Biao FENG1,2, Jiabao ZHANG1,2 |
1 Fengqiu Experimental Station of National Ecosystem Research Network of China, State Key Laboratory of Soil and Sustainable Agriculture, Institute of Soil Science, Chinese Academy of Sciences, Nanjing 211135 (China)
2 University of Chinese Academy of Sciences, Beijing 100049 (China)
3 State Key Laboratory of Pulp and Paper Engineering, South China University of Technology, Guangzhou 510640 (China)
4 College of Land and Environment, Shenyang Agricultural University, Shenyang 110866 (China) |
| ABSTRACT |
| Straw return is the main practice used to increase soil organic matter (SOM) in agricultural ecosystems. To increase the efficiency of straw conversion to SOM, a large number of microbial inoculants have been developed. However, their effects are poor because of the complex water and temperature conditions, especially under sodic conditions. Small molecules can rapidly shift soil microbial communities and improve their ability to transform exogenous organic matter into SOM, providing a new direction for promoting high-efficiency straw conversion into SOM. In this study, we conducted a 13C-labeled straw degradation experiment using small molecules derived from lignin (LSMs) and humus (HSMs) as activators, investigating their effects on the microbial communities and formation of newly formed mineral-associated (13C-MAOM) and particulate (13C-POM) organic matter from 13C-labeled straw in both sodic and non-sodic soils. The 13C-labeled straw was mainly converted into 13C-MAOM, accounting for 73.97%-92.67% of the newly formed SOM. Biopolymer-derived small molecules decreased the exchangeable sodium percentage (ESP), but increased contents of 13C-MAOM and 13C-POM by shifting microbial communities, strengthening microbial cross-trophic interactions, enhancing enzyme activities, and increasing microbial residues in both soils. Addition of HSMs had greater impacts on 13C-MAOM formation than LSM addition. The 13C-MAOM and 13C-POM formation negatively correlated with ESP, but positively correlated with microbial cross-trophic interactions and enzyme activities in both soils. Our results suggest that biopolymer-derived small molecules promote 13C-MAOM and 13C-POM formation associated with microbial cross-trophic interactions between protistan predators and primary decomposers. Our study provides scientific support for future attempts to stimulate microbial cross-trophic interactions for boosting SOM accumulation under stressed conditions. |
| Key Words: biopolymer-derived small molecule,microbial community,mineral-associated organic matter,particulate organic matter,protist,trophic interaction |
| Citation: Li J W, Chen L, Yue F X, Zhang C Z, Ma D H, Zhou G X, Wang J L, Han C D, Feng B, Zhang J B. 2025. Microbiological mechanisms of ligninand humus-derived small molecule addition promoting straw conversion into soil organic matter in a sodic soil. Pedosphere. 35(4): 603-616. |
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