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Huang R, Li Z, Xiao Y, Liu J, Jiang T, Deng O, Tang X, Wu Y, Tao Q, Li Q, Luo Y, Gao X, Wang C, Li B. Composition of DOM along the depth gradients in the paddy field treated with crop straw for 10 years. JOURNAL OF ENVIRONMENTAL MANAGEMENT 2024; 353:120084. [PMID: 38281421 DOI: 10.1016/j.jenvman.2024.120084] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/14/2023] [Revised: 01/06/2024] [Accepted: 01/07/2024] [Indexed: 01/30/2024]
Abstract
Crop straw return is a widely used agricultural management practice. The addition of crop straw significantly alters the pool of dissolved organic matter (DOM) in agricultural soils and plays a pivotal role in the global carbon (C) cycle, which is sensitive to climate change. The DOM concentration and composition at different soil depths could regulate the turnover and further storage of organic C in terrestrial systems. However, it is still unclear how crop straw return influences the change in DOM composition in rice paddy soils. Therefore, a field experiment was conducted in which paddy soil was amended with crop straw for 10 years. Two crop straw-addition treatments [NPK with 50% crop straw (NPK+1/2S) and NPK with 100% crop straw (NPK + S)], a conventional mineral fertilization control (NPK) and a non-fertilized control were included. Topsoil (0-20 cm) and subsoil (20-40 cm) samples were collected to investigate the soil DOM concentration and compositional structure of the profile. Soil nutrients, iron (Fe) fraction, microbial biomass carbon (MBC), and concentration and optical properties (UV-Vis and fluorescence spectra) of soil DOM were determined. Here, we found that the DOM in the topsoil was more humified than that in the subsoil. The addition of crop straw further decreased the humidification degree of DOM in the subsoil. In crop straw-amended topsoil, microbial decomposition controlled the composition of DOM and induced the formation of aromatic DOM. In the straw-treated subsoil, selective adsorption by poorly crystalline Fe(oxyhydr)oxides and microbial decomposition controlled the composition of DOM. In particular, the formation of protein-like compounds could have played a significant role in the microbial degradation of DOM in the subsoil. Overall, this work conducted a case study within long-term agricultural management to understand the changes in DOM composition along the soil profile, which would be further helpful for evaluating C cycling in agricultural ecosystems.
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Affiliation(s)
- Rong Huang
- College of Resources, Sichuan Agricultural University, Chengdu, 611130, China; Interdisciplinary Research Centre for Agriculture Green Development in Yangtze River Basin, Department of Environmental Sciences and Engineering, College of Resources and Environment, Southwest University, Chongqing, 400716, China; Key Laboratory of Investigation and Monitoring, Protection and Utilization for Cultivated Land Resources, Ministry of Natural Resources, Chengdu, 611130, China
| | - Zheng Li
- College of Resources, Sichuan Agricultural University, Chengdu, 611130, China
| | - Yi Xiao
- College of Resources, Sichuan Agricultural University, Chengdu, 611130, China
| | - Jiang Liu
- College of Resources, Sichuan Agricultural University, Chengdu, 611130, China; State Key Laboratory of Environmental Geochemistry, Institute of Geochemistry, Chinese Academy of Sciences, Guiyang, 550081, China; Interdisciplinary Research Centre for Agriculture Green Development in Yangtze River Basin, Department of Environmental Sciences and Engineering, College of Resources and Environment, Southwest University, Chongqing, 400716, China
| | - Tao Jiang
- Interdisciplinary Research Centre for Agriculture Green Development in Yangtze River Basin, Department of Environmental Sciences and Engineering, College of Resources and Environment, Southwest University, Chongqing, 400716, China.
| | - Ouping Deng
- College of Resources, Sichuan Agricultural University, Chengdu, 611130, China
| | - Xiaoyang Tang
- College of Resources, Sichuan Agricultural University, Chengdu, 611130, China
| | - Yingjie Wu
- College of Resources, Sichuan Agricultural University, Chengdu, 611130, China
| | - Qi Tao
- College of Resources, Sichuan Agricultural University, Chengdu, 611130, China
| | - Qiquan Li
- College of Resources, Sichuan Agricultural University, Chengdu, 611130, China
| | - Youlin Luo
- College of Resources, Sichuan Agricultural University, Chengdu, 611130, China
| | - Xuesong Gao
- College of Resources, Sichuan Agricultural University, Chengdu, 611130, China; Key Laboratory of Investigation and Monitoring, Protection and Utilization for Cultivated Land Resources, Ministry of Natural Resources, Chengdu, 611130, China
| | - Changquan Wang
- College of Resources, Sichuan Agricultural University, Chengdu, 611130, China
| | - Bing Li
- College of Resources, Sichuan Agricultural University, Chengdu, 611130, China.
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