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| 中国南方典型稻作梯田土壤有机碳积累及其来源表征 |
| Characterization of organic carbon pool and the source of paddy soil from typical rice terraces across southern China |
| 投稿时间：2023-12-22 |
| DOI：10.13254/j.jare.2023.0827 |
| 中文关键词: 稻作梯田，土壤有机碳，木质素，氨基糖，有机碳固定，来源解析 |
| 英文关键词: paddy terrace, soil organic carbon, lignin, amino sugar, carbon sequestration, source discrimination |
| 基金项目:国家自然科学基金项目（42077082） |
| 作者 | 单位 | E-mail | | 韩玥 | 南京农业大学农业资源与生态环境研究所, 南京 210095
南京农业大学资源与环境科学学院, 南京 210095 | | | 赵正 | 南京农业大学农业资源与生态环境研究所, 南京 210095
南京农业大学资源与环境科学学院, 南京 210095 | | | 田静 | 南京农业大学农业资源与生态环境研究所, 南京 210095
南京农业大学资源与环境科学学院, 南京 210095 | | | 龙国刚 | 南京农业大学农业资源与生态环境研究所, 南京 210095 | | | 龚婧雯 | 南京农业大学农业资源与生态环境研究所, 南京 210095
南京农业大学资源与环境科学学院, 南京 210095 | | | 王廷好 | 南京农业大学农业资源与生态环境研究所, 南京 210095
南京农业大学资源与环境科学学院, 南京 210095 | | | 沈易 | 南京农业大学农业资源与生态环境研究所, 南京 210095
南京农业大学资源与环境科学学院, 南京 210095 | | | 毛子仪 | 南京农业大学农业资源与生态环境研究所, 南京 210095
南京农业大学资源与环境科学学院, 南京 210095 | | | 李恋卿 | 南京农业大学农业资源与生态环境研究所, 南京 210095
南京农业大学资源与环境科学学院, 南京 210095 | | | 张旭辉 | 南京农业大学农业资源与生态环境研究所, 南京 210095
南京农业大学资源与环境科学学院, 南京 210095 | xuhuizhang@njau.edu.cn | | 潘根兴 | 南京农业大学农业资源与生态环境研究所, 南京 210095
南京农业大学资源与环境科学学院, 南京 210095 | pangenxing@aliyun.com |
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| 中文摘要: |
| 研究长期耕作管理下土壤有机碳（SOC）固持能力及其积累机制是当前农业可持续发展基础研究的前沿。我国南方山区稻作梯田是国际社会公认的全球重要农业遗产，本研究旨在剖析其千年可持续水稻生产下有机碳的积累特征，探索基于自然的农田固碳技术途径。以我国南方山区5处典型稻作梯田系统为研究对象，采集0~20 cm（表土）、20~40 cm（心土）和40~60 cm（底土）深度土壤样品，分析土壤有机碳形态与分布特征，同时采用生物标志物分子提取和GC-MS鉴定技术，分析木质素及氨基糖含量变化来解析有机碳的不同来源。结果表明：供试5处梯田表土有机碳积累水平差异极大，发育于沉积岩的四川新山梯田和高坎梯田黏粒含量高达40%，各层有机碳含量在15.58~47.78 g·kg-1范围内，而发育于花岗岩的江西上堡梯田、浙江云和梯田和湖南紫鹊界梯田的砂粒含量高达40%~66%，各层土壤有机碳含量在7.41~30.86 g·kg-1范围内。在深度上，土壤有机碳分布存在分层性：表土有机碳含量（17.98~47.78 g·kg-1）大幅高于心土、底土；相较于表土，心土层SOC含量降低24.8%~62.2%，底土层SOC含量则降低47.1%~76.0%。表土具有较高的木质素含量及较低的氧化程度，较高的MBC（微生物生物量碳）/SOC值、POC（颗粒态有机碳）/MAOC（矿物结合态有机碳）值及较低的DOC（溶解性有机碳）/SOC值；相反，心土、底土有机碳含量较为匮缺（除高坎梯田外，均低于20 g·kg-1），MAOC占比较高。所有样品的总有机碳含量与木质素酚含量间呈极显著的正相关关系（R2=0.909，P<0.01）。研究表明，植物源有机碳因颗粒态物理保护作用而在黏质水稻土中积累，这是千年稻作梯田有机碳稳定积聚的主要机制。 |
| 英文摘要: |
| The capacity for soil organic carbon（SOC）sequestration and the underlying mechanisms governing sequestration under long term agro-management is the frontier of basic research of sustainable agriculture. Rice terraces in the mountainous areas of southern China have been recognized as a globally important agricultural heritage. The purpose of this study was to analyze SOC accumulation under the millennium-scale rice cultivation and to explore nature-based solutions for SOC sequestration in rice agriculture. In this study, a number of typical rice terrace systems were selected from mountainous areas in southern China. Undisturbed bulk samples were collected with a soil core sampler sequentially at depths of 0 -20 cm（topsoil）, 20-40 cm（subsoil）and 40-60 cm（deep soil）below surface from these terrace paddies. SOC content and pools of all samples were analyzed using a wet digestion protocol. Subsequently, abundances of lignin and amino sugars were determined using biomarker molecule extraction and GC-MS detection to interpret potential sources. There were wide variations of topsoil SOC levels among the five rice terrace systems. SOC content of different layers ranged in-between 15.58-47.78 g·kg-1 for Xinshan and Gaokan terraces in Sichuan, developed on sedimentary rocks and rich in clay minerals（>40%）. However, for Shangbao terrace in Jiangxi, Yunhe terrace of Zhejiang and Ziquejie terrace of Hunan developed on granite and soil rich in sand grains（40%-66%）, SOC content of different layers ranged in-between 7.41-30.86 g·kg-1. The accumulation of SOC was highly stratified, with significantly higher values in topsoil（ranging between 17.98-47.78 g·kg-1）than in deep soil. Relative to topsoil, SOC decreased by 24.8%-62.2% in subsoil and by 47.1%-76.0% in deep soil. The topsoil was higher in lignin content and lower in lignin oxidation, and higher in the ratio of MBC（microbial biomass C）/SOC and of POC（particulate OC）/MAOC（mineral bound OC）, and lower in the ratio of DOC（dissolvable OC）/ SOC, than subsoil and deep soil. In contrast, the low SOC in subsoil and deep soil（all lower than 20 g·kg-1 except Gaokan terrace）was dominant in MAOC. For all samples, SOC content was significantly and strongly correlated to soil lignin content（R2=0.908 9, P<0.01）. Overall, physical protection of plant-derived OC mimicked the high OC accumulation in clayey rice terraces under millennial paddy management. |
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