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

作　　者：韩玥 赵正 田静 龙国刚 龚婧雯 王廷好 沈易 毛子仪 李恋卿[1,2] 张旭辉[1,2] 潘根兴[1,2] HAN Yue;ZHAO Zheng;TIAN Jing;LONG Guogang;GONG Jingwen;WANG Tinghao;SHEN Yi;MAO Ziyi;LI Lianqing;ZHANG Xuhui;PAN Genxing(Institute of Resource,Ecosystem and Environment of Agriculture,Nanjing Agricultural University,Nanjing 210095,China;College of Resources and Environmental Sciences,Nanjing Agricultural University,Nanjing 210095,China)

机构地区：[1]南京农业大学农业资源与生态环境研究所,南京210095 [2]南京农业大学资源与环境科学学院,南京210095

出　　处：《农业资源与环境学报》2025年第1期139-148,共10页Journal of Agricultural Resources and Environment

基　　金：国家自然科学基金项目(42077082)。

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(R^(2)=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。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

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 

分 类 号：S153.6[农业科学—土壤学]