摘要
温室气体氧化亚氮(N_(2)O)已成为全球关注的焦点,全球约60%的人为N_(2)O排放来自农业土壤.虽然已知微生物硝化和反硝化是土壤N_(2)O产生的主要过程,但N_(2)O产生的关键生物学机制以及其调控环境变量之间的相互作用仍然难以预测.本研究选取安徽省亳州市冬、夏两季农田垂向土壤(0~200 cm)为研究对象,通过乙炔抑制法、15N-18O同位素示踪技术分别测定了N_(2)O产生潜势及产生途径,并利用宏基因组测序技术分析不同N_(2)O产生途径中功能基因的丰度变化以解析农田土壤N_(2)O产生的微生物机理.结果显示,在空间尺度上,表层土壤(0~20 cm)是N_(2)O产生热区,其N_(2)O产生潜势最高,为(0.364±0.048)ng·g^(-1)·h^(-1).硝化和反硝化潜势均在表层土壤达到最高.在时间尺度上,冬季(15℃)是N_(2)O产生热时,冬季样品N_(2)O产生潜势显著高于夏季样品,分别为(0.198±0.007)和(0.057±0.009)ng·g^(-1)·h^(-1).总体而言,硝化过程是农田土壤N_(2)O产生的主要来源,其中,硝化细菌反硝化过程(ND)对N_(2)O产生的贡献率最高,为52%,而硝化细菌硝化过程(NN)和硝化反应偶联的反硝化过程(NCD)的贡献率分别为24%和0.统计分析表明,农田土壤N_(2)O产生、硝化及反硝化潜势与理化性质(MC、pH、TN)和功能基因相对丰度(hao、nirK、norB)存在显著相关性.本研究揭示了农田土壤中N_(2)O的产生机理及关键影响因素,并强调了冬季农田土壤中N_(2)O的产生不容忽视,这些结果对准确评估我国农业温室气体排放具有重要意义.
Nitrous oxide(N_(2)O)as a greenhouse gas has become the focus of global concern,and about 60%anthropogenic N_(2)O emissions come from agricultural soils.Despite microbial nitrification and denitrification are the main processes involved in soil N_(2)O production,the key biological mechanisms of N_(2)O production and their regulatory environmental factors remain difficult to predict.This study was conducted to analyze the microbial mechanism of N_(2)O production in the vertically distributed agricultural soils during winter and summer in Bozhou,Anhui Province,China.The potential and pathways of N_(2)O production were determined by acetylene inhibition and 15N-18O dual isotope tracing techniques.Furthermore,the abundance of functional genes in different N_(2)O production pathways was investigated by metagenomic sequencing technology.At the spatial scale,the results indicated that the surface soil(0~20 cm)was the hotspot of N_(2)O production with the highest N_(2)O production potential of(0.364±0.048)ng·g^(-1)·h^(-1).Both the nitrification and denitrification potentials reached the highest in the surface soil.At the time scale,winter(15℃)was the hotspot of N_(2)O production.The potential of winter N_(2)O production((0.198±0.007)ng·g^(-1)·h^(-1))was significantly higher than that in summer((0.057±0.009)ng·g^(-1)·h^(-1)).Generally,nitrification was the main process of N_(2)O production in agricultural soils.The contribution of nitrifier denitrification to N_(2)O production was 52%,and the contribution of nitrifier nitrification(NN)and nitrification coupled denitrification processes(NCD)were 24%and 0,respectively.The correlation analysis showed that N_(2)O production,nitrification and denitrification potential of agricultural soils were significantly correlated with physicochemical properties(MC,pH,TN)and relative abundance of functional genes(hao,nirK,norB).This study reveals the mechanism and influencing factors of N_(2)O production in agricultural soils,and emphasizes that N_(2)O production in winter cannnot be ignored.This study has important implications for the accurate assessment of agricultural greenhouse gas emissions in China.
作者
孙立博
王晓玲
王旭敏
姜丽萍
蒋佳益
王晓敏
祝贵兵
SUN Libo;WANG Xiaoling;WANG Xumin;JIANG Liping;JIANG Jiayi;WANG Xiaomin;ZHU Guibing(School of Municipal and Environmental Engineering,Jilin Jianzhu University,Changchun 130118;Key Laboratory of Drinking Water Science and Technology,Research Center for Eco-Environmental Sciences,Chinese Academy of Sciences,Beijing 100085)
出处
《环境科学学报》
CAS
CSCD
北大核心
2022年第10期441-451,共11页
Acta Scientiae Circumstantiae
基金
国家自然科学基金(No.91851204)
中国科学院生态环境研究中心生态环境卓越创新项目(No.RCEES-EEI-2019-02)
中国科学院青年创新促进会项目。
关键词
农田垂向土壤
氧化亚氮
季节
硝化
硝化细菌反硝化
功能基因相对丰度
vertical soil of agricultural soils
nitrous oxide
season
nitrification
nitrifier denitrification
relative abundance of functional genes
