| 稻田灌溉河流CH4和N2O排放特征及影响因素 |
| 摘要点击 1884 全文点击 623 投稿时间：2021-04-12 修订日期：2021-05-31 |
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| 中文关键词 甲烷(CH4) 氧化亚氮(N2O) 溶存浓度 通量 灌溉河流 影响因素 |
| 英文关键词 methane (CH4) nitrous oxide (N2O) dissolved concentrations emissions drainage river influencing factor |
| 作者 | 单位 | E-mail | | 吴双 | 南京农业大学资源与环境科学学院, 南京 210095
江苏省低碳农业与温室气体减排重点实验室, 南京 210095 | wushuang@njau.edu.cn | | 杨蔚桐 | 南京农业大学资源与环境科学学院, 南京 210095 | | | 盛扬悦 | 南京农业大学资源与环境科学学院, 南京 210095 | | | 方贤滔 | 南京农业大学资源与环境科学学院, 南京 210095 | | | 张天睿 | 南京农业大学资源与环境科学学院, 南京 210095 | | | 胡靖 | 南京农业大学资源与环境科学学院, 南京 210095 | | | 刘树伟 | 南京农业大学资源与环境科学学院, 南京 210095
江苏省低碳农业与温室气体减排重点实验室, 南京 210095 | swliu@njau.edu.cn | | 邹建文 | 南京农业大学资源与环境科学学院, 南京 210095
江苏省低碳农业与温室气体减排重点实验室, 南京 210095 | |
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| 中文摘要 |
| 随着农业氮肥大量施用，大量碳氮营养物质以淋溶或径流形式进入周边灌溉水体，使其成为甲烷（CH4）和氧化亚氮（N2O）的重要排放源.以我国东南部地区典型稻田灌溉河流为研究对象，于2014年9月至2016年9月连续两年原位观测表层水体CH4和N2O溶存浓度及其排放通量，旨在明确稻田灌溉河流CH4和N2O的排放特征、排放强度及其主要驱动因子.结果表明，观测期内c（CH4溶存）的年平均值为（390.57±43.95）nmol·L-1（92.80~1577.54 nmol·L-1），c（N2O溶存）的年平均值为（40.23±3.20）nmol·L-1（10.05~75.40 nmol·L-1）.CH4和N2O的排放通量（年平均）分别为（20.73±6.08）mg·（m2·h）-1和（34.30±7.12）μg·（m2·h）-1.CH4和N2O溶存浓度和排放通量整体上均呈现出春夏排放高，秋冬排放低的季节变化趋势.两年CH4累计排放总量为（3876.30±1153.96）kg·hm-2，N2O累计排放总量为（5.74±0.98）kg·hm-2.两者持续性全球增温潜势（SGWP，以CO2-eq计）平均为（87.99±15.73）t·（hm2·a）-1.CH4排放通量与水温、底泥可溶性有机碳（DOC）显著正相关，而与水体溶解氧（DO）显著负相关；N2O排放通量与水温、水中铵态氮（NH4+-N）和硝态氮（NO3--N）显著正相关，而与水体DO显著负相关.该研究可为科学估算我国农业灌溉流域CH4和N2O排放总量提供数据支撑和重要参考. |
| 英文摘要 |
| With the increase in fertilizer application, a large amount of carbon and nitrogen enters the irrigation water around farmland through leaching and runoff, which makes it become an important source of methane (CH4) and nitrous oxide (N2O) emissions. In this study, the dynamic characteristics of dissolved CH4 and N2O concentrations and emissions were observed from Sept. 2014-Sept. 2016. The purpose of this study was to investigate the inventory and the influencing factors of CH4 and N2O fluxes from a rice-paddy drainage river. The results showed that the dissolved c(CH4) in the rice-paddy drainage river ranged from 92.80 to 1577.54 nmol·L-1, with an annual mean value of (390.57±43.95) nmol·L-1. The dissolved c(N2O) in the rice-paddy drainage river ranged from 10.05 to 75.40 nmol·L-1, with an annual mean value of (40.23±3.20) nmol·L-1. The annual mean fluxes of CH4 and N2O were (20.73±6.08) mg·(m2·h)-1 and (34.30±7.12) μg·(m2·h)-1, respectively. The seasonal variations in dissolved CH4 and N2O concentrations and fluxes were similar with higher concentrations, and fluxes appeared in spring and summer; lower concentrations and fluxes appeared in fall and winter. The two-year total annual emissions of CH4 and N2O were (3876.30±1153.96) kg·hm-2 and (5.74±0.98) kg·hm-2, respectively. The annual mean value of the sustained-flux global warming potential (SGWP100a, CO2-eq) over the time span of 100 years was(87.99±15.73)t·(hm2·a)-1. The CH4 fluxes were positively correlated with water temperature and sediment-dissolved organic carbon (DOC), while negatively correlated with water dissolved oxygen (DO) concentration in the rice-paddy drainage river. Meanwhile, the N2O fluxes were positively correlated with water temperature, ammonium nitrogen (NH4+-N), and nitrate nitrogen (NO3--N), while negatively correlated with water dissolved oxygen (DO) concentration. This study may provide important reference for further understanding of total CH4 and N2O emissions of agricultural irrigation watersheds. |
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