Methane emission from rice fields in mainland China: Amount and seasonal and spatial distribution
Methane emission from rice fields in mainland China: Amount and seasonal and spatial distribution
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DOI：
10.1029/2002jd003182
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发表时间：
2003-08
影响因子：
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通讯作者：
Xiaoyuan Yan;Z. Cai;T. Ohara;H. Akimoto
中科院分区：
文献类型：
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作者：
Xiaoyuan Yan;Z. Cai;T. Ohara;H. Akimoto
中国是世界上最大的大米生产国。自20世纪80年代末以来，稻田的甲烷（CH4）排放量已被广泛测量。本研究收集了在23个地点进行的总计204个季节处理测量的现有实地研究结果。对这些数据的分析表明，有机肥、动物粪便和农作物秸秆等有机物质的输入使CH4排放量增加了2倍。间歇灌溉稻田的平均CH4通量为连续淹水稻田的53%；晚稻田平均CH4排放通量分别是早稻田和单稻田的1.6倍和2.3倍。排放因子存在区域差异，并呈现由南向北减少的趋势。根据早期对中国稻田CH4排放的估计，以及最近关于作物残茬和绿肥使用的报告，可以推测中国一半的稻田接受有机投入。根据田间调查试验中各种水管理事件发生的频率，以及个别报告中的具体陈述，可以推测三分之二的灌溉稻田间歇性被淹。在此假设的基础上，基于1995年水稻种植面积数据，估计中国大陆生长季稻田CH4排放量为7.67 Tg yr - 1，范围为5.82 ~ 9.57 Tg yr - 1，这是由于有机投入地区的不确定性和间歇性灌溉的影响。在早稻、晚稻和单稻中建立了广义的季节通量模式。根据这些模式和水稻日历估计了每月的排放分布。8月份的排放率最高。在空间上，排放热点包括湖南洞庭湖平原、江西鄱阳湖平原、浙江钱塘江三角洲和四川盆地。中国大陆近90%的CH4排放发生在23°N至33°N之间。
[1] China is the largest rice producer in the world. Methane (CH4) emission from its rice fields has been widely measured since the late 1980s. This study collected the results of available field research, totaling 204 season-treatment measurements conducted on 23 sites. Analysis of these data shows that input of organic material, such as green manure, animal waste, and crop straw, increases CH4 emission by a factor of 2. Average CH4 flux from intermittently irrigated rice fields is 53% of that from continuously flooded rice fields; and average CH4 emission flux from late rice fields is 1.6 and 2.3 times greater than flux from early and single rice fields, respectively. There are regional differences in emission factors and a trend of decreasing emission from south to north. On the basis of earlier estimates of CH4 emission from Chinese rice fields, and recent reports on the use of crop residue and green manure, it is presumed that half of the rice fields in China receive organic input. From the frequency of various water management events indicated in the surveyed field experiments, as well as from specific statements in individual reports, it is presumed that 2/3 of irrigated rice fields have been intermittently flooded. On the basis of these assumptions, the region-specific emission factors, and 1995 data on rice cultivation area, CH4 emission from growing-season rice fields in Mainland China was estimated to be 7.67 Tg yr−1, ranging from 5.82 to 9.57 Tg yr−1, due to uncertainties in the areas receiving organic inputs, and intermittent irrigation. Generalized seasonal flux patterns were developed for early, late, and single rice. Monthly distributions of emission were estimated from these patterns and rice calendars. The highest emission rate occurred in August. Spatially, emission hot spots included the plains of Dongting Lake in Hunan Province, Boyang Lake in Jiangxi Province, the delta region of Qiantang River in Zhejiang Province, and the Sichuan Basin. Nearly 90% of all Mainland China CH4 emission occurred between 23°N and 33°N.