福建省农业源甲烷排放估算及其特征分析

Estimation and analysis of the methane emissions from agricultural activities of Fujian province

农业领域的稻田和畜禽养殖是温室气体甲烷（CH4）的重要排放源,估算省级农业源甲烷的排放量,并分析其排放特征,对进一步提出符合福建省实际情况、在技术经济上可行的减排措施有重要意义。本研究基于福建省农业活动水平数据,根据IPCC国家温室气体排放清单编制指南,估算了1991—2010年福建省农业源CH4排放量。结果表明：（1）1991-1995、1996-2000、2001-2005、2006-2010年间福建省农业源CH4年平均排放量分别为46.50×104、44.38×104、37.87×104、33.12×104t,呈降低趋势。其中,稻田CH4排放的贡献较大,4个时期年平均排放量分别为31.11×104、29.49×104、22.16×104、18.80×104t,占全省农业源CH4排放总量的56.76%-66.90%;而反刍动物肠道发酵和畜禽粪便管理的CH4排放量在20年间的变化不明显,分别为6.27×104~10.31×104t和4.95×104-7.20×104t。（2）2010年,福建省农业源CH4排放高值区主要分布在龙岩市、南平市和三明市,占全省农业源CH4排放总量的51%;稻田CH4排放的高值区主要分布在南平市、三明市和龙岩市,占全省稻田CH4排放总量的56%,应优先考虑削减这些地区的稻田CH4排放;畜禽CH4排放的高值区主要分布在龙岩市、漳州市和泉州市,占全省畜禽CH4排放总量的52%,应优先考虑削减这些地区的畜禽CH4排放。近20年福建省农业源CH4排放量呈下降趋势,主要是由于水稻播种面积的逐年减少,未来农业源CH4排放下降速度可能会放慢,因此控制水稻CH4排放的重点应放在灌溉管理、施肥管理、稻谷品种选择等方面;而控制畜禽CH4排放的关键是优化畜牧业结构,大力推进规模养殖,使畜禽品种、饲养技术和畜禽排泄物处理设施得到改进,提升单位畜禽饲养量的畜产品产出量,进而减少温室气体排放。研究结果可为决策者有针对性地制定福建农业CH4排放控制政策和对策措施,降低农业源CH4排放量提供基础资料。

Paddy fields and livestocks are the important sources of atmospheric methane （CH4）. Based on the agricultural data of Fujian province, according to the methodology guidelines of IPCC, the CH4 emissions from agricultural activities of Fujian province were estimated and analyzed from 1991 to 2010, which had an important significance to putting forward the suitable measures for mitigating the CH4 emissions. The results showed that （1） the annual averaged CH4 emissions from agricultural activities were gradu- ally decreased, which were 46.50×10^4, 44.38×10^4, 37.87×10^4 and 33.12×10^4 tons during 1991-1995, 1996-2000, 2001-2005 and 2006-2010, respectively. The annual averaged CH4 emissions from rice paddies were 31.11×10^4, 29.49×10^4, 22.16×10^4, 18.80×10^4 tons at four stages, respectively, which accounted for 56.76%-66.90% of the total CH4 emissions of agricultural activities. The CH4 emissions from ruminant intestinal canal and livestock manures had no obvious change, which were 6.27×10^4-10.31×10^4 tons and 4.95×10^4-7.20×10^4tons from 1991 to 2010, respectively. （2） In 2010, the CH4 emissions from agricultural activities were mainly concentrated in the districts of Longyan, Nanping and Sanming, which accounted for 56% of the total CH4 emissions. The CH4 emis- sions from rice paddies were mainly concentrated in the districts ofNanping, Sanming and Longyan, which accounted for 56% of the CH4 emissions from rice paddies; while the CH4 emissions from livestocks were mainly Concentrated in the districts of Longyan, Zhangzhou and Quanzhou, which accounted for 52% of the CH4 emissions from animals. These districts are questions which take precedence of others. In recent 20 years, the CH4 emission has a decline trend mainly due to the decrease of rice-planted area. In future, the CH4 emission rate may slow down. Therefore the measures for mitigating the CH4 emissions from rice paddies should be focused on irrigation, fertilization, rice varieties selection, etc. While the measures for mitigating the CH4 emissions from livestocks should be focused on the optimization of animal husbandry structure, promoting the large-scale livestock raising, improving the rais- ing technologies, etc. The results will provide a scientific basis for policy maker to mitigate the CH4 emission from agricultural activ- ities of Fujian province.