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以牛羊为主的反刍动物养殖是我国甲烷的首要排放源,其中又以牛的排放占主导。我国的养殖牛中,黄牛的数量最为庞大,占总存栏牛的56%。在以往有关反刍动物甲烷排放的研究中,着重点多在于排放因子的测定及依据测定结果估算国家尺度的排放源清单。但是,对于反刍动物种群特征及环境因子变化造成的动物甲烷排放在空间和季节的差异却较少关注。本研究收集了我国不同地区46个亚科黄牛的个体特性数据及其生态因子,结合IPCC的反刍动物甲烷排放估算方法,分析了我国2005年黄牛甲烷排放因子的空间差异及其季节变化特征。结果表明,总体上农区肠道发酵排放因子,除4-6月因役用强度大的原因,而排放略高于牧区外,其他月份均小于牧区,而农区粪便管理排放因子全年高于牧区。肠道发酵排放因子在夏季小于其他季节,其月均排放因子为4.48 kg/head/m,粪便管理排放因子则表现出相反的季节格局,夏季粪便管理月均排放因子为0.44 kg/head/m。在7个大的分区中,肠道发酵年排放因子最大、最小区域分别为黄土高原区71.0 kg/head/a和西南区55.2 kg/head/a;粪便管理年排放因子最大、最小区域分别为东南区5.4 kg/head/a和青藏区0.1 kg/head/a。
Breeding of ruminants, mainly cattle and sheep, is the primary source of methane emissions in China, of which the discharge of cattle is also the dominant one. China’s breeding cattle, the largest number of cattle, cattle accounted for 56% of the total population. In the past, studies on methane emissions from ruminants focused more on the determination of emission factors and on the national scale inventory of emissions sources based on the results of the measurements. However, less attention has been paid to the differences in space and season of methane emissions from animals due to changes in ruminant population characteristics and environmental factors. In this study, individual characteristics data and ecological factors of 46 subfamilies in different regions of China were collected. Combined with IPCC estimation of methane emissions from ruminants, the spatial variation of methane emission factors and their seasonal variations in China in 2005 were analyzed. The results showed that, in general, the emission factors of gut fermentation in rural areas were slightly lower than those in pastoral areas except for April to June due to the high utilization of labor intensity, while the other months were smaller than those in pastoral areas, while the annual discharge of manure management in rural areas In pastoral areas. The emission factors of gut fermentation in summer were less than those of other seasons, with an average monthly discharge factor of 4.48 kg / head / m and an excrement management emission factor showing an opposite seasonal pattern with an average of 0.44 kg / head / m for summer manure management . In the seven large subzones, the annual discharge factor of intestinal fermentation was the largest with the minimum area of 71.0 kg / head / a in the Loess Plateau and 55.2 kg / head / a in the southwest of the Loess Plateau respectively; the discharge factor of manure management was the largest in the smallest subregion 5.4 kg / head / a in southeast area and 0.1 kg / head / a in Qinghai-Tibet area.