应用反演式气体扩散技术测定奶牛场甲烷的排放特征

Determination of Methane Emissions from a Dairy Feedlot Using an Inverse Dispersion Technique

为了准确揭示奶牛场的甲烷排放特征,在我国首次采用国际上最新的反演式气体扩散技术与开路式激光仪相结合的研究方法,分别于2009年冬季和2010年春季测定了保定市某奶牛养殖基地甲烷的排放特征,测定期间养殖基地的动物总量平均为1200头。结果表明,奶牛养殖场尺度的甲烷排放在冬季和春季均呈现出规律性的日排放特征,即养殖场甲烷日排放高峰出现在0500、1130和1630,排放高峰的出现时间与上料时间基本吻合;冬季和春季试验期间该养殖场的反刍和粪尿甲烷总排放量分别为0.31t.d-1和0.36t.d-1,养殖基地内整个牛群平均每头牛的反刍和粪尿甲烷日排放总量分别为0.26kg.d-1和0.30kg.d-1,春季的甲烷日排放量比冬季约高16.7,初步揭示了奶牛场尺度甲烷排放的季节性差异。

Methane emission from dairy feedlot in China is one important source of global methane budget due to the large global warming potential（a factor of 25 in comparison with CO2）.To indicate methane emission patterns on dairy feedlot in North China,a combination of an inverse dispersion technique and open-path laser was used to quantify patterns of methane emissions on a dairy feedlot（Baoding,Hebei）during winter and spring seasons.During these two measurement seasons,the total animal herd was 1 200 heads in average.Results showed that both in winter and spring seasons,methane emissions from the selected dairy feedlot were characterized with a apparent diurnal pattern,that was,the emission peaks occurred at 05：00,11：30 and 16：30,respectively,which was generally in agreement with the schedule of feeding activities;it also indicated that total daily emission rate of methane including enteric formation and manure storage within feedlot during winter and spring seasons were 0.31 t·d-1 and 0.36 t·d-1,and on the per capita base including total animal herd,methane emission rates were 0.26 t·d-1 and 0.30 kg·d-1,where methane emission rate during spring season was about 16.7 greater than winter season,thus a relatively large seasonal difference on methane emission rates was identified.