Methane and nitrous oxide analyzer comparison and emissions from dairy freestall barns with manure flushing and scraping
Methane and nitrous oxide analyzer comparison and emissions from dairy freestall barns with manure flushing and scraping
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DOI：
10.1016/j.atmosenv.2014.10.039
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发表时间：
2015-01-01
影响因子：
5
通讯作者：
Bogan, Bill W.
中科院分区：
文献类型：
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作者：
Cortus, Erin L.;Jacobson, Larry D.;Bogan, Bill W.
2008年至2010年的19个月期间，在位于美国威斯康星州的两个横流通风奶牛自由放养谷仓进行了连续甲烷（CH 4）和一氧化二氮（N2 O）排放测量。在国家空气排放监测研究中对两个横流机械通风建筑（275和375头奶牛容量）进行了评估。2008年9月，谷仓的粪便收集系统从使用粪便池污水冲洗开放式排水沟改为拖拉机刮。光声多气体分析仪（PAMGA）和直接甲烷/非甲烷碳氢化合物分析仪（GC-FID）提供了13个月的甲烷（CH 4）并排测量。PAMGA还测量了一氧化二氮（N2 O），并与气体过滤相关分析仪（GFC）进行了为期六个月的并排比较。通过记录127 cm直径排气扇的运行时间来测量畜舍通风率。所有125个皮带驱动的排气扇都是相同的，并且使用风扇评估计算系统（FANS）进行现场气流测量，在开始时进行一次，在测试期间进行两次。每日CH 4和N2 O排放率分别计算了约19个月和6个月期间，每个谷仓，头，动物单位，占地面积和谷仓容量的基础。分析仪的浓度测量之间的差异与水蒸气和其他气体进行了比较。分析仪类型对CH 4平均排放率（p < 0.001）和N2 O平均排放率（p < 0.05）有显著影响。根据GC-FID对甲烷的测量，甲烷的日均排放量约为290 g Au（-1）d（-1）（390 g cow（-1）d（-1）），季节影响非常有限。在改变粪肥收集方法之前和之后，甲烷排放率变化不大，这表明大部分甲烷排放直接来自奶牛的肠道损失。基于全球森林覆盖率的平均日平均N2 O排放率非常低，大约只有690 mg Au（-1）d（-1）（970 mg cow（-1）d（-1））。施肥量的变化对N2 O排放无明显影响。(C)2014爱思唯尔有限公司版权所有。
Continuous methane (CH4) and nitrous oxide (N2O) emission measurements were conducted at two crossflow-ventilated dairy freestall barns located in the state of Wisconsin, USA during a 19-month period from 2008 to 2010. The two cross-flow mechanically ventilated buildings (275 and 375 cow capacities) were evaluated in the National Air Emissions Monitoring Study. In September of 2008, the barns' manure collection systems were changed from flushing open gutter using manure basin effluent to a tractor scrape. A photoacoustic multi-gas analyzer (PAMGA) and a direct methane/non-methane hydrocarbon analyzer (GC-FID) provided side-by-side measurements of methane (CH4) for 13 months. The PAMGA also measured nitrous oxide (N2O), and a side-by-side comparison was performed with a gas-filter correlation analyzer (GFC) for six months. Barn ventilation rates were measured by recording run times of the 127-cm diameter exhaust fans. All 125 belt-driven exhaust fans were identical, and in situ airflow measurements using the Fan Assessment Numeration System (FANS) were conducted once at the beginning and twice during the test. Daily CH4 and N2O emission rates were calculated over approximately 19 and 6 month periods respectively, on per barn, head, animal unit, floor area space and barn capacity bases. The differences between the analyzers' concentration measurements were compared in conjunction with water vapor and other gases. The analyzer type had a significant impact on the average CH4 emission rate (p < 0.001) and the average N2O emission rate (p < 0.05). Based on the CH4 measurements with the GC-FID, average daily mean CH4 emissions were approximately 290 g AU(-1) d(-1) (390 g cow(-1) d(-1)) with very limited seasonal effects. Little variation was observed in CH4 emission rates before and after the change in manure collection method, suggesting that most of the CH4 emissions were enteric losses directly from the cows. The average daily mean N2O emission rates based on the GFC were very low, with an approximate rate of only 690 mg AU(-1) d(-1) (970 mg cow(-1) d(-1)). The change in manure collection had no apparent effect on N2O emission. (C) 2014 Elsevier Ltd. All rights reserved.