Eddy covariance methane flux measurements over a grazed pasture: effect of cows as moving point sources
Eddy covariance methane flux measurements over a grazed pasture: effect of cows as moving point sources
复制标题
放牧牧场上的涡流协方差甲烷通量测量：奶牛作为移动点源的影响
DOI：
10.5194/bg-12-3925-2015
复制
发表时间：
2015
期刊：
影响因子：
4.9
通讯作者：
C. Ammann
中科院分区：
文献类型：
--
作者：
R. Felber;A. Münger;A. Neftel;C. Ammann
抽象的。反刍动物产生的甲烷（CH 4）占全球农业温室气体排放量的三分之一。涡动相关（EC）技术已被广泛应用于各种通量站点，以研究生态系统的二氧化碳交换。由于快速CH 4分析仪的发展，许多通量站点的仪器已经针对这些气体进行了修改。然而，由于放牧动物引起的CH 4点源时空分布不均，EC在牧场上的应用具有挑战性。我们应用EC测量在一个放牧季节的牧场与20头奶牛（平均产奶量：22.7公斤d-1）管理的轮牧制度。通过GPS跟踪器记录个体奶牛的位置，以使用足迹模型将通量归因于动物排放。甲烷通量与奶牛的足迹高达2个数量级高于生态系统通量没有奶牛。奶牛的平均排放量为423 ± 24 g CH 4 head−1 d−1（本研究的最佳估计值），与文献中报告的动物呼吸室测量值相符。然而，一个系统的影响源和EC塔之间的距离对奶牛的排放量被发现，这是由于使用的分析足迹模型。我们表明，EC方法允许一个牧场上的奶牛CH 4排放量，如果数据评估调整为这个目的，如果一些奶牛分布信息是可用的。
Abstract. Methane (CH4) from ruminants contributes one-third of global agricultural greenhouse gas emissions. Eddy covariance (EC) technique has been extensively used at various flux sites to investigate carbon dioxide exchange of ecosystems. Since the development of fast CH4 analyzers, the instrumentation at many flux sites has been amended for these gases. However, the application of EC over pastures is challenging due to the spatially and temporally uneven distribution of CH4 point sources induced by the grazing animals. We applied EC measurements during one grazing season over a pasture with 20 dairy cows (mean milk yield: 22.7 kg d−1) managed in a rotational grazing system. Individual cow positions were recorded by GPS trackers to attribute fluxes to animal emissions using a footprint model. Methane fluxes with cows in the footprint were up to 2 orders of magnitude higher than ecosystem fluxes without cows. Mean cow emissions of 423 ± 24 g CH4 head−1 d−1 (best estimate from this study) correspond well to animal respiration chamber measurements reported in the literature. However, a systematic effect of the distance between source and EC tower on cow emissions was found, which is attributed to the analytical footprint model used. We show that the EC method allows one to determine CH4 emissions of cows on a pasture if the data evaluation is adjusted for this purpose and if some cow distribution information is available.
影响因子：
4.3
作者：
A. Graf;A. Boer;A. Moene;H. Vereecken
通讯作者：
A. Graf;A. Boer;A. Moene;H. Vereecken