%0 Journal Article
%T Diurnal and Seasonal Patterns of Methane Emissions from a Dairy Operation in North China Plain
%A Zhiling Gao
%A Huijun Yuan
%A Wenqi Ma
%A Jianguo Li
%A Xuejun Liu
%A Raymond L. Desjardins
%J Advances in Meteorology
%D 2011
%I Hindawi Publishing Corporation
%R 10.1155/2011/190234
%X In China, dairy cattle managed in collective feedlots contribute about 30% of the milk production and are believed to be an important contributor to national methane emissions. Methane emissions from a collective dairy feedlot in North China Plain (NCP) were measured during the winter, spring, summer, and fall seasons with open-path lasers in combination with an inverse dispersion technique. Methane emissions from the selected dairy feedlot were characterized by an apparent diurnal pattern with three peaks corresponding to the schedule of feeding activities. On a per capita basis, daily methane emission rates of these four seasons were 0.28, 0.32, 0.33, and 0.30£¿kg£¿head£¿1£¿d£¿1, respectively. In summary, annual methane emission rate was 112.4£¿kg£¿head£¿1£¿yr£¿1 associated with methane emission intensity of 32.65£¿L CH4 L£¿1 of milk and potential methane conversion factor Ym of 6.66% of gross energy intake for mature dairy cows in North China Plain. 1. Introduction The dairy cow population in China has increased from 40,000 animals to 13.25 million animals during the period of 1949¨C2006. Dairy production has become one of the most profitable and increasing industries in the agriculture sector in China. For example, in 2008, the GDP originated from Chinese dairy industry was £¤101.5 billion, which accounted for about 10% of the total animal production and about 3.0% of total agricultural production [1]. Considerable efforts have been made to estimate enteric methane emissions from dairy cows in China in order to improve the accuracy of national methane inventory [2¨C4]. These inventories are mainly based on the Intergovernmental Panel on Climate Change (IPCC) methodology. However, many studies have demonstrated that methane emissions from ruminants are strongly influenced by factors such as feeding activity, composition of feedstuffs, and use of additives, which are not included in the IPCC methodology. In China, management practices are frequently different from one dairy facility to another; hence, large uncertainties in the inventory estimates are anticipated. Dairy cattle in China are being managed in different types of dairy facilities. Based on the number of animals, these facilities are either classified as intensive, collective, or household level operations [5]. As reported by Ma et al. [6], about 45%, 29.3%, and 25.9% of the Chinese dairy cow population is held in household, collective, and intensive dairy facilities, respectively, and the collective dairy feedlot has been considered a transition phase that links the transformation from household to
%U http://www.hindawi.com/journals/amete/2011/190234/