title: CH4 and N2O emissions from China's beef feedlots with ad libitum and restricted feeding in fall and spring seasons.
abstract: Accurately quantifying methane (CH4) and nitrous oxide (N2O) emissions from beef operations in China is necessary to evaluate the contribution of beef cattle to greenhouse gas budgets at the national and global level. Methane and N2O emissions from two intensive beef feedlots in the North China Plain, one with a restricted feeding strategy and high manure collection frequency and the other with an ad libitum feeding strategy and low manure collection frequency, were quantified in the fall and spring seasons using an inverse dispersion technique. The diel pattern of CH4 from the beef feedlot with an ad libitum feed strategy (single peak during a day) differed from that under a restricted feeding condition (multiple peaks during a day), but little difference in the diel pattern of N2O emissions between two feeding strategies was observed. The two-season average CH4 emission rates of the two intensive feedlots were 230 and 198gCH4animal(-1)d(-1) and accounted for 6.7% and 6.8% of the gross energy intake, respectively, indicating little impact of the feeding strategy and manure collection frequency on the CH4 conversion factor at the feedlot level. However, the average N2O emission rates (21.2g N2Oanimal(-1)d(-1)) and conversion factor (8.5%) of the feedlot with low manure collection frequency were approximately 131% and 174% greater, respectively, than the feedlot under high frequency conditions, which had a N2O emission rate and conversion factor of 9.2g N2Oanimal(-1)d(-1) and 3.1%, respectively, indicating that increasing manure collection frequency played an important role in reducing N2O emissions from beef feedlots. In addition, comparison indicated that China's beef and dairy cattle in feedlots appeared to have similar CH4 conversion factors.
authors.affiliation: College of Resources and Environmental Sciences, Agricultural University of Hebei, 071000 Baoding, PR China.
authors.forename: Zhi
authors.initials: Z
authors.lastname: Lin
authors.affiliation: College of Resources and Environmental Sciences, Agricultural University of Hebei, 071000 Baoding, PR China.
authors.forename: Wenhua
authors.initials: W
authors.lastname: Liao
authors.affiliation: College of Resources and Environmental Sciences, Agricultural University of Hebei, 071000 Baoding, PR China.
authors.forename: Yuanyuan
authors.initials: Y
authors.lastname: Yang
authors.affiliation: College of Resources and Environmental Sciences, Agricultural University of Hebei, 071000 Baoding, PR China. Electronic address: zhilinggao@hotmail.com.
authors.forename: Zhiling
authors.initials: Z
authors.lastname: Gao
authors.affiliation: College of Resources and Environmental Sciences, Agricultural University of Hebei, 071000 Baoding, PR China.
authors.forename: Wenqi
authors.initials: W
authors.lastname: Ma
authors.affiliation: College of Resources and Environmental Sciences, Agricultural University of Hebei, 071000 Baoding, PR China.
authors.forename: Dianwu
authors.initials: D
authors.lastname: Wang
authors.affiliation: College of Animal Science and Technology, Agricultural University of Hebei, 071000 Baoding, PR China.
authors.forename: Yufeng
authors.initials: Y
authors.lastname: Cao
authors.affiliation: College of Animal Science and Technology, Agricultural University of Hebei, 071000 Baoding, PR China.
authors.forename: Jianguo
authors.initials: J
authors.lastname: Li
authors.affiliation: Mechanical and Electric Engineering College, Agricultural University of Hebei, 071000 Baoding, PR China.
authors.forename: Zhenjiang
authors.initials: Z
authors.lastname: Cai
mesh_terms: D000393:Air Pollutants / Q000378:metabolism*; D000822:Animal Husbandry; D000818:Animals; D002417:Cattle; D002681:China; D002940:Circadian Rhythm; D004032:Diet / Q000662:veterinary*; D008372:Manure / Q000032:analysis; D008697:Methane / Q000378:metabolism*; D009609:Nitrous Oxide / Q000378:metabolism*; D012621:Seasons
chemical_list: D000393:Air Pollutants; D008372:Manure; D009609:Nitrous Oxide; D008697:Methane
keywords: Ad libitum; Beef; Methane; Nitrous oxide; Restricted feeding