Year-round measurements of nitrous oxide emissions and direct emission factors in extensively managed croplands under an alpine climate

	Year-round measurements of nitrous oxide emissions and direct emission factors in extensively managed croplands under an alpine climate
	Liu, Chunyan; Hu, Xiaoxia; Zhang, Wei; Zheng, Xunhua; Wang, Rui; Yao, Zhisheng; Cao, Guangmin
刊名	AGRICULTURAL AND FOREST METEOROLOGY
	2019
卷号	274
关键词	Soil freeze-thaw Nitrogen use efficiency Nitrogen surplus Highland barley Oilseed rape Qinghai-Tibetan Plateau
英文摘要	Estimates of China's agricultural nitrous oxide (N2O) emission inventory are mainly based on data for intensively managed croplands in the monsoon zone. Observations of N2O fluxes and direct emission factors (EF(d)s) remain limited in the non-monsoon zone in China. In this study, year-round measurements of yields, meteorological and soil environmental factors, and N2O fluxes were conducted in highland barley (HB, with the application of synthetic fertilizers) and oilseed rape (OR, with the mixed application of air-dried sheep manure and synthetic fertilizers) cropping systems with typical extensive management in the Qinghai-Tibetan Plateau. The cumulative N2O emissions during the freeze-thaw period (0.10 and 0.31 kg N ha(-1)) and annual scale (0.35 and 0.70 kg N ha(-1) yr(-1) in the HB and OR fields, respectively) were in the low range of globally reported freeze-thaw emissions from seasonally frozen croplands. The annual EF(d)s were 0.19% +/- 0.11% and 0.04% +/- 0.14% in the HB and OR fields, respectively, which were much lower than the national average and IPCC default values. The extensive management (low fertilization rates, aboveground plant nitrogen removal, and rain-fed agriculture) and alpine climate led to low emissions and EF(d)s in the croplands of the Qinghai-Tibetan Plateau. Although the annual N2O emissions and EF(d)s were relatively low, extensive management still needs to be optimized to maintain the sustainability of agricultural production on the plateau because of the extremely low nitrogen use efficiencies (crop recovery efficiency of applied nitrogen: 0.2 kg N kg(-1) N) and negative nitrogen surpluses (-58.7 and -8.0 kg N ha(-1) yr(-1) in the HB and OR fields, respectively). To reduce the uncertainty in the estimates of global and national emission inventories, more studies should be conducted in the non-monsoon zone owing to the peculiarity of management strategy and climate, and the dramatic expansion of cropland area.
内容类型	期刊论文
源URL	[http://210.75.249.4/handle/363003/59722]
专题	西北高原生物研究所_中国科学院西北高原生物研究所
推荐引用方式 GB/T 7714	Liu, Chunyan,Hu, Xiaoxia,Zhang, Wei,et al. Year-round measurements of nitrous oxide emissions and direct emission factors in extensively managed croplands under an alpine climate[J]. AGRICULTURAL AND FOREST METEOROLOGY,2019,274.
APA	Liu, Chunyan.,Hu, Xiaoxia.,Zhang, Wei.,Zheng, Xunhua.,Wang, Rui.,...&Cao, Guangmin.(2019).Year-round measurements of nitrous oxide emissions and direct emission factors in extensively managed croplands under an alpine climate.AGRICULTURAL AND FOREST METEOROLOGY,274.
MLA	Liu, Chunyan,et al."Year-round measurements of nitrous oxide emissions and direct emission factors in extensively managed croplands under an alpine climate".AGRICULTURAL AND FOREST METEOROLOGY 274(2019).