Attempt to correct grassland N2O fluxes biased by the DN-based opaque static chamber measurement

	Attempt to correct grassland N2O fluxes biased by the DN-based opaque static chamber measurement
	Ma, L; Zhang, W; Zheng, XH; Yao, ZS; Zhang, H; Wang, R; Zhu, B; Wang, K; Liu, CY; Cao, GM
刊名	ATMOSPHERIC ENVIRONMENT
	2021
卷号	264
英文摘要	The DN method, referred to a gas chromatography (GC) method uses dinitrogen as a carrier gas, in combination with opaque static chamber, was widely used to measure grassland nitrous oxide (N2O) fluxes. However the N2O fluxes were positively biased by this method, as compared to the other GC methods. Currently, no study was conducted through simultaneous measurements of N2O fluxes by DN and other GC methods to correct the biased fluxes by the DN-based opaque static chamber measurement in grasslands. For this purpose, DN and DN-CO2 methods (dinitrogen is also used as a carrier gas, and carbon dioxide as a make-up gas), both in combination with opaque static chambers, were compared through paired measurements in alpine pastures, including meadow as grazed pasture (MGP), ungrazed meadow (UGM), zokor mounds in meadow (ZMM), dung patches in meadow (DPM) and peat wetland as pasture (PWP). The DN method resulted in N2O fluxes about 11.1, 12.1 and 7.5 times higher (p < 0.05) in MGP, UGM and ZMM, respectively, while there was no significant difference between the two methods in DPM or PWP. All the paired fluxes with DN-CO2 measurements > 15 mu g N m(-2) h(-1) showed positive correlations between the N2O fluxes measured by the two methods (p < 0.0001), whereas the other measurements showed a negative linear correlation of flux differences between the two methods versus DNmeasured fluxes (p < 0.0001). We further developed correction approaches for DN-measured fluxes and validated these corrections using the data from this study or those observed previously in different terrestrial ecosystems by other studies. The estimated annual N2O emissions from grasslands in China would be reduced from 288.1 to 98.7-142.3 Gg N yr(-1) (1 Gg = 10(9) g) if DN-measured fluxes were corrected using the approaches established in this study. We concluded that the DN method should be replaced by other GC methods or non-GC techniques to measure N2O fluxes from terrestrial ecosystems. Moreover, our study provides a valid approach to correct DN-measured N2O fluxes from global grasslands.
内容类型	期刊论文
源URL	[http://210.75.249.4/handle/363003/61367]
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	Ma, L,Zhang, W,Zheng, XH,et al. Attempt to correct grassland N2O fluxes biased by the DN-based opaque static chamber measurement[J]. ATMOSPHERIC ENVIRONMENT,2021,264.
APA	Ma, L.,Zhang, W.,Zheng, XH.,Yao, ZS.,Zhang, H.,...&Wang, YH.(2021).Attempt to correct grassland N2O fluxes biased by the DN-based opaque static chamber measurement.ATMOSPHERIC ENVIRONMENT,264.
MLA	Ma, L,et al."Attempt to correct grassland N2O fluxes biased by the DN-based opaque static chamber measurement".ATMOSPHERIC ENVIRONMENT 264(2021).