Surface-exchange of NOx and NH_3 above a winter wheat field in the Yangtze Delta, China

Article type: Research Article

Authors: FANG, Shuan-gxi | ZHANG, Yi | MU, Yu-jing

Affiliations: Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China

Note: [] Corresponding author. E-mail: [email protected]

Abstract: A four-dynamic-chamber system was constructed to measure NOx and NH_3 surface-exchange between a typical wheat field and the atmosphere in the Yangtze Delta, China. The average fluxes of NO, NO_2 and NH_3 were 79, −5.6 and −5.1 ngN/(m^2·s), and 91, −1.8 and 23 ngN/(m^2·s), respectively for the wheat field and the bare soil. The NO flux was positively correlated with soil temperature and the fluxes of NO_2 and NH_3 were negatively correlated with their ambient concentrations during the investigated period. The compensation point of NO_2 between the wheat field and the atmosphere was 11.9 μg/m^3. The emissions of NO-N and NH_3-N from the urea applied to the wheat field were 2.3% and 0.2%, respectively, which indicated that the main pathway of N loss from the investigated winter wheat field was NO. Application of a mixture of urea and lignin increased the emissions of NO, but also greatly increased the yield of the winter wheat.

Keywords: NOx, NH[TeX:] _3, flux, surface-exchange

Journal: Journal of Environmental Sciences, vol. 18, no. 4, pp. 689-700, 2006