Soil degassing during watering: An overlooked soil N2O emission process

• Published in: Environmental pollution (1987) 2018-11, Vol.242, p.257-263
• Main Authors: Xu, Junzeng, Wei, Qi, Yang, Shihong, Liao, Linxian, Qi, Zhiming, Wang, Weiguang
• Format: Article
• Language: English
• Subjects: Nitrous oxide; Rainfall; Shallow groundwater lifting; Soil degassing; Watering
• ISSN: 0269-7491; 1873-6424
• DOI: 10.1016/j.envpol.2018.06.103

Pulse diffusive nitrous oxide (N2O) emission following water application is well documented, whereas N2O emission caused by soil water-air displacement during the watering process (termed as soil degassing) has been largely overlooked. Watering-induced N2O emissions from ten different soils in China were quantified, and found to range from 74.4 ± 6.7 to 678.1 ± 36.6 μg N2O m−2 h−1 in surface watered (SW) soils, and from 45.6 ± 4.4 to 358.1 ± 23.6 μg N2O m−2 h−1 in subsurface watered (SUW) soils. These N2O fluxes were much larger than the diffusive N2O flux from the same soil either under dry (7.9%–9.6% water filled pore space, WFPS) or wet (85.1%–93.6% WFPS) conditions. The watering process (the water infiltration process upon irrigation/rainfall or the process of shallow groundwater uplifting) resulted in massive N2O emissions. [Display omitted] •Soil degassing during watering process emitted massive N2O emission.•Watering method had great effect on degassing process of soil N2O emission into the atmosphere.•N2O fluxes by soil degassing were 10.0–346.1 and 2.6–27.4 times of those from dry and wet soil. An overlooked soil N2O emission process was confirmed in current research.