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Soil degassing during watering: An overlooked soil N2O emission process

Author:
Xu, Junzeng, Wei, Qi, Yang, Shihong, Liao, Linxian, Qi, Zhiming, Wang, Weiguang
Source:
Environmental pollution 2018 v.242 pp. 257-263
ISSN:
0269-7491
Subject:
greenhouse gas emissions, groundwater, irrigation, nitrous oxide, rain, soil, China
Abstract:
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.
Agid:
6053469