Enhanced N2O Production Induced by Soil Salinity at a Specific Range

International Journal of Environmental Research and Public Health

Haiyu Wang¹  Qi Wei¹  Boyi Liu¹  Linxian Liao¹  Shimeng Liu¹  Zhiming Qi²  Junzeng Xu³  Yawei Li³ 

[1] College of Agricultural Science and Engineering, Hohai University, Nanjing 210098, China;Department of Bioresource Engineering, McGill University, Sainte-Anne-de-Bellevue, QC H9X 3V9, Canada;State Key Laboratory of Hydrology—Water Resources and Hydraulic Engineering, Hohai University, Nanjing 210098, China;

关键词: soil salinity;    N₂O emission;    soil inorganic N;    nitrification;   

DOI  :  10.3390/ijerph17145169

来源: DOAJ

【 摘 要 】

Nitrous oxide (N₂O) as a by-product of soil nitrogen (N) cylces, its production may be affected by soil salinity which have been proved to have significant negative effect on soil N transformation processes. The response of N₂O production across a range of different soil salinities is poorly documented; accordingly, we conducted a laboratory incubation experiment using an array of soils bearing six different salinity levels ranging from 0.25 to 6.17 dS m⁻¹. With ammonium-rich organic fertilizer as their N source, the soils were incubated at three soil moisture ( $\theta$ ) levels—50%, 75% and 100% of field capacity ( ${\theta }_{\mathrm{fc}}$ )—for six weeks. Both N₂O fluxes and concentrations of ammonium, nitrite and nitrate (NH₄⁺-N, NO₂⁻-N and NO₃⁻-N) were measured throughout the incubation period. The rates of NH₄⁺-N consumption and NO₃⁻-N accumulation increased with increasing soil moisture and decreased with increasing soil salinity, while the accumulation of NO₂⁻-N increased first then decreased with increasing soil salinity. N₂O emissions were significantly promoted by greater soil moisture. As soil salinity increased from 0.25 to 6.17 dS m⁻¹, N₂O emissions from soil first increased then decreased at all three soil moisture levels, with N₂O emissions peaking at electric conductivity (EC) values of 1.01 and 2.02 dS m⁻¹. N₂O emissions form saline soil were found significantly positively correlated to soil NO₂⁻-N accumulation. The present results suggest that greater soil salinity inhibits both steps of nitrification, but that its inhibition of nitrite oxidation is stronger than that on ammonia oxidation, which leads to higher NO₂⁻-N accumulation and enhanced N₂O emissions in soil with a specific salinity range.

【 授权许可】

Unknown