Atmospheric NO2 and NH3 deposition into a typical agro-ecosystem in Southeast China

Abstract

The dry deposition of atmospheric nitrogen (including NO₂ and NH₃) into a typical agro-ecosystem in Southeast China during 2006–2007 was estimated. Results indicated that the dry deposition velocities of NO₂ and NH₃ ranged from 0.04–0.24 cm s⁻¹ and 0.09–0.47 cm s⁻¹, respectively. The higher values appeared in the non-crop growing period. Concentrations of atmospheric NO₂ and NH₃ ranged from 24.64–104.10 μgN m⁻³ and 14.40–389.6 μgN m⁻³, respectively. Variation of the NH₃ mixing ratio showed a clear double-peak. NO₂ and NH₃ deposition fluxes were 74.68–80.75 kgN ha⁻¹, which was equivalent to 162.4 and 175.5 kg ha⁻¹ of urea applied in 2006–2007. The N deposition fluxes were 13.91–40.38 and 5.33–22.73 kgN ha⁻¹ in peanut and rice growing periods, accounting for 8.18%–40.38% and 2.13%–23.06% of N fertilizer usages, respectively. NO₂ and NH₃ deposition were significant for the red soil farmland.