A preliminary study on atmospheric N deposition in North China Plain

摘要

Anthropogenic-induced emissions of both oxidized and reduced reactive nitrogen have caused an increase in atmospheric nitrogen (N) deposition hi terrestrial ecosystems especially intensive agroecosystems. A monitoring network was established to determine the spatial and temporal variation in atmospheric N deposition, as deposition of dissolved inorganic nitrogen, in North China Plain (NCP) over a 2-year period. Bulk N deposition was as high as 28.0 kg/ha/yr on average in NCP with 32.5 kg/ha/yr in Beijing and 23.6 kg/ha/yr in Shandong and Hebei provinces. There was a positive relationship between rainfall and bulk N deposition, fitting a linear equation (r~2=0.62), and 60% N deposition occurred in summer, showing significant monthly variation due toprecipitation. Wet deposition of N accounted for 73 % of the bulk deposition, implying that dry deposition of N from dust is important as well. Furthermore, it was predicted that atmospheric N deposition would be much higher than our monitored value if dissolved organic nitrogen was taken into account.