Atmospheric Nitrogen and Phosphorus Deposition at Three Sites in Nanjing, China, and Possible Links to Nitrogen Deposition Sources

Atmospheric deposition is a global and increasing threat to ecosystem function. Here, we analyzed bulk and wet deposition of inorganic N, total phosphorus (TP) and N-15 of NH4-N and NO3-N at three sites in Nanjing from March 2010 to February 2012. Results showed that bulk deposition fluxes of inorganic N and TP averaged 54.82kgNha(-1)year(-1) and 1.82kgPha(-1)year(-1), respectively. The N/P bulk deposition ratio reached 30/1, leading ecosystems toward P-limitation. Wet deposition fluxes of inorganic N and TP were 25.65kgNha(-1)year(-1) and 1.29kgPha(-1)year(-1), respectively, suggesting the potential contribution of inorganic N from dry deposition. Based on the N-15 values of NH4-N and NO3-N and model results, we found that chemical fertilizers and animal manures contributed to the reduced N deposition and fossil fuel and soil emissions contributed to the oxidized N deposition, depending upon the time and site. Agriculture sector contributed almost twice as industry while animal manures contributed significantly within agriculture.