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Keywords:

  • anthropogenic activity;
  • emission inventory;
  • reactive gases;
  • rural catchment

Abstract

To evaluate the atmospheric load of reactive gaseous nitrogen in the fast-developing Eastern China region, we compiled inventories of nitrous oxide (N2O), nitrogen oxide (NOx) and ammonia (NH3) emissions from a typical rural catchment in Jiangsu province, China, situated at the lower reach of the Yangtze River. We considered emissions from synthetic N fertilizer, human and livestock excreta, decomposition of crop residue returned to cropland and residue burning, soil background and household energy consumption. The results showed that, for the 45.5 km2 catchment, the annual reactive gaseous emission was 279 ton N, of which 7% was N2O, 16% was NOx and 77% was NH3. Synthetic N fertilizer application was the dominant source of N2O and NH3 emissions and crop residue burning was the dominant source of NOx emission. Sixty-seven percent of the total reactive gaseous N was emitted from croplands, but on a per unit area basis, NOx and NH3 emissions in residential areas were higher than in croplands, probably as a result of household crop residue burning and extensive human and livestock excreta management systems. Emission per capita was estimated to be 18.2 kg N year−1 in the rural catchment, and emission per unit area was 56.9 kg N ha−1year−1 for NH3 + NOx, which supports the observed high atmospheric N deposition in the catchment. Apparently, efficient use of N fertilizer and biological utilization of crop straw are important measures to reduce reactive gases emissions in this rural catchment.