Abstract:Atmospheric N deposition and their N sources in Chongren County were investigated on the basis of the nitrogen concentrations and nitrogen isotope in mosses, which were collected from 10 towns during 2009~2010. Nitrogen concentrations in mosses ranged from 2.24% to 3.43% and showed a significant regional difference. The highest N concentrations (N>3%) were found in Guoxu and Lipi Towns, where agricultural activity is strong. The level of atmospheric N deposition in the county was calculated according to the quantitative relationship between moss N concentration and atmospheric N deposition. The level of atmospheric N deposition ranged between 29.62~54.39 kg/(hm2·a), showed that atmospheric nitrogen deposition was an important N input in rural areas. The d15N values in mosses varied from -3.11‰ to 0.078‰, indicative of the large contribution of NH3 emission sources connected with fertilizer application. The moss d15N values (-1.7‰) in Chongren County suggested that atmospheric N deposition was also influenced by the city excretory wastes and sewage NH3 emission. The moss d15N values in Sunfang Town were in the range of-5.89‰~0.61‰, associated with the extensive NH3 emission from landfill.