We have investigated the storage and spatial distribution of soil nitrogen (N) in China based on a data set of 2480 soil profiles and a map of Chinese soil types at a spatial resolution of 1:1, 000, 000. Our estimate indicates that the total N storage in China is 8.29 × 1015 g, representing 5.9–8.7% of the total global N storage. The total N storage in China is on average or slightly above the average of its share in the global N storage, even though low nitrogen content soils cover a large area in China. N density varies substantially with soil types and regions. Peat soils in the southeast of Tibet, southwest China, show the highest averaged N density with a value of 7314.9 g/m3 among all soil types. This is more than 30 times of the lowest N density of brown desert soils in the western desert and arid region. The highest N storages among all the soil types are the felty soil in southeast of Tibet, dark-brown earths in northeast China, and red earths in southeast China with values of 921.1, 611.4, and 569.6 Tg, respectively. N density also varies with land cover types in China. Wetlands in southwest China exhibit the highest N density at 6775.9 g/m3 and deserts in northwest China have the least at 447.5 g/m3. Our analysis also indicates that land cover types are poor predictors of N content. Further research is needed to examine how transformation from organic agriculture to increased use of fertilizers and pesticides has influenced N storage in China.

Tian, H., S. Wang, J. Liu, S. Pan, H. Chen, C. Zhang, and X. Shi (2006), Patterns of soil nitrogen storage in China, Global Biogeochem. Cycles, 20, GB1001, doi:10.1029/2005GB002464.