Measurements of atmospheric N_2O concentration and its emission fluxes from soil in China

摘要

Air samples in China were collected and determined for the concentration of N_2O. The production rates of N_2O from agricultural soils were measured with the chamber method. The results indicate that the background concentration of N_2O averages (308 ± 5) x 10~(-9) in 1989, which is close to that obtained at the other background stations abroad. However, at both urban and rural areas, atmospheric N_2O concentrations are higher. N_2O emission fluxes from several farmlands are different and dependent on the factors of agricultural practice and climate. But their magnitudes are at the same order. Preliminary calculation shows that the released N_2O-N from agricultural sources (cultivated soil and N-fertilizers) amounts to 122 Gg/a in China in 1990.