NO and N2O fluxes from agricultural soils in Beijing area.

Chinese agriculture represents one of the most intensively managed agroecosystems in the world. Typical nitrogen fertilization rates are more than three times those of the world' s average, resulting in dramatically accelerated nitrogen cycling in China. In this study, we have examined NO and N2O exchange in the upland agricultural systems of Beijing area. Inorganic and organic fertilizer treatments were arranged in order to evaluate their impact on the magnitude and proportion of trace gas emissions. Increasing inorganic fertilization rates showed a highly significant impact upon emissions of both NO and N2O. Organic matter amendment did not have a statistically significant impact on the N-gas fluxes examined here. Overall losses of added nitrogen by NO and N2O emission averaged 1. 24% and 0. 22% respectively over the range of treatments in this study. Results from our field study indicate that compared with other studies done elsewhere, emissions of reactive nitrogen from agricultural systems in Beijing area are not so large as expected before. [ABSTRACT FROM AUTHOR]