[A review on development of stable isotope technique in the studies of N₂O formation mechanism]

As one of three major greenhouse gases, nitrous oxide (N₂O) has solicited substantial attention. Stable isotope has been widely used to explore the sources of N₂O emissions. Here, we briefly introduced the microbial processes involved in N₂O emissions, and the main influencing factors. We further summarized the development of N₂O isotope signature of δ¹⁵N, δ¹⁸O and SP (site preference of ¹⁵N in different positions of N₂O molecule) in exploring the N₂O formation mechanism. The application of these techniques, especially the SP values, is still at the primary stage in China. Therefore, this paper focused on the development of the isotope ratios analysis in partitioning N₂O sources from foreign countries, and put forward suggestions on the future research in China.