Are annual nitrous oxide fluxes sensitive to warming and increasing precipitation in the Gurbantunggut Desert?

Abstract

AbstractTemperate desert soils are an important source of atmospheric nitrous oxide (N2O). However, it is uncertain how N2O emissions respond to warming, increased rainfall and nitrogen (N) addition in such soils. A multifactorial field manipulation study was carried out in the Gurbantunggut Desert, China's second largest desert, to investigate how these factors influence desert soil N2O emissions and to assess inter‐year variation. In our 3‐year study, under current climatic conditions, the annual flux of N2O in this temperate desert soil was 0.13 ± 0.02 kg N ha−1 yr−1, with the period of no plant growth contributing 43% of the annual emission. Surprisingly, there was no significant change in annual N2O flux under warming (+1°C) or increased precipitation (30%, +60 mm yr−1). In contrast, N2O emissions were significantly affected by extreme drought followed by precipitation. Additional N input, at 30 or 60 kg N ha−1 yr−1, greatly elevated annual N2O emission by 55–133%. The combined impact of N deposition and increasing rainfall on N2O emission was greater than that of any single factor, except for N deposition. This suggests that N2O emissions in this desert are driven primarily by soil available N content and are less sensitive to variations in soil temperature and moisture.