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Soil respiration (Rs/ is the most important source of carbon dioxide emissions from soil to atmosphere. However, it is unclear what the interactive response of Rs would be to environmental changes such as elevated precipitation, nitrogen (N) deposition and warming, especially in unique temperate desert ecosystems. To investigate this an in situ field experiment was conducted in the Gurbantunggut Desert, northwest China, from September 2014 to October 2016. The results showed that precipitation and N deposition significantly increased Rs, but warming decreased Rs, except in extreme precipitation events, which was mainly through its impact on the variation of soil moisture at 5 cm depth. In addition, the interactive response of Rs to combinations of the factors was much less than that of any single-factor and the main response was a positive effect, except for the response from the interaction of increased precipitation and high N deposition (60 kgNha-1 yr-1/. Although Rs was found to show a unimodal change pattern with the variation of soil moisture, soil temperature and soil NHC 4 -N content and it was significantly positively correlated to soil dissolved organic carbon (DOC) and pH, a structural equation model found that soil temperature was the most important controlling factor. Those results indicated that Rs was mainly interactively controlled by the soil multi-environmental factors and soil nutrients and was very sensitive to elevated precipitation, N deposition and warming. However, the interactions of multiple factors largely reduced between-year variation of Rs more than any single-factor, suggesting that the carbon cycle in temperate deserts could be profoundly influenced by positive carbon-climate feedback. [ABSTRACT FROM AUTHOR]

Abstract An experiment was conducted to investigate the effect of precipitation and N deposition on N 2 O and CH 4 fluxes and soil respiration (R s) in the Gurbantunggut Desert from September 2014 to August 2015. The desert was a weak sink for CH 4 (−0.92 kg C ha−1 yr−1) and a small source of N 2 O (+0.13 kg N ha−1 yr−1) and the annual rate of R s was 874 kg C ha−1. Our work confirmed a relatively strong sink for CH 4 in desert soils. Significant impacts on N 2 O, CH 4 fluxes and R s were found by increasing precipitation, with pulses of CH 4 uptake and R s accounting for 79.1% and 33.2% of annual CH 4 uptake and R s , respectively. N 2 O and CH 4 fluxes were significantly enhanced by 7.8–109.6% by N addition, but it had no significant effect on R s. Statistical significant interactions of precipitation and N addition on N 2 O and CH 4 fluxes were found, and on R s was lower than any single factor. Our results indicate that the Gurbantunggut Desert is a weak sink for CH 4 and a small source of N 2 O, and is sensitive to elevated precipitation and N deposition. Highlights • The Gurbantunggut Desert was a weak sink for CH 4 and source of N 2 O. • N 2 O and CH 4 fluxes were significantly increased by precipitation and N deposition. • Significant interactive effects of water and N on N 2 O and CH 4 fluxes were found. • Interactive effects of water and N on soil respiration were lower than any single factor. [ABSTRACT FROM AUTHOR]