Abstract. 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 kg N ha−1 yr−1). Although Rs was found to show
a unimodal change pattern with the variation of soil moisture, soil
temperature and soil NH4+-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.
Peer Review #2 of "Life history response of Echinops gmelinii Turcz. to variation in the rainfall pattern in a temperate desert (v0.3)"
