Abstract. Climate change severely impacts the grassland carbon cycling by
altering rates of litter decomposition and soil respiration (Rs),
especially in arid areas. However, little is known about the Rs
responses to different warming magnitudes and watering pulses in situ in desert
steppes. To examine their effects on Rs, we conducted long-term moderate
warming (4 years, ∼3 ∘C), short-term acute
warming (1 year, ∼4 ∘C) and watering field
experiments in a desert grassland of northern China. While experimental
warming significantly reduced average Rs by 32.5 % and 40.8 %
under long-term moderate and short-term acute warming regimes, respectively,
watering pulses (fully irrigating the soil to field capacity) stimulated it
substantially. This indicates that climatic warming constrains soil carbon
release, which is controlled mainly by decreased soil moisture, consequently
influencing soil carbon dynamics. Warming did not change the exponential
relationship between Rs and soil temperature, whereas the relationship
between Rs and soil moisture was better fitted to a sigmoid function.
The belowground biomass, soil nutrition, and microbial biomass were not
significantly affected by either long-term or short-term warming regimes,
respectively. The results of this study highlight the great dependence of
soil carbon emission on warming regimes of different durations and the
important role of precipitation pulses during the growing season in
assessing the terrestrial ecosystem carbon balance and cycle.
Soil carbon release responses to long-term versus short-term climatic warming in an arid ecosystem
