Asynchronous pulse responses of soil carbon and nitrogen mineralization to rewetting events at a short-term:...

Rewetting after precipitation events plays an important role in regulating soil carbon (C) and nitrogen (N) turnover processes in arid and semiarid ecosystems. Here, we conducted a 48-h rewetting simulation experiment with measurements of soil C and N mineralization rates (R _C and R _N, respectively) and microbial biomass N (MBN) at high temporal resolution to explore the pulse responses of R _C and R _N. R _C and R _N responded strongly and rapidly to rewetting over the short term. The maximum R _C value (because of pulse effects) ranged from 16.53 to 19.33 µg C g_soil^-1 h^-1, observed 10 min after rewetting. The maximum R _N varied from 22.86 to 40.87 µg N g_soil^-1 h^-1, appearing 5-6 h after rewetting. The responses of soil microbial growth to rewetting were rapid, and the maximum MBN was observed 2-3 h after rewetting. Unexpectedly, there was no correlation between R _C, R _N, and MBN during the process of rewetting, and R _C and R _N were uncoupled. In sum, the pulse responses of R _C, R _N, and microbial growth to simulated rewetting were rapid, strong, and asynchronous, which offers insights into the different responses of microbes to rewetting and mechanisms behind microbes.