Soil microbial fluctuation and CO release increase under dry-wet cycles

Suzuki, Yuri*; Nagano, Hirohiko*; Hiradate, Shuntaro*; Atarashi-Andoh, Mariko  ; Abe, Yukiko; Koarashi, Jun   ; Nakayama, Masataka  

Recently, precipitation patterns are changing to less frequent events but stronger intensities with the progress of global warming. Such changes in precipitation raise concerns about increasing dry-wet cycles and CO release in soil. However, the mechanisms of soil CO release increase by dry-wet cycles are still unclear. In our soil incubation experiment for ten soils, dry-wet cycles significantly increased the CO release rate for all soils. Microbial biomass for all soils were significantly lower under the dry-wet cycles than under the constant moisture conditions. Quantitative PCR showed that fungal DNA concentrations were significantly lower under the dry-wet cycles. These results may suggest that the CO release increase is associated with soil microbial fluctuations caused by the dry-wet cycles.