POSTER: Soil microbial responses to extreme weather and land-use management across a Swedish precipitation gradient

Description

Extreme weather together with land-use management strongly impact soil microbial communities, where drought and rainfall cycles release carbon dioxide from the soil, and the soil structure determines the soil’s water and air availability. Understanding the combined effect of drying-rewetting and soil
structure on microbial processes is therefore important to forecast future changes to the terrestrial carbon cycle. To investigate the microbial growth and respiration responses to drying-rewetting after soil structure disturbance, we selected 11 grassland sites across a precipitation gradient in Sweden ranging
between 400-1200 mm/year. We explored undisturbed and disturbed soil structure by both grinding soils in the laboratory and by in situ tillage along this gradient. We expected that microorganisms in dryer sites, exposed to more drought cycles, would exhibit faster growth and lower respiration after rewetting. We also expected that disruption of soil structure would exacerbate the severity of the drought cycle, thus slower growth and increased respiration. Surprisingly, results show that disrupting the structure accelerated microbial growth after rewetting but the respiration was unaffected compared to undisturbed soil, resulting in an increased carbon use efficiency. The carbon use efficiency also increased in wetter sites, meaning the microbial community carbon-budget shifted from atmospheric release to soil storage.

Period	2022 May 17
Event title	Swedish Climate Symposium 2022
Event type	Conference
Location	Norrköping, SwedenShow on map