Long‐term manipulation of mean climatic conditions alters drought effects on C‐ and N‐cycling in an arable soil. (8th April 2022)

• Record Type: Journal Article
• Authors: Leyrer, Vinzent; Patulla, Marina; Hartung, Jens; Marhan, Sven; Poll, Christian
• Is Part Of: Global change biology. Volume 28:Number 12(2022)
• Page Start: 3974
• Page End: 3990
• Publication Date: 2022-04-08
• Subjects: climate change -- drought stress -- legacy effect -- soil gas fluxes -- soil microorganisms -- temperate agroecosystem; Climatic changes -- Environmental aspects -- Periodicals; Troposphere -- Environmental aspects -- Periodicals; Biodiversity conservation -- Periodicals; Eutrophication -- Periodicals; 551.5
• DOI: 10.1111/gcb.16173
• Languages: English
• ISSNs: 1354-1013

Abstract

Abstract: Climate is changing and predicted future scenarios include both changes in long‐term mean climatic conditions and intensification of extreme events such as drought. Drought can have a major impact on soil functional processes; soil microorganisms, key to these processes, depend on water and temperature dynamics. Consequently, feedback mechanisms regarding microbially mediated carbon and nitrogen cycling in soils may be affected. There are indications that microbial exposure to increasingly unfavorable environmental conditions influences their stress responses. Here, the long‐term field experiment Hohenheim Climate Change (HoCC) provided a research platform to explore how microbial exposure to long‐term reduced water availability and soil warming modifies microbially driven soil processes, especially gas fluxes from soil, both during drought and after rewetting. The HoCC experiment is an agroecosystem in which the soil microbiome has been exposed to reduced annual mean precipitation and elevated temperature since 2008. Treatment levels were chosen based on a realistic future climate scenario. In June 2019, we exposed this system to a drought period of four weeks. We found that even after 11 years, warming remained a driver of CO2 and N2 O fluxes across the different soil moisture conditions in our drought experiment. Importantly, however, microbial exposure to long‐term reduced water availability limited the stimulatory effect of warming on gas fluxes during drought and after rewetting. Our results were neither related to a legacy effect within overall microbial biomass carbon levels nor a shift towards enhanced fungal abundance. We found no indications that extracellular enzyme activities or microbial substrate availability explained the gas flux dynamics observed in our drought experiment. Our study indicates that soil warming promotes gaseous C and N loss even under extreme drought conditions. We suspect, however, that a shift in microbial function following long‐term water limitation can hamper the enhancing effect of warming on soil gas fluxes. Abstract : Climate is changing in mean conditions and intensification of extreme events. A microbiome exposed to a decade of reduced precipitation and elevated temperatures changes in its response to extreme events of drought and rewetting. In detail, seasonally reducing the precipitation amount limited the enhancing effect of warming on CO2 /N2 O fluxes during drought and after rewetting. We could neither connect this legacy effect to overall microbial nor fungal abundance in specific. Also, substrate availability and enzyme activities could not explain our observations. Estimations of Q 10 indicate that gas flux patterns may have been driven by changes in microbial physiological traits.