Methane fluxes but not respiratory carbon dioxide fluxes altered under Si amendment during drying – rewetting cycles in fen peat mesocosms

Hömberg, Annkathrin; Broder, Tanja; Schaller, Jörg; Knorr, Klaus‐Holger

doi:10.1016/j.geoderma.2021.115338

Cited by 7 publications

(3 citation statements)

References 49 publications

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“…The large response variation of the Si effect on the soil-CO 2 production rate (from increasing to decreasing) is in contrast to previous studies, reporting a positive effect of Si on soil respiration or organic-matter decomposition (Schaller et al, 2014;Marxen et al, 2015;Schaller et al, 2019). The effect of Si addition increased the soil-CO 2 production rate and might be explained by the silicic acid increasing both the soil phosphorus and soil's organic matter availability for microbial decomposers (Reithmaier et al, 2017;Schaller et al, 2019;Hömberg et al, 2020;Hömberg et al, 2021b). Polysilicic acid is competing with both dissolved organic carbon and phosphate for sorption sites at the surface of soil particles (Schaller et al, 2019;Hömberg et al, 2020;Schaller et al, 2021), mostly iron oxidic phases.…”

Section: Discussioncontrasting

confidence: 69%

“…Polysilicic acid is competing with both dissolved organic carbon and phosphate for sorption sites at the surface of soil particles (Schaller et al, 2019;Hömberg et al, 2020;Schaller et al, 2021), mostly iron oxidic phases. The subsequent higher availability of both organic carbon and phosphate may result in an increase of greenhouse gas production by accelerating soil respiration afterward (Reithmaier et al, 2017;Schaller et al, 2019;Hömberg et al, 2021b;Hömberg et al, 2021c). A decreasing effect of Si on soil-CO 2 production rates was observed especially under waterlogged conditions.…”

Section: Discussionmentioning

confidence: 96%

“…Asi in soils can reduce hydraulic conductivity near saturation, increase hydraulic conductivity in dry soils, and is the main source of silicic acid (Schaller et al, 2020;Schaller et al, 2021). With this reduction in hydraulic conductivity near saturation, Asi may reduce the availability of electron acceptors leading to potentially more reduced conditions (Hömberg et al, 2021a;Hömberg et al, 2021b). Silicic acid competes with nutrients such as P and C org for binding at the surface of iron minerals (Schaller et al, 2019;Hömberg et al, 2020).…”

Section: Introductionmentioning

confidence: 99%

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The importance of calcium and amorphous silica for arctic soil CO2 production

Stimmler

Göckede

Natali

et al. 2022

Front. Environ. Sci.

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Future warming of the Arctic not only threatens to destabilize the enormous pool of organic carbon accumulated in permafrost soils but may also mobilize elements such as calcium (Ca) or silicon (Si). While for Greenlandic soils, it was recently shown that both elements may have a strong effect on carbon dioxide (CO2) production with Ca strongly decreasing and Si increasing CO2 production, little is known about the effects of Si and Ca on carbon cycle processes in soils from Siberia, the Canadian Shield, or Alaska. In this study, we incubated five different soils (rich organic soil from the Canadian Shield and from Siberia (one from the top and one from the deeper soil layer) and one acidic and one non-acidic soil from Alaska) for 6 months under both drained and waterlogged conditions and at different Ca and amorphous Si (ASi) concentrations. Our results show a strong decrease in soil CO2 production for all soils under both drained and waterlogged conditions with increasing Ca concentrations. The ASi effect was not clear across the different soils used, with soil CO2 production increasing, decreasing, or not being significantly affected depending on the soil type and if the soils were initially drained or waterlogged. We found no methane production in any of the soils regardless of treatment. Taking into account the predicted change in Si and Ca availability under a future warmer Arctic climate, the associated fertilization effects would imply potentially lower greenhouse gas production from Siberia and slightly increased greenhouse gas emissions from the Canadian Shield. Including Ca as a controlling factor for Arctic soil CO2 production rates may, therefore, reduces uncertainties in modeling future scenarios on how Arctic regions may respond to climate change.

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