SNS-funded team has prepared recommendations for what to consider when studying greenhouse gas exchange of drained organic forest soils.
Text: Jyrki Jauhiainen and Raija Laiho
The Nordic and Baltic countries are rich in organic soils, which are hotspots of soil carbon. These are mainly peat soils, but there are also other types of wetland soils rich in organic matter, like gleysols. Over time, large areas of organic soils have been drained for agriculture and forestry. Their carbon stores are currently of great interest, since we wish to keep the soil carbon in the soils to combat climate change.
Drained organic forest soils in boreal and temperate climate zones are believed to be significant sources of carbon dioxide (CO2), methane (CH4) and nitrous oxide (N2O), but the annual fluxes are still highly uncertain. Drained organic soils exemplify systems where many greenhouse gas (GHG) flux monitoring studies are still carried out with relatively small resources, several methodologies and manually operated systems, which further involve different options for the detailed design of the measurement and data analysis protocols for deriving the annual flux.
Collated peer-reviewed publications
We collated peer-reviewed publications presenting GHG flux data for drained organic forest soils in boreal and temperate climate zones, focusing on data that have been used, or have the potential to be used, for estimating net annual soil GHG emission/removals. We evaluated the methods used in data collection, and identified major gaps in background/environmental data. It became clear that (i) each data collection method and data type has its strengths and weaknesses that contribute to the final outcome when converted to soil GHG balance estimates, and (ii) it would be highly beneficial to consider post-publication data use already during reporting by providing details on site characteristics and conditions, relatively easily acquirable measurements that have potential to correlate with GHG fluxes.
Based on the analysis we developed suggestions for future data collection for how to measure and report the data, so that data from individual studies could also be used in synthesis work based on data collation and modelling. Such synthesis work is necessary for deciphering general patterns and trends related to, e.g., site types, climate, and management, and the development of corresponding emission factors, i.e., estimates of the net annual soil GHG emission/removal, which can be used in GHG inventories.
Citation: Jauhiainen J., Alm J., Bjarnadottir B., Callesen I., Christiansen J.R., Clarke N., Dalsgaard L., He H., Jordan S., Kazanavičiūtė V., Klemedtsson L., Lauren A., Lazdins A., Lehtonen A., Lohila A., Lupikis A., Mander Ü, Minkkinen K., Kasimir Å., Olsson M., Ojanen P., Óskarsson H., Sigurdsson B.D., Søgaard G., Soosaar K., Vesterdal L. & Laiho R. 2019. Greenhouse gas exchange data from drained organic forest soils – a review of current approaches and recommendations for future research. Biogeosciences 16: 4687-4703. https://doi.org/10.5194/bg-16-4687-2019