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Soil carbon: sink or source for CO2?

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Soils play an important role in the global carbon cycle, as they store large amounts of carbon and large amounts of carbon dioxide (CO₂) are exchanged between soils and the atmosphere. We are studying the effects of changes in climate and land use on soil carbon storage.

In Switzerland, soils store about 80% of the terrestrial carbon and 7-8 times as much as the atmosphere as CO₂. Temperature, moisture and litter inputs exert a main control on soil carbon cycling. As a consequence, changes in climate and land use affect C fluxes between soils, vegetation, and the atmosphere. In particular, forest disturbances by storms, insects or intense forest exploitation can induce carbon losses from soils.

Key Objectives

How much and in which form is carbon stored in Swiss forest soils?
What are the effects of changes of climate warming, drought and disturbances?
What are the effects of climate change induced vegetation shift on soil carbon?
How does afforestation and management impact soil carbon?
What are the effects of permafrost on the CO₂ balance of alpine soils?

Approaches

Field and lab experiments: Response of C fluxes and pools to increased soil temperatures, drought, elevated CO₂, and N deposition.
Stable isotopes and radiocarbon: tracing carbon in soil pools and fluxes.
Monitoring of fluxes: measuring soil CO2 fluxes and DOC leaching in forests.
Carbon inventory: estimates of C stocks of Swiss forest soils.

FURTHER INFORMATION

Contact

Dr. Frank Hagedorn

Groupleader, Senior Scientist

Forest Soils and Biogeochemistry

Biogeochemistry

frank.hagedorn(at)wslto make life hard for spam bots.ch

+41 44 739 24 63+41 44 739 24 63

Birmensdorf

Publications

Frey, B.; Moser, B.; Tytgat, B.; Zimmermann, S.; Alberti, J.; Biederman, L.A.; Borer, E.T.; Broadbent, A.A.D.; Caldeira, M.C.; Davies, K.F.; Eisenhauer, N.; Eskelinen, A.; Fay, P.A.; Hagedorn, F.; Hautier, Y.; MacDougall, A.S.; McCulley, R.L.; Moore, J.L.; Nepel, M.; ... Risch, A.C., 2023: Long-term N-addition alters the community structure of functionally important N-cycling soil microorganisms across global grasslands. Soil Biology and Biochemistry, 176: 108887 (11 pp.). doi: 10.1016/j.soilbio.2022.108887

Mayer, M.; Rusch, S.; Didion, M.; Baltensweiler, A.; Walthert, L.; Ranft, F.; Rigling, A.; Zimmermann, S.; Hagedorn, F., 2023: Elevation dependent response of soil organic carbon stocks to forest windthrow. Science of the Total Environment, 857: 159694 (9 pp.). doi: 10.1016/j.scitotenv.2022.159694

Klesse, S.; Wohlgemuth, T.; Meusburger, K.; Vitasse, Y.; Von Arx, G.; Lévesque, M.; Neycken, A.; Braun, S.; Dubach, V.; Gessler, A.; Ginzler, C.; Gossner, M.M.; Hagedorn, F.; Queloz, V.; Samblás Vives, E.; Rigling, A.; Frei, E.R., 2022: Long-term soil water limitation and previous tree vigor drive local variability of drought-induced crown dieback in Fagus sylvatica. Science of the Total Environment, 851: 157926 (12 pp.). doi: 10.1016/j.scitotenv.2022.157926

Meusburger, K.; Trotsiuk, V.; Schmidt-Walter, P.; Baltensweiler, A.; Brun, P.; Bernhard, F.; Gharun, M.; Habel, R.; Hagedorn, F.; Köchli, R.; Psomas, A.; Puhlmann, H.; Thimonier, A.; Waldner, P.; Zimmermann, S.; Walthert, L., 2022: Soil–plant interactions modulated water availability of Swiss forests during the 2015 and 2018 droughts. Global Change Biology, 28, 20: 5928-5944. doi: 10.1111/gcb.16332

Fetzer, J.; Frossard, E.; Kaiser, K.; Hagedorn, F., 2022: Leaching of inorganic and organic phosphorus and nitrogen in contrasting beech forest soils – seasonal patterns and effects of fertilization. Biogeosciences, 19, 5: 1527-1546. doi: 10.5194/bg-19-1527-2022

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Projects

Control on soil organic matter in Swiss forests

The cycling of carbon and nitrogen are closely linked and thus, the increasing deposition of nitrogen very likely affects soil organic matter dynamics. We are adding 13C and 15N labeled litter from beech to soils and investigate how experimentally increased N inputs influence the fate of litter-derived C and N.

RICH-SOIL: Radiocarbon Inventory of Swiss Soils

RICH-SOIL gains insight into soil C cycling by determining radiocarbon signatures in Swiss soil C pools and fluxes. The project analyses archived samples, national soil inventory, and the LWF (Long-term-Monitoring of Forests Ecosystem) program.

Carbon cycling in forest floors

The project quantifies carbon fluxes in forest floors along gradients in climate and bedrock in Switzerland and Germany. The approach is to measure radiocarbon contents in C pools and fluxes, and tracing isotopically labelled (13C, 15N, 2H) litter in the FF and in the mineral soil beneath.

Soil organic matter dynamics under drought

DRYSOM assesses soil organic matter (SOM) to drought in a long-term irrigation experiment (Pfynwald). Responses range from a suppressed processing through microbial and faunal communities, decreases in carbon inputs from trees into soils, to shifts in soil carbon storage.

Forest disturbances induce soil carbon losses

Disturbances of forest ecosystems by storms and dieback following drought and insect infestation are increasing with ongoing climatic changes. We study the magnitude of C losses following disturbances by combining field studies, modelling, and a meta-analysis.

The role of mycorrhizae in soil carbon storage of mountain ecosystems

This research project focuses on the role of mycorrhizae in the turnover of soil organic carbon in mountain ecosystems. It estimates the potential release of greenhouse gases to the atmosphere resulting from changes in above and belowground communities.

ExtremeThaw

In this ambitious project, we study ecological effects of permafrost thaw in the Swiss Alps.

Forest soil inventory

The repetition of the forest soil inventory provides the basis for representative forest soil monitoring throughout Switzerland. Through the connection to the sampling network of the National Forest Inventory, a variety of possibilities for the use and evaluation of the collected soil data are possible.

Establishing hydrogen isotope analysis of organic material

We aim to develop a method for hydrogen isotope (d2H) analysis of organics which will have many applications in plant and soil sciences and thereby provide a powerful new tool to disentangle and reconstruct past and present physiological, biochemical, and hydrological processes.

Root endophytic fungi and their contribution to arctic and alpine climate change feedback

Arctic and Alpine vegetation dynamics under climate change can exert a lasting impact on belowground processes and ultimately on world's largest carbon stocks. This long-term field manipulation investigates the functional significance of plant interactions with species-specific endophytic fungi.

Abisko Long-Term Ecological Research ALTER

Setting up the ALTER experiment in Abisko, Sweden for non-destructive in situ monitoring of belowground vegetation and microbial dynamics.

Treeline in Ural

Historical photographs document that the upper treeline of the Ural mountains has moved up 60 to 80 m during the last century. We assess how the expansion of forests into tundra affects soil organic matter dynamics in the pristine Southern, Northern and Polar Ural.