High emissions of greenhouse gases from grasslands on peat and other organic soils

verfasst von

Bärbel Tiemeyer, Elisa Albiac Borraz, Jürgen Augustin, Michel Bechtold, Sascha Beetz, Colja Beyer, Matthias Drösler, Martin Ebli, Tim Eickenscheidt, Sabine Fiedler, Christoph Förster, Annette Freibauer, Michael Giebels, Stephan Glatzel, Jan Heinichen, Mathias Hoffmann, Heinrich Höper, Gerald Jurasinski, Katharina Leiber-Sauheitl, Mandy Peichl-Brak, Niko Roßkopf, Michael Sommer, Jutta Zeitz

Abstract

Drainage has turned peatlands from a carbon sink into one of the world's largest greenhouse gas (GHG) sources from cultivated soils. We analyzed a unique data set (12 peatlands, 48 sites and 122 annual budgets) of mainly unpublished GHG emissions from grasslands on bog and fen peat as well as other soils rich in soil organic carbon (SOC) in Germany. Emissions and environmental variables were measured with identical methods. Site-averaged GHG budgets were surprisingly variable (29.2 ± 17.4 t CO₂-eq. ha⁻¹ yr⁻¹) and partially higher than all published data and the IPCC default emission factors for GHG inventories. Generally, CO₂ (27.7 ± 17.3 t CO₂ ha⁻¹ yr⁻¹) dominated the GHG budget. Nitrous oxide (2.3 ± 2.4 kg N₂O-N ha⁻¹ yr⁻¹) and methane emissions (30.8 ± 69.8 kg CH₄-C ha⁻¹ yr⁻¹) were lower than expected except for CH₄ emissions from nutrient-poor acidic sites. At single peatlands, CO₂ emissions clearly increased with deeper mean water table depth (WTD), but there was no general dependency of CO₂ on WTD for the complete data set. Thus, regionalization of CO₂ emissions by WTD only will remain uncertain. WTD dynamics explained some of the differences between peatlands as sites which became very dry during summer showed lower emissions. We introduced the aerated nitrogen stock (N_air) as a variable combining soil nitrogen stocks with WTD. CO₂ increased with N_air across peatlands. Soils with comparatively low SOC concentrations showed as high CO₂ emissions as true peat soils because N_air was similar. N₂O emissions were controlled by the WTD dynamics and the nitrogen content of the topsoil. CH₄ emissions can be well described by WTD and ponding duration during summer. Our results can help both to improve GHG emission reporting and to prioritize and plan emission reduction measures for peat and similar soils at different scales.

Externe Organisation(en)

Johann Heinrich von Thünen-Institut, Bundesforschungsinstitut für Ländliche Räume, Wald und Fischerei
Leibniz-Zentrum für Agrarlandschaftsforschung (ZALF) e.V.
Universität Rostock
Landesamt für Bergbau, Energie und Geologie (LBEG)
Hochschule Weihenstephan-Triesdorf
Johannes Gutenberg-Universität Mainz
Technische Universität München (TUM)
Universität Hohenheim
Meo Carbon Solutions GmbH
Universität Wien
Humboldt-Universität zu Berlin
Landesamt für Bergbau, Geologie und Rohstoffe Brandenburg (LBGR)

Typ

Artikel

Journal

Global change biology

Band

22

Seiten

4134-4149

Anzahl der Seiten

16

ISSN

1354-1013

Publikationsdatum

12.2016

Publikationsstatus

Veröffentlicht

Peer-reviewed

Ja

ASJC Scopus Sachgebiete

Globaler Wandel, Umweltchemie, Ökologie, Umweltwissenschaften (insg.)

Ziele für nachhaltige Entwicklung

SDG 13 – Klimaschutzmaßnahmen

Elektronische Version(en)

https://doi.org/10.1111/gcb.13303 (Zugang: Geschlossen)