Carbon content and other soil properties of near-surface peats before and after peatland restoration

Jenny Hammerich; Corinna Schulz; Robert Probst; Thomas Lüdicke; Vera Luthardt

doi:10.7717/peerj.17113

Carbon content and other soil properties of near-surface peats before and after peatland restoration

PeerJ. 2024 Apr 18:12:e17113. doi: 10.7717/peerj.17113. eCollection 2024.

Authors

Jenny Hammerich^{1

2}, Corinna Schulz^{1

3}, Robert Probst¹, Thomas Lüdicke⁴, Vera Luthardt¹

Affiliations

¹ Faculty of Landscape Management & Nature Conservation, Eberswalde University for Sustainable Development, Eberswalde, Brandenburg, Germany.
² Center of Methods & Faculty of Sustainability, Leuphana University, Lüneburg, Lower Saxony, Germany.
³ Institute of Botany and Landscape Ecology, Greifswald University, Greifswald, Mecklenburg-Western Pomerania, Germany.
⁴ UWEG Engineers & Analytics GmbH, Eberswalde, Brandenburg, Germany.

Abstract

Peatland restoration usually aims at restarting the peatlands' function to store carbon within peat. The soil properties of the near-surface peat can give a first understanding of this process. Therefore, we sampled pH value, total organic carbon content (TOC), total nitrogen content (TN), C/N ratio as well as dry bulk density (BD), and describe the structure of near-surface peats in six restored fens in North-East Germany before (2002-2004) and after (2019-2021) restoration. Before restoration, the study sites showed peat degradation to various extents in their near-surface peats. pH values remained relatively stable over time. Comparing the degraded peat horizons, TOC increased significantly in four study sites, ranging from 35.7% to 47.8% in 2002-2004 and from 42.5% to 54.0% in 2019-2021. TN varied from 1.5% to 3.5% in 2002-2004 and from 1.8% to 3.2% in 2019-2021, but changes were only significant in one site, showing a slight decrease. In three sites, the increase in C/N ratio was significant, indicating lower nutrient availability. BD ranged from 0.08 to 0.48 g/cm³ in 2002-2004 and from 0.10 to 0.16 g/cm³ in 2019-2021, decreasing significantly in four sites. The structure of the degraded peat horizons changed after restoration to a more homogenous, sludge mass with larger re-aggregates. In three sites, new peat moss peat layers above the degraded soil horizon were present in 2019-2021, with a mean thickness of 6.8 to 36.1 cm. The structure was comparable to typical, slightly decomposed peat moss peat. Our findings suggest that within about 17 years after fen restoration, and thereby a water table rise close to surface, TOC of the near-surface peats increased to values that are typical for undisturbed peatlands. This indicates that restoration can lead to the re-establishment of peatlands as potential carbon sinks, with TOC within the near-surface peat as one key factor in this process. Further, we assume that the decrease in nutrient availability, decrease of BD, and new, undisturbed peat layers can favor the establishment of mire-specific biodiversity and support ecosystem services similar to near-natural mires.

Keywords: C/N ratio; Dry bulk density; Mire; Nitrogen content; Rewetting; pH value.

Publication types

Research Support, Non-U.S. Gov't

MeSH terms

Carbon* / analysis
Environmental Restoration and Remediation
Germany
Hydrogen-Ion Concentration
Nitrogen* / analysis
Soil* / chemistry
Wetlands*

Substances

Soil
Carbon
Nitrogen

Grants and funding

This work was supported by the State Environmental Agency of Brandenburg. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.