The UK Climate Change Committee (CCC) has set a target to increase the area of peatlands in good condition to 55% by 2050 through restoration and improved management. However, due to limited data, it remains uncertain how much greenhouse gas a restored peatland emits or sequesters over time, making these interventions difficult to assess.

Northern Ireland has a peat soil coverage of about 242,600 ha, representing approximately 18% of its land area. Around two-thirds consists of semi-natural peatlands, defined as areas that have experienced some human intervention (like grazing and drainage) while retaining natural peatland characteristics. The total greenhouse gas emission from peatlands in Northern Ireland were previously estimated at around 2,232 kt CO2e (Evans et al., 2017), representing 10% of Northern Ireland's total emission. However, some emissions were estimated using the IPCC’s emission factors (Wetlands Supplement, 2013), which may not represent the specific character of peatland in Northern Ireland.

To develop better estimates for Northern Ireland and reduce uncertainty, we measured CO₂ and CH₄ fluxes to create carbon and greenhouse gas budgets for four semi-natural peat bogs using the eddy covariance method between 2022 and 2024. These sites represent different degrees of human intervention, including a grazed blanket bog, two relatively natural raised bogs with some hydrological intervention, and a recently restored raised bog. Our results show that the IPCC Tier 1 emission factors tend to overestimate the emissions from peatlands in Northern Ireland. In fact, on average, these sites appear to function as net carbon and greenhouse gas  sinks, with the grazed blanket bog showing the highest uptake. Here, we present results from these sites, and a discussion on the temporal and spatial dynamics of peatland carbon fluxes.

How to cite: van den Berg, M., Riutta, T., Reeve, E., Thompson, H., Cumming, A., Jovani, J., Oakley, S., Cooper, H., Evans, C., Jordan, P., D'Acunha, B., Bodo, A., and Morrison, R.: Greenhouse gas balance for peat bogs in Northern-Ireland: moving towards Tier 2 emission factors using distributed eddy covariance measurements, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-11779, https://doi.org/10.5194/egusphere-egu25-11779, 2025.

Peatlands are the largest terrestrial carbon stores on earth and play a significant role in the global carbon cycle. They become major sources of carbon when drained and degraded through unsustainable management like peat extraction, drainage, and conversion to agriculture and forestry. Restoration through rewetting—such as ditch blocking and bund construction—has been identified as one of the most efficient methods to accelerate biodiversity recovery while lowering carbon emissions and increasing carbon uptake. Since 2021, restoration efforts constructing contoured peat embankments (bunds) have been underway at a raised bog previously drained for horticulture extraction in Ireland. We investigated the net ecosystem exchange (NEE) and methane (CH₄) emissions using an Eddy Covariance (EC) system to assess the impacts of restoration on carbon dynamics, with results over a four-year period  indicating the site is still emitting carbon after restoration efforts. However, the restored bog comprises a mosaic of land cover types including bare and vegetated peat, open water and bunds and the spatial variation in soil respiration (Rs) across the site remained unknown. To address this, a chamber-based spatial Rs measurement campaign was carried out over a 10-month period. Unmanned Aerial Vehicle (UAV) surveys were also carried out to quantify land cover at the site. Initial findings revealed that the mean CO₂ efflux from bare peat and bund were 33.45 ± 2.73 (±SEM), and 60.43 ± 5.61 µmol CO₂ m² h⁻¹, respectively, 1-2 years post-restoration work. The study investigated the relationship of Rs with the explanatory factors such as soil temperature (Ts), soil moisture (Ms), and water-table height (Wt). The correlation analysis showed that in the bund areas, Ts exhibited a positive moderate influence on the Rs, while Wt significantly influence Rs in the bare peat areas. This chamber measurements approach spatially will help us to gain the deeper understanding of carbon dynamics in the restored peatland. It will allow us to capture the variations in carbon flux across the site’s various microtopographic features, which provide valuable insights for refining peatland restoration strategies and design methods to mitigate climate change mitigation effectively.

How to cite: Naughton, O., Shamsuzzaman, M., Regan, S., O'Connor, M., Casey, I., and McCarthy, U.: Understanding Carbon Emissions in a Drained Peatland Undergoing Restoration: Insights from Chamber-Based Measurements, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-18864, https://doi.org/10.5194/egusphere-egu25-18864, 2025.

How to cite: Tenhovirta, S., Schindler, T., Mander, Ü., Espenberg, M., Truupõld, J., Kamil-Sardar, M., and Soosaar, K.: CO2, CH4 and N2O balances of restored forestry-drained and natural peatlands in Estonia , EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-9657, https://doi.org/10.5194/egusphere-egu25-9657, 2025.

Wet fen meadows are a traditional form of land use that is nowadays mainly preserved through nature conservation measures. Recent discussions suggest that this land use may also be considered as a form of paludiculture (that is, wet peatland use with the preservation of the peat body). However, the climate effect of this land use type is largely unknown. My presentation shows a complete two-year greenhouse gas (GHG) balance of two previously unexplored, long-term rewetted fens under a nature conservation management regime resulting from biweekly chamber measurements of GHG fluxes at two north-east German sites with acute sedge and at one site with creeping bentgrass from 2014 to 2016. Including harvest and dissolved carbon export, the three sites emitted between 10.4 and 16.3 t CO₂-eq ha^-1 yr^-1, with mean annual water levels between -10 and -19 cm. Emissions consisted mainly of CO₂ uptake and release and were influenced by harvest time and frequency as well as inundation periods during vegetation growth. In addition, CH₄ emissions contributed to the net GHG balance at two sites due to inundation in late summer 2014. N₂O emissions were of minor importance at all three sites. The presentation demonstrates that, depending on proper water management, nature conservation-managed fen meadows can have a similar climate effect as other fen paludicultures, with a GHG mitigation potential of between 15 and 20 t CO₂-eq ha^- 1 yr^-1 compared to drainage-based grassland use on fens. 

How to cite: Wolf, R.: Managing wet fen meadows for nature conservation leads to a moderate warming effect, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-1354, https://doi.org/10.5194/egusphere-egu25-1354, 2025.

Peatlands are globally significant ecosystems with high organic carbon storage capacity due to slow litter decomposition in water-saturated soils promoting anoxic conditions. However, these ecosystems are increasingly threatened by climate change and land-use pressures. In the Pyrenees, mountain peatlands have become relict ecosystems, reduced to small isolated areas of just over one hectare. There, hydrological conditions and vegetation cover are severely impacted by rising temperatures, reduced water availability, and intense livestock activity from large animals (i.e. horses and cows). Effective management strategies to mitigate potential large greenhouse gas (GHG) emissions from these ecosystems are urgently needed.

The ALFAwetlands and Pyrepeat projects investigate the effects of grazing exclusion (i.e. enclosures installed in 2016) and hydrological variation (i.e. strong seasonality) on GHG fluxes in two Pyrenean peatlands, Rubió (42.41º N, 1.24º E) and Estanyeres (42.61º N, 1.05º E). Both peatlands are characterized by contrasting pH (5.97 ± 0.08 and 7.78 ± 0.21, respectively) and water saturation levels. Over two years, monthly measurements of carbon dioxide (CO₂), methane (CH₄), and nitrous oxide (N₂O) emissions were conducted across three plot types outside and within grazing exclusion zones: (1) low livestock trampling and soil disturbance, with barely vegetation gaps (mosses and sedges species); (2) pugged soils with wide exposed peat areas increasing CO₂ oxidation potential, and large vegetation gaps; (3) peatland margin areas with the driest condition, rarely flooded, and continuous vegetation cover of grass-like plants. Within the enclosure, these three types of plot were identified before fences were installed and nowadays they are partially recovered.

Preliminary results highlight the vulnerability of these ecosystems to climatic changes. CO₂ emissions were highest in dry plots of both peatlands, where reduced water content accelerated organic carbon oxidation. In the drier peatland, emissions were further amplified outside exclusion zones. CH₄ emissions were higher in the wetter peatland, consistent with anaerobic conditions that promote methanogenesis, while N₂O emissions remained consistently low across both sites due to nitrogen limitation.

These findings emphasize that climate-driven drying poses a significant threat to peatlands by increasing CO₂ emissions, a risk that is exacerbated by livestock disturbances. Management actions such as grazing exclusion are critical to maintain peatlands’ carbon storage capacity and mitigate GHG emissions from these vulnerable ecosystems. This research contributes to the growing body of knowledge needed to align peatland conservation and restoration with climate change adaptation.

How to cite: Poblador, S., Escarmena, L., Bautista-Medina, B., Grundeus, A., Martinez-Amigo, V., Anaya, I., Ninot, J. M., Pérez-Haase, A., and Sabater, F.: Carbon Under Threat: Insights from Grazing Exclusion and Climate Impacts in Pyrenean high mountain peatlands, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-13008, https://doi.org/10.5194/egusphere-egu25-13008, 2025.

How to cite: Ring-Hrubesh, F., Eberle, A., Gallego-Sala, A., Welch, B., Pancost, R., Griffiths, R., and Bryce, C.: Legacy of peatland erosion continues to shape microbial communities during recovery. , EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-18923, https://doi.org/10.5194/egusphere-egu25-18923, 2025.

Peatlands host the largest store of terrestrial carbon on Earth and it is widely accepted that reversal of their widespread degradation is required to meet emissions targets. Thus, significant action is underway globally to encourage their rewetting and restoration. However, restoration success can be complicated by geological factors in the local environment. Peatlands in regions with iron sulphide-rich rocks and sediments experience drastic drops in pH following drainage and release high concentrations of iron and toxic metals. Accumulation of iron and sulphur in the peat during this time will fundamentally alter biogeochemical cycling, yet we have little understanding of the extent to which these effects can be reversed following the raising of water tables. Furthermore, the long-term impacts on resident microbial communities responsible for dictating the nature and scale of green-house gas emissions from such sites is unknown.

We have compared two neighbouring fens in southern England underlain by glauconite- and pyrite-rich sandstone which are within the same hydrological regime but have experienced differing degrees of historical drainage and degradation. Both fens were designated for conservation and rewetted in the 1970s. Porewater nutrient and greenhouse gas profiles, peat geochemistry, mineralogy and microbial community analyses collectively suggest lasting differences in redox state and element cycling between the two areas. Wolferton Fen, which experienced less historical land disturbance, had returned to a near-natural state in 2022. However, Dersingham Fen, which was historically deeply drained and experienced significant peat loss, had a low pH, thick crusts of iron (oxyhydr)oxides remaining on the surface, and very high porewater iron and sulphate concentrations. High abundances of these alternative terminal electron acceptors inhibit methanogens in Dersingham Fen, which continues to be a source of CO₂ despite anoxia.

These results suggest that iron and sulphur-rich peatlands can tolerate some degree of degradation, but extensive drainage and peat loss will likely lead to permanent contamination which remains following rewetting. However, there may be a lot to gain from restoration of such sites as rewetting can protect remaining peat and reduce CO₂ emissions whilst methane production would remain low.

How to cite: Bryce, C., Eberle, A., Ring-Hrubesh, F., Biswakarma, J., Dehaen, E., Pancost, R., and Gallego-Sala, A.: Long-term biogeochemical consequences of rewetting iron and sulphur-rich peatlands, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-16729, https://doi.org/10.5194/egusphere-egu25-16729, 2025.

Northern peatlands store ~500 Pg C and are important ecosystems for global climate regulation. Wildfire is the largest natural disturbance to peatlands within the Boreal Plains of western Canada. Historically, low-severity fires in this region release less carbon than accumulates over a fire return interval (~120 years), allowing peatlands to maintain their carbon sink function. While peat combustion (measured as the depth of burn; DOB) is typically low, ranging from 5-10 cm (representing carbon emissions of ~1 kg C m^-2), during prolonged drought, or in drained peatlands, peat burn severity can reach depths >1 m (~100 kg C m^-2), threatening the carbon sink function of boreal peatlands. We aimed to assess how peatland drainage altered the spatiotemporal variability in forest cover, aboveground biomass, and tree productivity and how these changes related to the spatial variability in peat burn severity from a fire 24 years post-drainage. Using remote sensing techniques, forest cover and biomass were estimated through time and with distance from the nearest ditch. Field surveys and a LiDAR-based analysis were conducted to measure the spatial variability in peat burn severity. Peatland drainage increased forest cover and aboveground biomass. Drained peatland margins had the greatest peat burn severity with a mean depth of burn of 26.9 ± 12.6 cm (34.0 ± 10.1 kg C m^-2) and some locations experienced DOB >90 cm (>87 kg C m^-2), where peat burn severity increased with proximity to drainage ditches and greater aboveground biomass. Peatland drainage increases both aboveground and peat fuel loads through the triggering of positive peatland drying feedbacks which increase peatland vulnerability to deep smouldering, with peatland margins experiencing the greatest peat burn severity. Drained peatlands represent a severe fire risk that can be challenging for communities and fire management agencies. Peatland restoration should be integrated into fuel management strategies to reduce the fire risk that drained peatlands pose.

How to cite: Verkaik, G., Eckert, M., Wilkinson, S., Moore, P., and Waddington, M.: Fuel loads and peat smouldering carbon loss increase following peatland drainage, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-4542, https://doi.org/10.5194/egusphere-egu25-4542, 2025.

Rates of peat extraction have rapidly declined in Finland, leaving thousands of hectares of formerly cutaway peatlands in need of management. Unlike in some other regions, in Finland there is no obligation to restore former peat extraction sites to wetlands. Afforestation is the most popular after use option of cutaway peatlands by landholders in Finland, however it is unclear how the ecosystem will respond to afforestation and whether the system can become a carbon sink quickly. In this study, we present a 3-year record of eddy covariance measurements from an afforested cutaway peatland site in Finland. We examined the carbon dioxide (CO₂)exchange dynamics of the site as it was afforested and calculated annual totals to determine whether it is a carbon source or sink.

The study site, Naarasneva, is in Southern Ostrobothnia, Finland. Peat extraction ceased in 2020 and there is an average of 1 m depth of peat remaining. The eddy covariance system was installed in August 2021. Wood ash fertilisation was applied in January 2022, followed by the planting of 2-year old Pinus sylvestris (Scots pine) saplings in June 2022. Sentinel-2 derived leaf area index (LAI) observations were used to investigate the revegetation of the site during afforestation.

The timeseries of NEE shows the exchange (uptake and emission) of CO₂ increasing over time. There was a clear effect of fertilisation, with a steady increase in the amount of CO₂ uptake in the months following fertilisation. After fertilisation, the most dominant vegetation species growing were Calamagrostis spp. (reedgrass), Epilobium spp. (willow herb) and Betula pubescens (downy birch). The increase in CO₂ uptake corresponded well with the LAI observations, which also showed a year on year increase. Annual totals of NEE show the site was a net source of 5.30 ± 0.46 t CO₂ ha^-1 yr^-1 (mean ± 95% CI) in 2022, followed by two years where it was a net sink of -1.36 ± 0.42 t CO₂ ha^-1yr^-1 in 2023 and -0.75 ± 0.56 t CO₂ ha^-1 yr^-1 in 2024.

Our results show that afforestation of a cutaway peatland can quickly turn the site into a carbon sink. While it is positive that the carbon sink functionality of former peat extraction sites may be restored quickly, the long-term climate impact of afforestation is unclear due to the continued drainage of the peat and the uncertain fate of the carbon stored in wood.

How to cite: Buzacott, A., Laasasenaho, K., Lauhanen, R., Minkkinen, K., Ojanen, P., and Lohila, A.: Afforestation turns cutaway peatland into a carbon sink, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-9706, https://doi.org/10.5194/egusphere-egu25-9706, 2025.

This study evaluates the impact of different forest management practices on soil greenhouse gas (GHG) fluxes in the Ränskälänkorpi boreal drained forested peatland, in Southern Finland. The study site is part of the HoliSoils project (Holistic management practices, modelling, and monitoring for European forest soils; https://holisoils.eu/). The study is designed for a comparative analysis of non-harvested control, traditional clear-cut harvesting, and harvesting by continuous cover forestry (57% of basal area removed), carried out in spring 2021. The aim is to quantify mean differences in soil CO₂, CH₄, and N₂O emissions and improve the annual budget estimates.

Measurements of soil CO₂, CH₄, and N₂O fluxes, soil temperature, moisture, water table depth, and air temperature were conducted post-harvest every two weeks during the growing season (May to November). Soil chemistry, understory vegetation, and microbial populations were also surveyed and evaluated for relations to observed spatial patterns of the GHG fluxes. Machine learning and Bayesian data assimilation techniques were employed (i) to identify relationships between GHG fluxes and environmental variables, and (ii) to model spatio-temporal dynamics.

Clear-cutting (CUT) resulted in an immediate and sustained rise in the water table, with mean levels significantly higher than the control (CTR) and selection harvesting (COV) sites. In all CUT, COV, and CTR sites differences in mean values of soil CO₂, CH₄, and N₂O fluxes were significant.

Our findings underscore the significance of spatio-temporal variability in GHG fluxes across different management practices, highlight the management role in variation of dynamic environmental controls on CO₂, CH₄, and N₂O fluxes, and reduce the knowledge gap on the effects of harvesting methods on GHG fluxes in boreal drained forested peatlands.

How to cite: Tupek, B., Lehtonen, A., Anttila, J., Li, Q., Martinez Garcia, E., Martinovic, T., Baldrian, P., and Mäkipää, R.: Effects of alternative harvesting managements on spatio-temporal variability of soil CO2, CH4, and N2O fluxes in boreal drained forested peatland, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-20075, https://doi.org/10.5194/egusphere-egu25-20075, 2025.

Water quality can be negatively impacted by tree felling operations and peatland restoration. This research considers how different and innovative brash (a by-product of felling trees - their tops and branches) management techniques might impact water quality following forest felling and subsequent peatland restoration.

The research design consisted of a Before-After Control-Impact experiment, wherein three different management techniques on three paired sites were compared. Two of these techniques are standard for the industry: conventional felling of trees, and the mulching of trees in-situ followed by ground smoothing. The third technique (felling multiple drifts of trees into one followed by ground smoothing) is novel and endorsed by the Scottish Government but it has not been studied previously.

Every four weeks (for 32 months) water samples and water table depths have been taken in and around treated sites. Water samples are tested for a range of water quality parameters in the laboratory. These quality indicators included: phosphate, ammonium, nitrate + nitrite, dissolved organic carbon, heavy metals, suspended solids, pH, conductivity, turbidity, etc.

Findings show that the novel technique resulted in little water quality impact (i.e., on suspended solids and nitrate + nitrite) in impacted watercourses. A spike (4.0 - 8.7 fold, mean 35.1) in ammonium occurred around one year after works were completed, and phosphate and potassium showed an elevated pulse soon after the works. Dissolved organic carbon showed strong seasonality which mirrored the control sites.

The novel technique considered here is an understudied method that is being recommended by Scottish Government agencies, and as such, science is chasing industry practice. This research aimed to sense check the impact of this technique on water quality and consider how it may impact the effectiveness of peatland restoration.

How to cite: McWilliam, A., Gaffney, P., Shah, N., and Taggart, M.: Science chasing industry: Is this novel technique as good as it seems?, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-966, https://doi.org/10.5194/egusphere-egu25-966, 2025.

Under the umbrella of international and European Union climate policies and agreements aimed at achieving climate neutrality and thus reducing greenhouse gas (GHG) emissions from drained organic soils (including the Paris agreement, the European Green Deal and the Nature Restoration Law), it is urgently necessary to estimate GHG fluxes from former peat extraction fields to provide measurement-based recommendations for further management of these areas. In addition, there is lack of quantitative estimates of contribution of peatland plant cultivation, including berries, to total GHG emissions and climate change mitigation. Here, we compared carbon dioxide (CO₂), methane (CH₄), and nitrous oxide (N₂O) fluxes from nutrient-poor organic soils (Histosols) in former peat extraction fields currently used for cranberry (Vaccinium macrocarpon) and highbush blueberry (Vaccinium corymbosum) plantations, active peat extraction fields and pristine raised bogs. GHG flux measurements were conducted over two years using a manual chamber technique at 16 study sites (at least three sites of each land-use type) across 11 different raised bogs in the hemiboreal vegetation region of Europe (in Latvia). Across the studied land-use types, mean annual net CO₂ fluxes, calculated as the difference between the annual soil heterotrophic respiration and the annual C input into soil with plant litter, ranged from near zero (-0.07 ± 0.68 t CO₂-C ha^-1 y^-1) in the pristine raised bogs to 1.56 ± 0.19 t CO₂-C ha^-1 y^-1 in active peat extraction fields. Furthermore, net CO₂ fluxes had the largest contribution to total GHG emissions in both active peat extraction fields and berry plantations. The lowest annual CH₄ fluxes were observed in cranberry plantations (6.65 ± 1.77 kg CH₄-C ha^-1 yr^-1), while the highest were in pristine raised bogs (128.0 ± 27.5 kg CH₄-C ha^-1 yr^-1), where CH₄ fluxes accounted for the largest share of total GHG emissions. Annual N₂O fluxes did not exceed 0.65 ± 0.33 kg N₂O-N ha^-1 yr^-1 (in highbush blueberry plantations) and made a relatively low contribution to total GHG emissions compared to net CO₂ and CH₄ fluxes. Across the studied land-use types, the highest total GHG fluxes (the sum of annual net CO₂, CH₄ and N₂O fluxes considering global warming potential values for a 100-year time horizon) were observed in active peat extraction fields (6.23 t CO₂ eq. ha^-1 yr^-1), while the lowest were in cranberry plantations (1.50 t CO₂ eq. ha^-1 yr^-1).

Acknowledgments: The research was conducted within the scope of the European Commission LIFE Climate Action Programme Project “Peatland restoration for greenhouse gas emission reduction and carbon sequestration in the Baltic Sea region” (LIFE21 - CCM - LV - LIFE PeatCarbon, Project number: 101074396).

How to cite: Bārdule, A., Meļņiks, R. N., Zvaigzne, Z. A., Purviņa, D., Skranda, I., Prysiazhniuk, O., Maliarenko, O., and Lazdiņš, A.: Carbon dioxide, methane and nitrous oxide fluxes from former peat extraction fields currently used for cranberry (Vaccinium macrocarpon) and highbush blueberry (Vaccinium corymbosum) plantations, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-15398, https://doi.org/10.5194/egusphere-egu25-15398, 2025.

Paludiculture is the productive use of wet or rewetted peatlands. Typha spp. is a promising paludiculture crop with usage options, including as building or insulation material. As part of the Paludi-PROGRESS project (Putting paludiculture into practice – optimization of cattail and reed cultures, project period 2022-2025) a mesocosm experiment was conducted to assess the above- and belowground biomass production and decomposition of Typha latifolia and Typha angustifolia to different water level treatments.

Using non-destructive sampling methods, we examined the annual biomass production of T. latifolia and T. angustifolia from April 2023 to April 2024 in response to either a water level gradient of -20 to +6 cm or to a drought gradient of 2 to 11 weeks. Phenospex PlantEye was used to assess the aboveground biomass production with a multi-spectral scanner. Belowground biomass production was examined with minirhizotrons and decomposition was assessed using litter bags.

At higher water levels, T. angustifolia showed higher aboveground biomass production whereas T. latifolia had higher aboveground biomass production at lower water levels. The latter also expressed higher belowground biomass production at lower water levels, whereas T. angustifolia’s belowground biomass response shifted during the vegetation period, benefitting from higher water levels until June 2023, afterwards showing higher belowground biomass production at lower water levels. Whereas both species benefit from short drought periods (2-4 weeks) with increasing belowground biomass production, longer drought periods negatively affected both species above- as well as belowground biomass production. T. angustifolia seemed to be more resilient against drought than T. latifolia. Information about the optimal water level and drought resistance of potential paludiculture crops are important information for a successful cultivation of Typha spp.

How to cite: Brendel, M., Joshi, S., and Kreyling, J.: Impact of water levels on Typha spp. in a mesocosm experiment, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-10318, https://doi.org/10.5194/egusphere-egu25-10318, 2025.

The Paludi-PROGRESS project (Paludiculture in practice: Optimisation of cattail and reed cultures, project period 2022-2025) aims to test and further develop the cultivation of cattail (Typha spp.) as a new permanent crop on wet peatlands. One of the main tasks is to evaluate the productivity and biomass quality of cattail on a 10 ha rewetted peatland, established in September 2019.

In the time period of 2021 until 2024 biomass samples were collected twice a year, in summer (July) and winter (November/December). Prior to the first sampling in 2021, four different density categories were identified based on the visual impression of the cattail vegetation (dense to rare cattail plant occurrence). Sampling plots were randomly distributed within these sub-areas of the pilot site (10 per density category). Since a partial harvest took place on a small area in December 2021 and 2023, the influence of cutting on the biomass could also be observed in the following years. Furthermore, the site was fully harvested at the beginning of 2023. To monitor the cattail vegetation, several parameters were recorded for each plot: e.g. number of cattail plants and spadices, plant height and diameter, dry weight, water content and chemical composition (carbon, nitrogen, phosphorous, potassium, lignin, cellulose and hemicellulose).

From winter 2021 to winter 2024, cattail biomass productivity has more than tripled from 1.8 to 6.8 t dm/ha when considering the total pilot site. In the areas with dense cattail vegetation, the biomass increased from 4.1 to 8.2 t dm/ha. Different stand densities showed an influence on morphological parameters, but had a minor effect on the chemical composition of the biomass. The harvest trial in 2021 did not have a significant impact on the parameters considered. In winter 2023, the biomass productivity declined to 3.6 (total site) and 4.9 t dm/ha (dense areas). Next to other environmental factors, harvesting the total site could have shown a negative effect on the regrowth of cattail in 2023.

The collected data show unique results about the development of cattails on a large-scale pilot site and therefore provide important information for future use of cattail from commercial-scale cultivation. Additionally, it is important to evaluate whether the given growing conditions lead to appropriate biomass quality for various utilization options.

How to cite: Köhn, N., Brendel, M., Neubert, J., Wichmann, S., and Kreyling, J.: Productivity and biomass quality of cattail (Typha spp.) on a 10 ha paludiculture pilot site in northeast Germany, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-10490, https://doi.org/10.5194/egusphere-egu25-10490, 2025.

Drained agricultural peatlands are a large source of greenhouse gasses (GHGs) due to peat oxidation. Paludiculture, where flood-tolerant grasses are grown on rewetted peatlands, might be a potential strategy for climate change mitigation by reducing GHG emissions while maintaining biomass production. This study assessed the impact of different harvest and fertilization treatments of reed canary grass (Phalaris arundinacea, cv. Lipaula; RCG) on GHG exchange dynamics and global warming potential (GWP) in two measurement periods (5 May 2020 to 4 May 2021, and 18 May 2021 to 17 May 2022) at a fen with shallow water tables depths (annual mean WTD of -10 cm and -8 cm, respectively) and ca. 2 m deep peat. RCG was established in 2018 and in the following years management strategies with 2 or 5 cuts per year were compared with a non-harvested scenario (0-cut). Treatments involving 2 and 5 annual cuts were fertilized with 200 kg N ha^-1 yr^-1 in equal split doses for each cut while the 0-cut scenario remained unfertilized. Fluxes of CO₂, CH₄, and N₂O (only 2020-21) were measured with fortnightly intervals using the manual chamber technique and cumulative fluxes were derived by empirical models.

Yields of RCG decreased slightly over the years with 15.6, 11.5 and 8.9 t DM ha^-1 yr^-1 for the 2-cut system and 14.5, 9.4 and 8.6 for the 5-cut system in 2019, 2020 and 2021, respectively. Mean annual WTD of -13 cm in 2019 was slightly lower than the following years. In general, photosynthetic CO₂ uptake was higher in treatments with active biomass management, but carbon export in the harvested biomass offset this benefit, resulting in a near-equal net ecosystem carbon balance (NECB) across all treatments ranging from 36.0 to 43.6 and 17.1 to 28.2 t CO₂ ha^-1 yr^-1 in 2020-21 and 2021-22, respectively. The mean NECB of 22.5 t CO₂ ha^-1 yr^-1 in 2021-22 across treatments was significantly lower than the mean of 38.7 t CO₂ ha^-1 yr^-1 in 2020-21. This might be partly explained by the slightly increasing WTD due to lack of ditch maintenance and more precipitation, but the flux effect of increasing WTD on decreased peat oxidation may also be delayed by a few years. Emissions of CH₄ remained low during 2020-21 (1.1–1.9 t CO₂e ha^-1 yr^-1), while N₂O emissions were relatively high (4.0-5.7 t CO₂e ha^-1 yr^-1) without any treatment effects. In 2021-22, CH₄ emissions increased to 2.6-3.7 t CO₂e ha^-1 yr^-1 equivalent to 11.3 % of the total carbon emission in CO₂ equivalents. Although the peat field seemed uniform, large variation within treatments was seen across the experimental blocks which could be linked to differences in soil nutrient concentrations and water chemistry. Overall, it can be concluded that paludiculture and the non-managed restoration scenario exhibited comparable climate outcomes thereby offering flexibility in land-use options for peatland restoration. However, results also suggested that biomass harvest can reduce GHG emissions in the more productive area, while leaving the biomass unmanaged was advantageous in the less productive area of the field.

How to cite: Lærke, P. E., Pullens, J. W. M., Christiansen, J. R., Larsen, K. S., and Rodriguez, A. F.: Two years of GHG emissions from reed canary grass under different harvest management intensities in a rewetting fen peatland, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-11328, https://doi.org/10.5194/egusphere-egu25-11328, 2025.

To meet climate targets, drained peatlands will need to be rewetted, thereby reducing greenhouse gas emissions from agricultural landscapes. However, possibilities for continued productive use of these landscapes are also necessary. A novel concept that has emerged in recent years is peatland photovoltaics (PV) in combination with peatland rewetting. Until now, there is almost no practical experience with peatland PV on rewetted peat soils; our project explores the biodiversity of a ‘wet’ peatland PV site.

For a comprehensive understanding of the biological implications of rewetting and solar power generation, a multi-taxon study is being conducted on vegetation, spiders, carabid beetles, birds, amphibians and bats. Paired with traditional field survey techniques, methods from the rapidly evolving field of bioacoustics including passive acoustic monitoring and machine learning are being used to gather data from the entire growing season. This presentation will provide initial results on plant and bird biodiversity at a 30-hectare rewetted peatland PV site in Northern Germany. A space-for-time approach was used to assess biodiversity in a drained, intensively used peatland site compared to the rewetted solar park. Initial results indicate that while species diversity is not significantly different, the plant community is. The plant community within the rewetted solar park has more species adapted to wet conditions, while the species within the drained peatland site are largely typical agricultural species.

Given the need to rewet peatlands and the rapid growth of the solar power industry, it is necessary to understand the biological implications of such a land use, as well as any possibilities for synergies between climate protection and renewable energy production. 

How to cite: Martens, H. R., Kreying, J., and Tanneberger, F.: Biodiversity Potential in Solar Parks on Rewetted Peatlands, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-10373, https://doi.org/10.5194/egusphere-egu25-10373, 2025.

Measurable restoration targets, and indicators of success for restoration are critically required for restoration programmes to successfully measure and appraisal of interventions. 

Traditionally this has been done by a combination of hydrology monitoring, vegetation surveys and GHG emissions monitoring. These methods can be both costly in terms of time and money and are not always included as part of traditional UK-based conservation and restoration funding criteria written by the funding providers, such as landfill tax and government funding.

They also require trained practitioners or partnership working (e.g. with academia or specialist consultancies) to do effectively, especially at the scale needed to meet the target of 282 thousand Ha of peat being actively under restoration by 2050, as set by the British government as part of the Peat Action Plan (PAP) in 2021. 

One of the major challenges of assessing restoration efficacy is the lengthy period needed to reach any restoration targets and the therefore associated long-term monitoring needed to measure this. The processes at work can take decades to reach completion, resulting in costly and far-sighted monitoring programmes.  

This research aims to develop a tracer for peatland status based on elucidating the extent to which old C stored within degraded and rehabilitated peatland sites is being emitted. It will do this by delineating the relationships between the age of respired soil carbon (C) being lost from peatlands and current, historical, and restorative land management of sites. 

This research applied highly novel application of ¹⁴CO₂ and dissolved ¹⁴CO₂ (D¹⁴CO₂) Carbon dating of the soil and fluvial emissions across the time chrono-sequence of a lowland-raised bog restoration programme and combine with data on CO₂ soil emissions (NER) and primary productivity data (GPP) to aid in the characterisation of emissions for each site. This approach aims to provide an insight into the stability of the peat horizon, the role of modern and older carbon mobility plays across restoration strategies and the estimated depth at which emissions originate. Emissions were captured using molecular sieves connected from closed chambers, with flux passively sampled over a 1-month period. This was combined with fluvial D¹⁴CO₂ samplers deployed in parallel in adjacent ditches to compare the difference in ages between soil respiration and fluvial emissions.

 This simple tracer could revolutionise peatland conservation science through providing an accessible, quantitative approach to assessing the extent to which C lost is either dominated by modern C gained from recent plant grown or C respiration of older, deeper organic matter stores (representing a net loss of stored C to the atmosphere). As reinstatement of stable, long-term C storage is one of the key aims of conservation bodies, government, and landowners, assessing this directly would seem an obvious and important measure especially with funding shortfalls identified leading to a more blended funding approach to peatland restoration. 

How to cite: Longden, M., Nolan, M., Garnett, M., Page, S., and Evers, S.: 14C dating of peat surface - emitted dissolved fluvial CO2 carbon to support management and decision-making for UK Lowland peatlands, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-20993, https://doi.org/10.5194/egusphere-egu25-20993, 2025.

Human industry has contaminated peatlands through the atmospheric deposition of pollutants released by industrial processes over many centuries. Relative to other ecosystems, peatlands sequester a far greater proportion of toxic metals than their areal extent. This is especially true in industry-impacted landscapes, where toxic metals in surficial peat can be elevated well above natural concentrations. Despite peatlands acting as contaminant sinks that can maintain their carbon storage functionality under low metal concentrations, high rates of metal pollution can lead to the degradation of peatland processes that sustain carbon sequestration. For example, the loss of keystone peatland species, such as Sphagnum mosses, limits peat accumulation and long-term carbon accumulation. Therefore, in these degraded peatlands, peat forming processes are often suppressed even decades after the source of contamination has reduced or ceased.

Once degraded, peatlands become susceptible to additional disturbances such as fire or erosion, which can release their toxic legacy into the environment and drinking water. Predicted future warmer and drier conditions are expected to increase wildfire prevalence on the landscape and may be further compounded by land use change.  The release of previously sequestered metals arguably represents one of the largest contemporary global environmental disasters and greatest future global environmental challenge.

In this paper, we present an in-depth review of existing literature on ombrotrophic peatland metal contamination from a range of disciplines. After a detailed search and screening process, data were extracted from 97 studies. 500 individual points covering 26 countries were extracted from these studies, which were published between 1973 to 2022. For each study, the depth at which maximum heavy metal concentration (C_max) occurred was recorded, along with surface concentration and concentration at depth. Using Kernel Density Estimates, the distribution of C_max was typically within the top 0.2m of the peat surface across all studies, though with variation in the mean depth profiles between different metals. For example, C_max for Cd and Zn typically peaked at 0.1m below the surface with few studies showing C_max below 0.2m. As, Cu and Pb also had mean C_max values <0.2m depth but showed a tail of C_max values extending to at least 0.5m depth.

The review provides much needed understanding of the spatial extent of peatland contamination as an essential first step in tackling contaminant release from peatland fires. By quantifying the extent of heavy metals at depth in the peat profile, this work can link with peat fire modellers, ecohydrologists and climate scientists to better predict the impact of severe fires under future climate and land use change.

How to cite: Shuttleworth, E., Johnston, A., Clay, G., Mair, T., Waddington, M., McCarter, C., Basiliko, N., Gunn, J., Beckett, P., Byrne, K., Swindles, G., and Fewster, R.: Understanding the potential for disturbance-induced contaminant release from degraded peatlands: a global review of heavy metals in peatlands, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-13582, https://doi.org/10.5194/egusphere-egu25-13582, 2025.

Peatland ecosystems, while covering only ~3% of the land surface area, are globally-important sinks of atmospheric carbon dioxide and regionally-important sinks of pollutants such as toxic metals and metalloids. While metal concentrations in peatlands are generally low, concentrations can be far higher near current and historic industrial centres, particularly in the upper few decimetres of the peat profile. Under normal conditions these metals remain safely sequestered in the peat. However, there is concern that, in addition to direct carbon emissions, peatland wildfires could represent a major pathway for metal mobilization and transport. Moreover, peat fires are dominated by smouldering, which is a low temperature combustion that leads to high concentrations of particulate matter within the smoke, representing a major health risk for communities impacted by wildfire smoke plumes.

With projected future climate change, annual area burned and subsequent carbon emissions are expected to rise, with drastic increases associated with high climate-forcing scenarios. In addition to greater area burned, higher evaporative losses associated with warming conditions may lead to increased peat smouldering vulnerability during wildfire. However, differences in local climate, projected changes in precipitation, and peatland type may have strong regionally-dependent mitigating effects.

Using the MODIS burned area product, we first develop an empirical relationship between current average area burned and regional climate. Using the climate-driven relationship, we estimate future changes in area burned from multiple climate models (CMIP6 GCMs) and across several climate-forcing scenarios (SSP 2-4.5, 3-7.0,and 5-8.5). In addition to changes in area burned, peat smouldering carbon loss is evaluated by simulating peat moisture profiles using HYDRUS-1D within a phase-space defined by evaporative demand and water table (WT) position. Under contemporary conditions, peat smouldering loss is concordant with the depth of peat that exceeds a critical soil water tension threshold under steady state conditions using the mean WT position. The impacts of climate change on smouldering carbon loss is then estimated based on the change in position within the evaporative demand–WT phase space. Peatland WT sensitivity to temperature and precipitation are taken from the literature and used to estimate changes in WT based on GCM projections across SSPs. Combined with published data on peatland type and location, we produce some of the first ever hemisphere-wide estimates of northern peatland carbon loss from smouldering due to climate change. 

These spatially explicit results are used to highlight regions of overlap between increased burn area and severity with areas of high peat metal contamination. Taken together with estimates of particulate emissions from smouldering combustion, we provide an estimate of how climate change may increase global particulate matter emissions from northern peatlands. Moreover, uncertainty in the empirical relation and inter-model variability are used to quantify the confidence intervals for both projected area burned, peat burn severity, and thus particulate matter emissions, in order to highlight where future efforts are best focused for improving robustness of future projections.

How to cite: Moore, P., McCarter, C. P. R., Sutton, O., and Waddington, J.: Northern peatlands under fire: Projecting smouldering combustion loss in an uncertain future with implications for atmospheric metal emissions, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-11827, https://doi.org/10.5194/egusphere-egu25-11827, 2025.

This study examined the impact of different water management (WM) strategies and farming practices on greenhouse gas (GHG) emissions from organic soils at two sites in Southern Germany—the Altbayerisches Donaumoos and the Freisinger Moos. The aim was to assess whether specific WM and land-use measures could stabilize water tables and reduce CO₂, CH₄, and N₂O emissions, while maintaining agricultural productivity.

In our test site in the Altbayerisches Donaumoos (arable land growing grain maize under conventional and organic management), four field treatments were established: two with controlled WM via subsurface irrigation and two reference sites without active WM. Results from 2022 showed reduced total GHG emissions—mainly driven by lower CO₂ and N₂O fluxes—on the WM plots compared to references, especially under organic management. CH₄ fluxes were negligible, indicating a minor effect on the overall budget.

In the test site Freisinger Moos (grassland with three cuts per year), four treatments (two with subsurface irrigation at 30 and 50 cm depth, one with a simple raised water table through a weir, and one “pipe-less” subsurface system) were monitored during 2022 and 2023. Despite generally higher water tables in the irrigated plots, both CO₂ and N₂O emissions remained substantial. The 50 cm subsurface irrigation consistently showed the highest GHG fluxes, partly due to more intensive management and greater biomass exports. Notably, all treatments displayed increased emissions in 2023 compared to 2022—a rise attributed to possible changes in water availability, climatic factors, and residual effects of organic fertilization.

These findings highlight the complexity of balancing water management, agriculture, and climate protection in peatland regions. While raising the water table can reduce peat decomposition, achieving significant mitigation requires careful consideration of fertilizer inputs, crop type, and long-term soil conditions. While water management did have an effect on reducing CO₂ emissions, this is not yet sufficient to be seen as a climate friendly practice. Future research should address long-term impacts and refine water-level targets to further optimize land use on organic soils and mitigate associated greenhouse gas emissions.

How to cite: Lenz, D., Schlaipfer, M., Meyer, H., Gutermuth, S., Jörg, L., Ludwig, R., and Drösler, M.: Influence of water management on GHG-balances along a land use intensity gradient in fen peatlands , EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-11079, https://doi.org/10.5194/egusphere-egu25-11079, 2025.

Drained peatlands under intensive agricultural land use are hotspots of greenhouse gas (GHG) emissions. While management intensity and soil water status have been identified as major controlling factors, only few studies focussed on temporal dynamics and the contribution of nitrous oxide (N₂O) and methane (CH₄) to full annual GHG balances, mainly due to the lack of continuous observations in high temporal resolution. We present four years of parallel eddy-covariance (EC) and chamber GHG measurements at an intensively managed grassland site on bog peat soil. The site (DE-Okd) is part of the Integrated Carbon Observation System (ICOS) and represents common agricultural practice in Northwest Germany.

Average N₂O fluxes measured by EC were consistently higher than those obtained by chambers. Following a grassland renewal, vegetation development in chamber frames was found to be more favourable than the average growth on the entire field that is seen by the EC tower. Poor grass development was identified by vegetation indices from remote sensing data and probably led to nitrogen surplus in the soil as observed by high ammonium and nitrate concentrations in drainage ditches. These conditions likely favoured both high N₂O emissions and simultaneously high rates of nitrogen leaching. While N₂O emissions made up considerable fractions of full annual GHG balances (~5 to 31%), the contribution of CH₄ was negligible with hardly any significant fluxes detected by chambers and both seasonally varying emissions and uptake measured by EC cancelling out to non-significant shares to the overall budget.

N₂O and CH₄ emissions were strongly influenced by biometeorological factors and land management. Highest N₂O peaks were observed two days after fertilizer application coinciding with about one week after grass cutting and highlighting a well-chosen chamber sampling scheme after management events. Further, N₂O emissions were elevated during daytime under medium soil moisture and high soil temperature regimes, while CH₄ emissions were strongly correlated with soil moisture dropping to nearly zero exchange under dry conditions.

Based on chamber measurements, the overall GHG balance of the site including harvest and carbon input through organic fertilization was in the range of 20 to 25 t CO₂-equivalents ha^-1 yr^-1 in the period from 2020 to 2023 with generally higher emissions in dryer years. Replacing chamber N₂O and CH₄ by EC data for the full budget, individual annual values increased between 0.8 and 10.1 t CO₂-equivalents ha^-1 yr^-1.

We conclude that the combination of EC and chamber measurements helped identifying temporal dynamics of GHG exchange for a better understanding of ecosystem functioning and quantifying method-based uncertainties. Conventionally managed grassland on drained peat soils with high fertilizer input and 4 to 5 grass cuts per year proved to be a significant net GHG emission source. Accounting for footprint heterogeneity – for example through adequate positioning of chamber frames – is of utmost importance for robust determination of total GHG balances at site-level scale.

How to cite: Lang, T. T. M., Tiemeyer, B., Wintjen, P., Düvel, D., Rüffer, J. J., Offermanns, L., Dettmann, U., and Brümmer, C.: Seasonal conditions and flux footprints control the contribution of N2O and CH4 to the full GHG balance at grassland on peat soil, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-10958, https://doi.org/10.5194/egusphere-egu25-10958, 2025.

Up to 40% of U.K. grown vegetables are produced on lowland peat. This land use type is the highest emitter of carbon per unit area in the U.K., with drained agriculture on peatlands representing 3% of reported national greenhouse gas (GHG) emissions. This land use type impacts many other ecosystems service including the loss of topsoil and compaction, increased flood risk and biodiversity. However, total agricultural production from lowland peat equates to £1.23 billion in U.K. revenue providing income to farmers and jobs in the local area. Paludiculture and wetter farming are increasingly being considered as more sustainable alternatives to conventional farming to enable the continued productive use of peatlands whilst mitigating the impacts of peatland cultivation. Whilst there are several trials considering various paludiculture crops, there is a gap in the research which focuses on food crops in the U.K. We present the preliminary findings of a three-year wetter farming experiment focused on food crops in which carbon dioxide (CO₂) and methane (CH₄) emissions were measured from three agricultural lowland peat bog (ALPB) sites in the Northwest of England. The wetter farming experimental site in Greater Manchester was rewetted in March 2022. Celery (2022, 2023 and 2024) and lettuce (2024) crops were grown at a higher water table with annual averages of between 30.5 cm and 38.8 cm below the soil surface. The other two sites represented business as usual (BaU) drainage agriculture on ALPB with annual average water table depths between 69.1 cm and 96.2 cm below the soil surface. Both BaU sites are situated in Lancashire; one is a vegetable farm at which celery (2022, 2023 and 2024) and lettuce (2024) crops were monitored, the other farm is cereal farm where wheat fields were monitored (2022 and 2023). CO₂ and CH₄ emissions factors for the cultivation of these crops at various water table depths will be presented. In addition, we will discuss the impacts of specific farming activities (ploughing/cultivation, planting, fertilizer application and harvest) on CO₂ and CH₄ emission at all three sites. These emissions will be linked to both soil chemistry and physical attributes.

How to cite: Nolan, M., Longden, M., Hoskins, R., Andrews, L., Adams, A., Checkland, S., and Evers, S.: Food on Peat: The impact of wetter farming practices on greenhouse gas emissions from food crops on agricultural lowland peat bogs in the Northwest of England., EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-18465, https://doi.org/10.5194/egusphere-egu25-18465, 2025.

The UK’s lowland peatlands occupy ~465,000 ha and are distributed across much of the country. The large majority (90%) of this lowland peat has been drained for agriculture, creating productive, fertile soils, but also exposing previously waterlogged organic matter to decomposition. Peatland drainage can alter aquatic biogeochemistry by increasing dissolved organic carbon fluxes to surface waters and promoting greenhouse gas (GHG) emissions from drainage ditches. Peatland rewetting has been demonstrated as an efficient mitigation technique for peatland GHG emissions. It is critical to understand how peatland drainage and subsequent rewetting may influence GHG emissions, as drainage may have allowed long-term accumulation of substances of agricultural or industrial origins, such as macronutrients (e.g. carbon, nitrogen, phosphorous) and heavy metals, which are released upon rewetting. Here, we present the results of an on-going, national-scale field study (part of the LowlandPeat3 project, https://lowlandpeat.ceh.ac.uk/lowlandpeat3) examining the spatio-temporal dynamics of GHG emissions in ditches draining arable lands (including conventional and regenerative agriculture) at paired “business as usual” and rewetted sites, during the baseline period prior to rewetting. We have measured carbon dioxide, methane, and nitrous oxide concentrations (and modelled fluxes) approximately monthly from sites across England. The results of this research will help us understand the risks and benefits of peatland rewetting on water quality, drinking water, aquatic ecology, and climate, to help inform lowland peat management and policy.  

How to cite: Silverthorn, T., Andrews, L., Baker, F., Baugh, L., Bell, C., Chiverrell, R., Cumming, A., Evans, C. D., Evers, S., Flint, L., Holman, I., Jovani, J., McKenzie, R., Monsen-Elvik, E., Southon, F., Thenga, H., and Peacock, M.: Land management effects on ditch greenhouse gas dynamics in UK lowland peatlands , EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-8601, https://doi.org/10.5194/egusphere-egu25-8601, 2025.

Large areas of peatlands have been drained for agricultural and forestry purposes due to human activities. This drainage disrupts the natural hydrology of peatlands, leading to increased peat decomposition and turning these ecosystems into significant sources of greenhouse gas (GHG) emissions. Since the 1930s, extensive peatland areas in northern Norway have been drained and converted to agricultural land. To mitigate GHG emissions while maintaining biomass production, various management practices, including rewetting, are being promoted for these peatlands. Nevertheless, the impact of these mitigation measures on the peatland GHG balance remains largely unexplored.

We investigated grass productivity and the GHG balance in response to peatland cultivation under varying fertilization and hydrological treatments at a site in northern Norway. GHG fluxes (CO₂, CH₄, and N₂O) were measured using 30 automatic chambers at sub-daily intervals during the growing seasons of 2022-2024.

High water levels inhibited CO₂ emissions by suppressing ecosystem respiration, converting the ecosystem from a substantial CO₂ source to a sink or neutral state. Conversely, high water levels enhanced CH₄ emissions, while low water level plots remained CH₄ neutral. Sporadic N₂O emissions were observed to be higher under the more intensive fertilization regimen. Our results further highlight the critical role of harvest in determining the overall GHG and carbon balance in the ecosystem. This study has significant implications for guiding sustainable peatland management in Arctic regions.

How to cite: Zhao, J., Mastepanov, M., Klutsch, C., Silvennoinen, H., Kniha, D., Wara, S., and Kjær, R.: Can peatlands be used sustainably for agriculture in the Arctic Norway?, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-9025, https://doi.org/10.5194/egusphere-egu25-9025, 2025.

Peatlands store around 30% of the world's soil organic carbon and therefore play a significant part in mitigating greenhouse gas (GHG) emissions. Some peatlands have been converted to agricultural use through artificial drainage and farming practices,leading to the accelerated release of carbon from the land to the atmosphere. However, the combination of soil characteristics, hydraulic properties and field management operations all play an important role in determining how much GHGs are emitted from the agricultural sites. The aim of this study is to 1) evaluate the applicability of the LandscapeDNDC model to cultivated peatlands by comparing the simulation outputs with the corresponding observations in the study site, and 2) assess the effects of the water table changes on GHG emissions. The LandscapeDNDC is a process-based model that can handle carbon and nitrogen cycling. The model can incorporate various input data, such as management, meteorological and water table data, and therefore provides a well-rounded framework for studying the effect of manipulating these input data on GHG emissions.

We performed the study at Luke Ruukki Research Station on the NorPeat platform, divided into 6 separate drainage blocks with varying peat depths (20 - 80 cm). Continuous flux measurements (June 2019 onwards) were collected at the site as well as block-specific dark chamber measurements of CO2 and N2O emissions. Each of the blocks had groundwater pipes equipped with pressure sensors to continuously measure the water table level. In addition, intensive measurements of soil properties and yield were carried out on the site during the study years 2019 - 2022, allowing us to establish a realistic site profile for our simulation runs.

The simulations were first validated with two meters: the satellite measurements of leaf area index and measurements of soil moisture. The model reproduced the observed variability in all blocks for both meters (R2 > 0.5) and was sufficiently able to simulate the observed CO2 and N2O fluxes. After analysing and ensuring that the model was able to reproduce the biochemical and hydraulic dynamics observed in the study site, we studied the three different water table scenarios and their effects on the GHG fluxes. In the scenarios the water table was raised on average to 15, 30, and 50 cm below the soil surface. These water table changes altered the soil respiration and nitrogen cycling, and provided insight into how peat thickness affects emissions. In addition, the study helped to quantify the mitigation effect of the raised water table, relieving the potential that water management could have on controlling GHG emissions.

How to cite: Kajasilta, H., Niiranen, M., Läpikivi, M., Liimatainen, M., Gerin, S., Kraus, D., Kulmala, L., Liski, J., and Vira, J.: The effect of water table depth on GHG emissions in an agricultural peatland with varying peat depth, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-12529, https://doi.org/10.5194/egusphere-egu25-12529, 2025.