Agricultural Peat Soils
Discover the story of Ireland's agricultural peat soils and how FarmPEAT's project farmers manage them for nature.
This story map can be used as a resource for agricultural and environmental science students at the Leaving Certificate or Higher Education Level. You can find resources for younger age groups on the Irish Peatland Conservation Council website.
What are peat soils?
Peat soils contain partially decomposed organic matter formed under wet, anaerobic (i.e. little or no oxygen) conditions. Peatlands cover approximately 1.46 million ha or 21% of Ireland's land surface. Peatland habitats include fens, blanket bogs, and raised bogs. These form in different ways and have their unique characteristics.
Fens are groundwater-fed, alkaline, and nutrient-rich, while bogs are rainwater-fed, acidic, and nutrient-poor. Blanket bogs formed on poorly-drained soil in mountains with heavy rain. Raised bogs formed in lakes in the Midlands of Ireland.
Peatland habitats store carbon, control the flow of water through the landscape, and support unique plants and wildlife. View fun facts about bogland biodiversity here .
The most important plant on bogs is Sphagnum moss. It has no root system, so absorbs nutrients from the surrounding water. Due to its sponge-like hyaline cells, it stores up to 20 times its weight in water and builds the bog as it grows and dies off. When there's a low water table, the hyaline cells fill with air and become bleached. This reflects sunlight and prevents further water loss.
Unfortunately, bogs were not valued for their benefits to climate and biodiversity. They were viewed as either a source of fuel or wastelands and often drained. This negatively affects the peat soils because when they dry out, they become oxygenated.
Oxygen speeds up the decomposition of organic matter in the soil, so it becomes a carbon source rather than a carbon sink.
Peatland biodiversity is also affected because the plants that need wet and acidic conditions to grow, such as Sphagnum moss, can no longer thrive there.
"A healthy bog is a wet bog."
Introducing Agricultural Peat Soils
Peatlands were drained for turf, forestry, horticulture, and agriculture. The FarmPEAT Project focuses on the latter. Our project farmers manage the land around raised bogs in the Midlands. Many of these bogs were drained for turf extraction and their margins converted for farming. These marginal areas are now referred to as agricultural peat soils.
Carbon Emissions
The 330,000-339,000 ha of mapped agricultural peat soils in Ireland are releasing an estimated 3.9 million t/CO2eq/year, according to the 2024 National Inventory Report .
These soils contribute to grassland being the second largest emissions source in the Land Use, Land-Use Change and Forestry category, hence the need to reduce their management intensity and raise the water table.
Peat Wastage
Another issue arising from drained peat soils is peat wastage.
Peat wastage and subsidence occur through drying and shrinkage, consolidation by loss of buoyant force, contraction by capillary force, and biochemical oxidation. In essence, the bulk of the peat soil is lost as gases which are emitted to the atmosphere, primarily as CO 2 , or water, as dissolved organic carbon (DOC) (Daly, 2023) .
In a grassland on peat, the soil on which the agricultural activity relies is wasting away, or as Donal Daly puts it, “it is a wasting asset”. The rate of peat wastage has been estimated at 1-2 cm/year but varies depending on the water table depth, peat thickness and type, climate, land use, and fertiliser (Daly, 2023). Drainage intensity is the main driver, but the rate of oxidation further increases due to tillage, warmer temperatures, high pH (e.g. from liming), or fertiliser applications (Daly, 2023).
In the coming years, the peaty soil will continue to waste way, and the land surface will continue to subside until the water table is within perhaps 10-20 cm of the surface, significantly lowering the productivity of the land for the farmer.
Example 1: The background image by Phil Brewin shows peat wastage at the Somerset Levels; the pylon footings were level with the ground in 1960 but have now dropped to where the arrows end.
Example 2:
Timeline of Farm Drainage
The reduced management intensity and rewetting of agricultural peat soils is contrary to what the government of Ireland has asked farmers to do in previous years. For the past 60 years or so, Ireland has encouraged farmers to make their land more productive and has provided grants to drain ‘marginal’ wet ground, including peaty soils. Farm families still have memories of helping their grandparents and parents to drain the land and convert it to profitable, productive grazing ground, something they were, in most instances, extremely proud to achieve (FarmPEAT farmers, personal communication).
The Department of Agriculture now intends to ask these farmers to reverse this back-breaking work. It is not expected that farmers will readily take this up unless they believe there is sound science and government commitment behind them. The results-based approach is a way of incentivising a change in management practices on farms. Therefore, the FarmPEAT Project was set up to pilot a results-based scheme on agricultural peat soils in the Midlands.
The timeline below is derived from Tuohy et al. (2023) and outlines the recent story of farm drainage of peat soils in Ireland:
1842
The Office of Public Works commenced various arterial and field drainage schemes.
1949-1980s
The Land Rehabilitation Project provided state aid for farm drainage.
1984
The new EU Milk Quota reduced incentives to maximise farm productivity, causing a pause in drainage works.
2015
The removal of the EU Milk Quota drove a renewed interest in cleaning and restoring farm drains that had been previously installed but not maintained.
2021
The Climate Action and Low Carbon Development (Amendment) Act 2021 is introduced and Sectoral Emissions Ceilings are developed to ensure every sector plays its part in achieving a 51% reduction in greenhouse gas emissions by 2030. The Climate Change Advisory Council's Carbon Budgets Technical report illustrates that of the 337,000 ha of drained organic soils, 110,000 ha (~33%) should be rewetted by 2030 if Ireland is to reach its national targets. The Department of Agriculture, Food and the Marine launches the FarmPEAT and Farm Carbon Projects under the European Innovation Partnership (EIP) Scheme. These projects will pilot new ways of managing agricultural peat soils to reduce carbon emissions and protect nature.
2022
The Teagasc Manual on Drainage and Soil Management emphasised that "further drainage of high organic content or peat cannot be justified and a significant programme of water table management should be considered on those organic soils that were previously drained."
2024
The European Union adopted the Nature Restoration Law on 17 June 2024. It includes targets for raising the water table on drained peat soils and provides further political momentum to establish long-term funding for farmers who join voluntary schemes.
What's next?
The Midlands Carbon Catchment Study is expected to launch in 2025 to build on the work of the FarmPEAT and Farm Carbon EIPs. Under the EU Nature Restoration Law, Ireland has also committed to putting a National Restoration Plan in place by 2026.
Solution: Raising Water Table
In FarmPEAT, rewetting means managing the water table and reducing artificial drainage, it does not necessarily mean flooding the land or restoring it to peatland vegetation.
Figure 1. Raising the water table to within 30cm of the surface reduces carbon emissions but allows farming to continue.
The water table is the boundary between the unsaturated soil and saturated soil. The higher the water table, the more saturated the soil is with water. When soil is saturated, the lack of oxygen slows the decomposition of organic matter and the release of carbon. Therefore, the height of the water table is the single most important factor determining the greenhouse gas emissions from peat soils.
The good news is that we can partially raise the water table without flooding the land on the surface, enabling farming to continue. Evans et al. (2021) found that every 10cm increase in the water table reduces emissions by 3 tCO2e/ha/year. In other words, every little helps! In FarmPEAT, we aim for the water table to be at least within 30cm of the bank level.
What are the factors affecting the success of raising the water table?
These factors were explained in Dr Florence Renou-Wilson's webinar with Birdwatch Ireland in 2023:
- How long has it been drained or how long has it been rewetted?
- What is the vegetation on top?
- What is the current and past land management?
- What is the nutrient status?
- What is the residual peat depth?
- What is under the peat?
- What is the climate/geography/topography?
- Do you want to do active rewetting – can you easily yourself manage how much water is moving into the field or not? Is it independent on you? Are you mostly dependent on surface water or is the hydrology mostly subsurface?
- How intensively are you managing the site? How many cows, sheep, grass are you taking out of your site? Are you planning on going the whole way towards paludiculture use?
How to Raise the Water Table
01 / 07
Scroll to see the before-and-after of a peat dam installed at a project farm in Co. Roscommon. The black L-shaped pipe is placed at a height agreed on together with the landowner. Water flows in one end and out the other, which controls the level of water in the drain.
Scroll to see the before-and-after of a plastic dam installed at a project farm near Clonboley Bog, Co. Roscommon. The central notch is cut at a level agreed on together with the landowner. It allows water to continue flowing once it reaches the desired level.
Paying for Results
We developed six scorecards with habitat-specific criteria divided into ecological integrity, hydrological integrity, and damaging activities. Categories are weighted according to their relative importance. A higher score, indicating better habitat quality for nature, produces a higher results-based payment for the farmer.
- Low Quality (Score 0-3) = €0-75/ha
- Moderate Quality (Score 4-6) = €150-250/ha
- High Quality (Score 7-10) = €300-450 /ha
We had a scorecard for peatland, wet grassland, dry grassland, woodland, field boundaries, and the Whole-Farm Assessment.
Higher Nature Quality = Higher Payment
This is multiplied by the whole-farm assessment captures the farm’s overall risks to water quality and greenhouse gas emissions. E.g. livestock accessing drains and watercourses. It affects the final score as a multiplier:
- Very Poor Score = Payment reduced by 40%
- Poor Score = Payment reduced by 20%
- Good Score = Maximum Results-Based Payment
- Excellent Score = Payment multiplied by 20%
How can farmers increase their score?
Supporting actions are voluntary measures designed to enhance the environmental quality of participating farms. These actions aim to improve habitat quality, reduce risks to water quality, and enhance the hydrological condition of peat soils.
FarmPEAT funds 25-100% of the supporting actions. For example, some farm access improvements (e.g. footbridges) are 25-50% funded, water protection measures (e.g. fencing) are 50% funded, invasive species control (e.g. Rhododendron clearance) is 75% funded, and peat restoration measures (e.g. dam installation) are 100% funded.
- An annual works plan is made collaboratively between the project team and the farmer. It proposes potential supporting actions including their location, scope, and estimated costs.
- The farmer, with support from the project team, pays for and completes the work.
- The farmer submits a payment claim, including a declaration of completion and supporting documents, e.g. receipts or photos.
- The project team verifies the actions are completed to the standard set out in the specifications, this may involve a site visit.
- The project team submit a claim to the Department and then reimburse the farmer.
These supporting actions payments are additional to the results-based payment. They can help the farmer to improve their habitat quality and reduce environmental risks, therefore increasing their results-based payment for future years.
