Lowland agricultural peat: why is it important?

88% of all the greenhouse gas emissions from peat in the UK comes from lowland peat.

Whilst we often hear about the importance of protecting upland peat, lowland peat – particularly lowland agricultural peat – has received less attention in policy and the media. In 2021 Defra set up the Lowland Agricultural Peat Task Force with Robert Caudwell - a South Lincolnshire farmer and Chairman of the Association of Drainage Authorities – at its helm to examine how to manage lowland agricultural peat more sustainably. At the end of June Defra published Caudwell’s report and agreed to all 14 of its main recommendations.

Lowland agricultural peat emits 3% of the UK’s entire territorial greenhouse gas emissions, according to the UK Centre for Ecology and Hydrology. When the water table is lowered on peat, soil conditions become aerobic. This stimulates microorganisms that decompose the accumulated plant matter and release its carbon as carbon dioxide. Extensive draining for agriculture and peat-cutting for fuel and horticulture has left less than 1% of English lowland peat soils in near-natural condition.

Stemming this carbon release requires rewetting the peat. Every 10cm increase in the height of the water, until it reaches 30cm below the ground surface, could reduce emissions of carbon dioxide by three tonnes per hectare per year. Methane emissions increase if the water table is raised too close to the surface, but a sweet spot for minimal net emissions exists when the water table lies between 10 and 30cm below the surface.

Tackling the greenhouse gas emissions from lowland agricultural peat will require innovation, compromise, and a long-term plan – not least to protect national food security, given that lowland agricultural peat makes up 20% of England’s Grade 1 land and 19% of its Grade 2 land. The Task Force was asked to “build consensus amongst farmers, conservationists, academics and other delivery partners” about how to extend the useable lifespan of lowland agricultural peat soils whilst reducing emissions and supporting profitable farming.

In his report, Caudwell is unambiguous that farmers on lowland agricultural peat cannot continue with business as usual. Even disregarding the harm to the climate from the current management regime, soil erosion and the increasing risk of drought on drained agricultural peat mean that farmers will need to rewet their soils to continue farming. Economically, the climate benefits of restoring all peatlands in England are 5-10x larger than the costs of rewetting them. However, Caudwell argues that the economics, methods, and wider impacts of wetter farming (‘paludiculture’) on lowland agricultural peat need to be better understood and de-risked before paludiculture can become mainstream. There must be a clear roadmap to build commercially viable paludiculture.

Caudwell begins his report by recommending that freshwater should be managed more holistically in the landscape – less should be flushed to sea and more should be stored on the land in wetlands, farm soils, and farm reservoirs. This would require new investment in water storage, management and control infrastructure, and new legal routes to allow water companies to invest in rewetting lowland peat.

Internal Drainage Boards (IDBs), which are instrumental in managing water levels in the Fens and other level areas, should have a larger role in peat restoration, Caudwell argues. He recommends that the government undertake a legal review of the implications of asking responsible authorities like IDBs to raise water levels for peat restoration. IDBs should also be empowered to own and operate infrastructure for irrigation and water storage, and receive grant funding rates. The government has committed to the proposed legal review, supports the creation of new IDBs, and supports transferring more responsibility to them.

Restoring peatlands so they stop haemorrhaging carbon is a public good. Caudwell recommends that Defra’s Environmental Land Management (ELM) schemes, particularly Countryside Stewardship (CS), should include incentives for activities that reduce peat-related emissions. He proposes a sliding payment scale depending on the height to which the water table is restored, and long-term payment commitments from government. In response, Defra has committed to exploring CS and Landscape Recovery as options for these payments, with possible Sustainable Farming Incentive (SFI) payments for peat soil monitoring. Caudwell further recommends that the government funds the creation of Peat Sensitive Farming Advisers, but Defra is still exploring options for knowledge dissemination.

Private investment (for example through carbon offset credits) will also be crucial to financing wetter farming. Better measurement, reporting and verification of lowland peat management techniques under different crop and water-management systems are needed to bring lowland agricultural peat into carbon markets, the report stresses. Version 2.0 of the IUCN’s Peatland Code, published in March, now covers lowland fen peat – but there is still a way to go to reduce transaction costs and increase confidence in these markets.

The report found that the maze of regulation regarding water management in the lowlands is a barrier to peat restoration and recommends a review of “current policy and legal frameworks” that obstruct or enable wetter ways of farming on peat. The government was more lukewarm on this recommendation and likewise on Caudwell’s tenth recommendation to assess the socioeconomic impacts of rewetting lowland peat. Defra’s response stated that aspects of each recommendation will be delivered through the previously announced Plan for Water and £6.6m paludiculture research budget.

Defra has already committed to updating its dataset on lowland peat – which is 35 years out of date – and will publish open-source maps in 2024. Caudwell recommends going further and ground-truthing peat condition. He notes many striking research gaps. We do not have a clear picture of how different grassland and horticultural management regimes affect carbon emissions on lowland peat. How effective is irrigation at reducing carbon emissions from peat? Do nitrous oxide emissions increase when rewetting nutrient-enriched peat soils? How much water currently pumped to sea could feasibly be stored on the land?

The government states that its £6.6m peat research programme, its £5.6 million Paludiculture Exploration Fund, and a two-year Environment Agency research project will answer some of these questions. Nevertheless, the number of urgent questions probably exceeds this budget.

Overall, Caudwell’s thorough report emphasises that a paradigm shift in farming on peat must occur but finds that the knowledge is not yet here for an immediate transition. It is therefore significant that Defra has now adopted the Task Force’s roadmap to commercially viable paludiculture – although many actions must happen outside government.

Perhaps the most important of these industry-led actions is to tell a coherent and honest story to consumers and food retailers about the emissions from lowland agricultural peat, and what wetter farming will look like.