Farmers and conservationists are pioneering ways to reduce the environmental impact of farming on peat, as pressure mounts to cut emissions from UK peatlands.
And there are calls for funding focused on peatlands to help farmers switch to more sustainable systems.
Lowland agricultural crop and grassland peat soils which have been drained, ploughed and fertilised account for more than half of the 23 million tonnes of annual carbon dioxide emissions from UK peatlands, analysis led by the UK Centre for Ecology and Hydrology (UKCEH) estimates.
Jack Clough, from the University of East London’s Sustainability Research Institute, said where carbon-rich peatlands have been drained, microbes convert peat to carbon dioxide in the presence of oxygen, “literally turning peat into thin air”.
The peat is disappearing at the rate of around 1-3cm a year, and where the water table is well below the surface – typically around 40-100cm – because of drainage, it produces around 25-40 tonnes of carbon dioxide per hectare a year, he said.
Soil scientist-turned farmer Stephen Briggs, who farms on peat and clay in Cambridgeshire in East Anglia’s productive fens, said: “The only way to completely stop peat degradation, from losing these peat soils, and completely reducing carbon emissions is to stop farming them and to reflood them.”
But that has implications for livelihoods, the economy and food security, he added.
“There’s always going to be compromise, trying to find ways of farming and managing the land that reduces as far as practical the further oxidation and degradation of peat soils whilst still being productive,” he said.
While the internal drainage board controls the local water table, Mr Briggs, who is a member of the Nature Friendly Farming Network (NFFN) and sits on the Environment Department (Defra) Lowland Agricultural Peat Task Force, is taking steps to prevent water loss and protect soils.
His organic agroforestry system has rows of fruit trees with wildlife-friendly plants running through the fields with conventional crops such as barley, wheat, and vegetables in between.
The trees act like hedges to slow down wind and evaporation, avoiding artificial pesticides and fertilisers improves soil structure and “companion” crops such as clover grown under the main crops keeps carbon cycling through the soil, he said.
Soil health on his farm has improved, wildlife has increased, the fruit trees are locking up carbon and the land is more productive per hectare, Mr Briggs said.
Mr Briggs said a package of solutions was needed for farming on peat, adding: “There should be a separate innovation fund to allow farmers to try things at a small scale”, in addition to the new agricultural payments programme.
Just a few miles from Mr Briggs’ farm, the Water Works project by Bedfordshire, Cambridgeshire and Northamptonshire (BCN) Wildlife Trust is trialling a more radical solution which involves reflooding the land while maintaining productive farming.
The wet farming or paludiculture experiment, funded by the People’s Postcode Lottery, has created test beds where the water table will be kept to within 10cm of the surface to prevent carbon loss.
Crops including bulrush, which could be used for insulation, and sweet manna grass – a gluten-free grain – as well as novel crops including wild celery, yellow flag iris and meadowsweet, with uses including food, medicine, and gin flavourings, were planted last year.
The crops have all survived the very wet winter and dry April, although local Chinese water deer treated the flag iris as a salad bar, BCN Wildlife Trust’s Kate Carver said.
Sphagnum moss, which has multiple potential uses, including as a substitute for peat in vegetable growing and gardening, is being planted this summer.
Ms Carver said: “Through our field-scale trials and monitoring programmes, we aim to prove that wet farming can prevent the loss of carbon, prevent the loss of peat soils, clean water, and support wildlife.”
The scheme aims to demonstrate wet farming crops could be grown on a “real life” fenland farm and offer new opportunities to farmers, with the potential to ripple out over the wider fens, she said.
Mr Clough, with colleagues, is monitoring the carbon emissions, soil surface levels and water table at the Water Works scheme.
He said research showed each 10cm increase in the water table could reduce emissions from the peat soils by around three tonnes per hectare per year, although it needed to rise to the levels seen in paludiculture to largely halt them.
There is also evidence that some conventional crops could grow in soils with higher water levels, although more research is needed to assess the trade-offs, such as lower yields, he said.
Raising the water table on conventional farming could buy time to develop paludiculture or other solutions such as a “carbon farming” markets which pay farmers specifically to protect the carbon in their land.
“I think paludiculture can play a valuable role now, but in the short term some sort of environmental payment or subsidy will help it take off.
“There is real potential for public and private finance to expand paludiculture, which will make a positive difference to the way we manage our peat,” he said.
A Defra spokesperson said its lowland agricultural peat task force was looking at how farmed peatlands could be better managed both to reduce greenhouse gas emissions and to safeguard continued profitable agriculture.
“The group is co-ordinating work already under way and exploring new solutions, including innovative ways to manage peatland water-table levels.”