Managing UK upland peat for greenhouse gas removal

Much of UK upland peat is in a drained and/or degraded state, meaning it is a net source of CO₂ emissions to the atmosphere. Typical restoration methods, such as rewetting, can improve this, however most restoration projects only achieve a lowering or cessation of emissions with few achieving a net-negative carbon balance. In this new demonstrator project, Greenhouse Gas Reduction – Peat, we are trialling methods of supressing methane emissions as well increasing carbon sequestration so that carbon negative restoration projects can be achieved.

The projects aims to accelerate the transition from degraded, burn-managed heather (Calluna vulgaris) bog to actively peat-forming bog, while minimising wildfire risk and CH4 emissions. We will present preliminary results and further plans for three techniques, trialled alongside typical gully blocking:

1) Sphagnum planting: This ‘nature-based’ intervention will involve Sphagnum (a peat forming moss species) establishment using micropropagated assemblages of hummock-forming species which show the highest rates of C accumulation. During the first years of Sphagnum growth, CO2 sequestration may be in excess of long-term peat accumulation rates as a functional upper ‘acrotelm’ layer re-establishes. Sphagnum can also act as a CH4 biofilter, improving the net greenhouse gas balance.

2) Heather mowing and biochar production: As an alternative to managed burning, we will harvest old heather biomass using low-ground pressure vehicles, followed by biochar production and re-application. Biomass removal will reduce wildfire risk, while controlled pyrolysis will avoid damage to Sphagnum/peat from burning, and enhance biomass conversion to biochar above that achieved in uncontrolled burns.

3) Suppression of methane production: CaSO4  can supress methane formation by offering a more energetically favourable metabolic pathway to microbes, meaning sulphate reducing bacteria are more active than methanogenic bacteria. This essentially ‘nudges’ the bacterial population in a direction more favourable for greenhouse gas balances.