Lowland peatlands

Lowland peatlands are distributed across much of the UK. Most lowland peatlands have been drained, creating some of the highest grade arable and horticultural land in the UK, however drainage also exposes previously waterlogged organic matter to decomposition and compaction, leading to long-term subsidence and sustained CO2 emissions.

Lowland peatlands, comprising lowland raised bogs and fens, are distributed across much of the UK. Some of the most extensive lowland peat areas occur in the East Anglian Fens, Somerset Levels and in the lowlands of Northern England, although they are also widespread in Scotland, Northern Ireland and Wales. The overwhelming majority of the UK’s lowland peatlands have been drained for cultivation, creating some of the highest grade arable and horticultural land in the UK, but simultaneously exposing previously waterlogged organic matter to decomposition and compaction, leading to long-term subsidence and sustained CO₂ emissions.

We now have a robust empirical basis from which to estimate average GHG emissions from lowland peats across a range of broad land-management categories. In previous projects, we have established a network of state-of-the-art ‘flux tower’ systems to measure GHG emissions from a range of lowland peat sites under different forms of management, and are continuing to expand this network within the project. The flux tower network is helping us to quantify GHG emissions, study how they are affected by land-use, and over time to improve our understanding of how these emissions are affected by year-to-year variations in weather conditions, such as summer droughts, as well as the effects of crop type and farming activities such as ploughing and harvesting.

Despite our improving understanding of lowland peatlands, we still need to answer some important questions. Firstly, although we can compare sites under different management, we have not yet been able to measure what happens to emissions when the management of a site changes, for example by raising water levels. Secondly, before policy decisions are made on how best to mitigate GHG emissions from lowland peatlands, it is vital to understand what impact higher water levels will have on food production. For example, how far can water levels be raised (and at what time of year) before this starts to have detrimental impacts on crop yields and farm incomes? To answer these questions, we are establishing a large field experiment that will test the effects of changing water levels on GHG emissions, soil quality, crop yield and disease resistance within a typical horticultural field. The results of this study will help to inform government policy on the future management of lowland peatlands throughout the UK.