Literature Review: Defra Project SP1218 An assessment of the potential for paludiculture in England and Wales Authors: Dr Barry Mulholland, ADAS, Boxworth, UK Islam Abdel-Aziz, ADAS, Boxworth, UK Richard Lindsay, Sustainability Research Institute, University of East London, UK Dr Niall McNamara, UKCEH, Lancaster, UK Dr Aidan Keith, UKCEH, Lancaster, UK Professor Susan Page, School of Geography, Geology and the Environment, University of Leicester, UK Jack Clough, Sustainability Research Institute, University of East London, UK Ben Freeman, Bangor University, UK Professor Chris Evans, UKCEH, Bangor, UK April 2020 Contents EXECUTIVE SUMMARY ............................................................................................................................ 5 1 INTRODUCTION .................................................................................................................................... 8 1.1 History of Peatland Agriculture in the United Kingdom ............................................................. 8 1.2 Extent and Status of Lowland Peatlands in the United Kingdom ............................................... 9 1.3 Peatland Rewetting .................................................................................................................... 10 1.4 Paludiculture ............................................................................................................................... 11 2 PRODUCTIVITY AND SUITABILITY OF LAND FOR PALUDICULTURE .................................................... 13 2.1 Wetland Productivity ................................................................................................................. 13 2.2 Wetland Plants ........................................................................................................................... 14 2.3 Land Suitability for Paludiculture .............................................................................................. 15 3 OPTIONS FOR PALUDICULTURE.......................................................................................................... 18 3.1 Paludiculture and the Growing Media Industry ........................................................................ 18 3.1.1 Peat Extraction & Consumption in the UK ............................................................................... 18 3.1.2 Sphagnum Farming as a Growing Media Constituent ............................................................. 20 3.1.2.1 Sphagnum Farming in Germany ....................................................................................... 20 3.1.2.2 Sphagnum Farming in the UK ........................................................................................... 21 3.1.2.3 Practical Challenges for Sphagnum Farming .................................................................... 22 3.1.2.4 Economic Considerations .................................................................................................. 23 3.2 Paludiculture for Bioenergy ....................................................................................................... 25 3.2.1 Potential Bioenergy Crops from Paludiculture ........................................................................ 25 3.2.1.1 Suitability of Tree Species within a Paludiculture Context ................................................ 25 3.2.1.2 Potential of Non-Tree Species in a Paludiculture Context ................................................. 26 3.2.2 Characteristics of Key Crops ..................................................................................................... 27 3.2.2.1 Phragmites australis (Common Reed) ............................................................................... 27 3.2.2.2 Typha latifolia (Cattail/Bulrush/Reedmace) ..................................................................... 29 3.2.2.3 Miscanthus x giganteus ..................................................................................................... 30 3.2.3 Paludiculture and Solar Power ................................................................................................. 32 3.3 Paludiculture for Food Production............................................................................................. 32 3.3.1 Wetland Crops .......................................................................................................................... 32 3.3.2 Litter, Fodder and Grazing ....................................................................................................... 33 3.3.3 Fisheries ................................................................................................................................... 35 3.4 Other Potential Paludiculture Products..................................................................................... 35 3.4.1 Alternative Uses for Sphagnum ............................................................................................... 35 3.4.2 Other Medicinal Crops ............................................................................................................. 36 3.4.3 Use of Paludiculture Crops in Construction Materials ............................................................. 36 2 3.4.3.1 Traditional Uses ................................................................................................................. 36 3.4.3.2 Novel Uses ......................................................................................................................... 37 3.4.4 Use of Paludiculture Crops in Fabrics ....................................................................................... 38 4 GHG EMISSIONS/REMOVALS AND ASSOCIATED IMPACTS OF PALUDICULTURE ............................... 40 4.1 Estimation of Direct GHG Emissions and Removals .................................................................. 40 4.1.1 Carbon Dioxide and Methane .................................................................................................. 40 4.1.1.1 Emissions Calculator .......................................................................................................... 43 4.1.2 Nitrous Oxide ........................................................................................................................... 44 4.2 Indirect GHG Emissions and Removals ...................................................................................... 45 4.2.1 GHG Mitigation Potential of Bioenergy ................................................................................... 45 4.2.1.1 Biomass Data .................................................................................................................... 46 4.2.1.2 Harvesting Machinery and Diesel Consumption ............................................................... 46 4.2.1.3 Transport and Processing .................................................................................................. 46 4.2.1.4 Conversion Efficiencies and Realised Energy Yields........................................................... 47 4.2.1.5 Potential CO2 Savings ........................................................................................................ 48 4.3 Peat Subsidence.......................................................................................................................... 48 4.3.1 Subsidence Calculator .............................................................................................................. 49 4.4 Water and Energy Use ................................................................................................................ 50 4.4.1 Water Fluxes under Conventional and Paludiculture Management ....................................... 50 4.4.2 Energy use and Associated GHG Emissions due to Pumping ................................................... 52 4.4.3 Energy use and Associated GHG Emissions due to Surface Irrigation ..................................... 53 4.4.4 Practical Considerations for Water Management ................................................................... 54 5 POTENTIAL CO-BENEFITS OF PALUDICULTURE .................................................................................. 55 5.1 Ecosystem Service Benefits ........................................................................................................ 55 5.1.1 Direct Biodiversity Benefits from Paludiculture ....................................................................... 60 5.1.2 Indirect Biodiversity Gains from Paludiculture ........................................................................ 62 5.1.3 Flood Risk ................................................................................................................................. 64 6 BARRIERS AND INCENTIVES FOR PALUDICULTURE ............................................................................ 66 6.1 Barriers to Transition.................................................................................................................. 66 6.1.1 Water Management ................................................................................................................. 66 6.1.2 Weed Control ........................................................................................................................... 67 6.1.3 Mechanisation and Scale ......................................................................................................... 67 6.1.4 Trafficability ............................................................................................................................