Vulnerability of Organic Soils in England and Wales
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VULNERABILITY OF ORGANIC SOILS IN ENGLAND AND WALES Final technical report to DEFRA and Countryside Council for Wales DEFRA Project SP0532 CCW contract FC 73-03-275 Joseph Holden1, Pippa Chapman1, Martin Evans2, Klaus Hubacek3, Paul Kay1, Jeff Warburton4 1School of Geography, University of Leeds, Leeds, LS2 9JT. 2Upland Environments Research Unit, The School of Environment and Development, University of Manchester, Mansfield Cooper Building, Manchester, M13 9PL. 3Sustainability Research Institute, School of Earth and Environment, University of Leeds, LS2 9JT. 4Department of Geography, Durham University, Science Laboratories, South Road, Durham, DH1 3LE. February 2007 1 Contents 1. OBJECTIVES............................................................................................................................................................... 8 2. ORGANIC SOILS: CLASSIFICATION AND BASIC CHARACTERISTICS ................................................... 10 2.1 SUMMARY ................................................................................................................................................................. 10 2.2 METHODS USED ........................................................................................................................................................ 10 2.3. CLASSIFICATION, DEFINITIONS AND SPATIAL DISTRIBUTION........................................................................................ 10 2.4. PHYSICAL AND CHEMICAL PROPERTIES OF ORGANIC SOILS......................................................................................... 15 2.4.1. Physical properties ......................................................................................................................................... 15 2.4.2. Chemical properties........................................................................................................................................ 16 2.5 VEGETATION COVER AND LAND USE ........................................................................................................................... 16 2.6 IMPLICATIONS FOR THIS REPORT................................................................................................................................ 19 3. TYPES AND CAUSES OF DEGRADATION ......................................................................................................... 20 3.1 SUMMARY ................................................................................................................................................................. 20 3.2 METHODS................................................................................................................................................................. 20 3.3 INTRODUCTION ......................................................................................................................................................... 20 3.4 VULNERABILITY OF ORGANIC SOILS............................................................................................................................ 21 3.5 MONITORING OF EROSION AND ORGANIC SOIL LOSS BY WIND AND WATER .................................................................... 22 3.6. NATURAL AND ARTIFICIAL EROSION OF UPLAND ORGANIC SOILS................................................................................. 25 3.7 SIGNIFICANCE OF LANDSLIDES FOR ORGANIC SOIL DEGRADATION............................................................................... 27 3.8 ORGANIC SOIL SUBSIDENCE AND WASTAGE................................................................................................................. 29 3.9 DAMAGE TO ORGANIC SOILS CAUSED BY MINING......................................................................................................... 30 3.10 FOOTPATH EROSION AND RECREATIONAL IMPACTS ON ORGANIC SOILS ...................................................................... 30 3.11 SIGNIFICANCE OF CHANGING CLIMATE FOR THE DEGRADATION OF ORGANIC SOILS ................................................... 32 3.11.1 Summer drought............................................................................................................................................. 33 3.11.2 Increased summer and winter storminess...................................................................................................... 33 3.11.3 Changes in the growing season and vegetation............................................................................................. 33 3.12 ATMOSPHERIC DEPOSITION ..................................................................................................................................... 35 3.13 THE IMPACTS OF LIVESTOCK PRODUCTION............................................................................................................... 36 3.14 EFFECTS OF ARABLE FARMING................................................................................................................................. 37 4. FUNCTIONS OF ORGANIC SOILS ....................................................................................................................... 41 4.1 SUMMARY ................................................................................................................................................................. 41 4.2 METHODS................................................................................................................................................................. 41 4.3 OVERVIEW ................................................................................................................................................................ 41 4.4 HYDROLOGY ............................................................................................................................................................. 41 4.4.1 River flow......................................................................................................................................................... 42 4.4.2 Hillslope hydrology.......................................................................................................................................... 42 4.4.3 Sediment and pollutants................................................................................................................................... 44 4.5 AGRICULTURAL PRODUCTION.................................................................................................................................... 45 4.5.1 Livestock farming............................................................................................................................................. 45 4.5.2 Arable farming................................................................................................................................................. 46 4.5.3 Grouse ............................................................................................................................................................. 46 4.5.4 Forestry ........................................................................................................................................................... 46 4.6 BIODIVERSITY AND GEODIVERSITY RESERVOIRS .......................................................................................................... 47 4.7 ARCHAEOLOGICAL PRESERVATION ............................................................................................................................. 50 4.8 TOURISM, LEISURE AND EDUCATION .......................................................................................................................... 51 5. STATE OF ORGANIC SOILS IN ENGLAND AND WALES............................................................................... 52 5.1 SUMMARY ................................................................................................................................................................. 52 5.2 METHODS................................................................................................................................................................. 52 5.3 INTRODUCTION ......................................................................................................................................................... 52 5.4 ESTIMATING THE TOTAL LOSS OF ORGANIC SOIL FROM UPLAND PEAT ENVIRONMENTS .................................................. 52 5.5 PEAT HARVESTING..................................................................................................................................................... 58 5.6 DRAINAGE ................................................................................................................................................................ 59 5.7 BURNING .................................................................................................................................................................. 60 5.8 LIVESTOCK GRAZING (INCLUDING LIMING)................................................................................................................. 63 5.9 AFFORESTATION ....................................................................................................................................................... 66 5.10 ATMOSPHERIC POLLUTION ...................................................................................................................................... 68 5.10.1 Heavy metals.................................................................................................................................................