Countryside Survey: Soils Report from 2007 www.countrysidesurvey.org.uk CS Technical Report No. 9/07 Soils Report from 2007 Emmett, B.A. 1, Reynolds, B. 1, Chamberlain, P.M. 2, 1 1 1 3 Rowe, E. , Spurgeon, D. , Brittain, S.A. , Frogbrook, Z. , 1 1 1 1 Hughes, S. , Lawlor, A.J. , Poskitt, J. , Potter, E. , 1 1 1 1 Robinson, D.A. , Scott, A. , Wood, C. , Woods, C. Centre for Ecology & Hydrology (Natural Environment Research Council) January 2010 1 Centre for Ecology & Hydrology, Maclean Building, Benson Lane, Crowmarsh Gifford, Wallingford, Oxfordshire, OX10 8BB 2 Formerly, Centre for Ecology & Hydrology 3 Formerly, Centre for Ecology & Hydrology; Now, Environment Agency, Wales 1 Countryside Survey: Soils Report from 2007 Acknowledgements The Countryside Survey of 2007 is funded by a partnership of nine government funded bodies led by the Natural Environment Research Council (NERC) and the Department for Environment, Food and Rural Affairs (Defra). The completion of the survey has only been made possible by the support and advice of many dedicated individuals from these and other organisations who provided their time and valuable advice to the project board, the project steering group, and the project advisory groups. The project Partners would like to thank all the landowners, farmers, and other land managers who gave permission for the field surveyors to collect data and samples from their land. Without such cooperation, scientific field studies like Countryside Survey would not be possible. The Countryside Survey Partners would like to thank all those who contributed to the work presented in this report, largely in NERC’s Centre for Ecology & Hydrology (CEH): Field surveyors, regional coordinators and QA teams: Nik Aspey, Boris Assyov, Maurice Bailey, Dave Bennett, Caroline Boffey, Katja Busch, Anne Butler, Luciana Carotenuto, Paul Chamberlain, Rebecca Chance, Jake Chant, Hannah Chivers, David Cole, Ceirios Davies, Kathryn Dawson, Jan Dick, Mitzi de Ville, Martin Duncan, Claire Edwards, Richard Ellis, Fiona Everingham, Angus Garbutt, Iain Gunn, Anne Harvey, Adrianna Hawczak, Stuart Hedley, Lynn Heeley, Gale Hodges, Nik Hudson, Sarah Hulmes, Gwilym Jones, Ursula Jones, Jana Kahl, Emma Koblizek, Wendy MacFarlane, Lindsay Maskell, Alain Mauric, Elaine McClymont, Sebastian Meis, Bruce Miller, Ruth Mitchell, Lindsay Moore, Lila Morris, Mike Morecroft, Owen Mountford, John Murphy, Emma Nicklin, Lisa Norton, Peter Nuttall, Judith O’Hare, Martin Page, Denise Pallett, Hristo Pedashenko, Jodey Peyton, Alison Pike, Hannah Price, Maria Ramirez-Jimenez, Amy Rees, Brian Reynolds, Nicola Rivett, Glenn Roberts, Liz Roberts, Patrick Home Robertson, Rob Rose, Martin Rossall, Ed Rowe, Frank Ryan, Stephen Ryder, Pete Scarlett, Dave Scott, Robert Seaton, Luke Sidebottom, Louise Slack, Simon Smart, Tom Smith, Jon Steele, Peter Steward, Michelle Taylor, Sam Thomas, Nicola Thompson, Will Thomson, Annie Truscott, Linda Turner, Jackie Ullyett, Kiril Vasilev, Katy Walker, Kevin Walker, Alistair Watson, Trevor West, James Whiteford, Michael Wilcox, Lorna Wilkie, Geoffrey Wilkinson, Claire Wood. Statistical, analytical, technical and data management support: Annie Brittain, Mike Brown, Paul Chamberlain, Kathy Chandler, Jackie Chaplow, Jenny Clapham, Ralph Clarke, Andy Crowe, Zoe Frogbrook, Steve Hughes, Alan Lawlor, Jan Poskitt, Elaine Potter, Annabel Rice, Phil Rowland, Andy Scott, Rod Scott, Rick Stuart, Nicola Thomson, Colin Vincent, Mike Wilson, John Watkins, Ruth Watts, Claire Wood, Clive Woods and Simon Wright. Advice and training: Colin Barr, Helaina Black, Bob Bunce, Zoe Frogbrook, Dave Howard, Mike Hornung, Steve Marshall, Steve Moss and Dave Wilson. Project management and administration: Mark Bailey, Mike Brown, Peter Carey, Julie Delve, Bridget Emmett, Les Firbank, Julie Grimshaw, Lindsay Maskell, John Murphy, Lisa Norton, Dan Osborn, Terry Parr, Ian Simpson, Simon Smart and John Watkins. 2 Countryside Survey: Soils Report from 2007 Contents Executive Summary p.4 1) Field Sampling and Bulk Density p.9 2) Carbon p.18 3) Soil pH p.43 4) Total nitrogen and C:N p.67 5) Mineralisable-N p.89 6) Olsen P p.108 7) Soil metal concentrations p.129 8) Soil invertebrates p.167 3 Countryside Survey: Soils Report from 2007 Executive Summary Executive Summary Countryside Survey is a unique study or ‘audit’ of the natural resources of the UK’s countryside. The Survey has been carried out at regular intervals since 1978. The countryside is sampled and studied using rigorous scientific methods, allowing us to compare results from 2007 with those from previous surveys. In this way we can detect the gradual and subtle changes that occur in the countryside over time. A series of reports have been published outlining the main findings for UK and individual countries which included results for two soil variables namely soil carbon and acidity. This report outlines the major findings for all soil variables measured as part of the survey in 2007. Key policy questions to be answered in 2007 were: • Can we confirm the loss of soil carbon (0-15cm) as reported by Bellamy et al . 2005? • Has the recovery from acidification detected by Countryside Survey in 1998 between 1978 and 1998 continued? • Can the trend of eutrophication of the countryside detected in the vegetation be detected in the soil using the mean total nitrogen concentration? • Can the trend of eutrophication of the countryside detected in the vegetation be detected in the soil as well using a more sensitive soil process method for nitrogen? • Can the trend of increasing P status in intensive grasslands be confirmed and is it matched in other habitats? • Is the decline in atmospheric deposition of heavy metals as reported by the Heavy Metals Monitoring Network reflected in soil metal concentrations measured in Countryside Survey? • Does Countryside Survey provide any evidence to indicate that there has been a loss of soil biodiversity as has been stated by the European Union? Soils have been part of Countryside Survey since it’s inception in 1978. The rationale for their inclusion was originally to provide many of the explanatory variables which contribute to the understanding of vegetation distribution and change which are the central core of the survey. More recently soils have been recognised as a valuable resource in their own right due to their importance for delivering a range of ecosystem services. Consequently the number of variables have increased over time from soil organic matter and pH in 1978, to nutrients, contaminants and biodiversity in 1998, and soil physical measurements and biogeochemical fluxes in the latest survey in 2007. The soil variables were selected for inclusion in the 2007 survey according to a range of criteria including: relevance to policy needs, scientific questions, uniqueness of Countryside Survey soils data both in isolation and when combined with other Countryside Survey variables, value for money and links and compatibility with other soil monitoring programmes. It should be noted that with the exception of soil invertebrates many Countryside Survey soil variables are currently included in the list of recommended primary indicators of soil quality by the UK Soil Indicator Consortium namely: soil organic matter, soil organic carbon, bulk density, soil acidity (pH), mean total nitrogen concentration, an indicator of phosphorus availability (Olsen-P), an indicator of nitrogen availability (mineralisable-N), total copper, zinc, cadmium and nickel. All variables with the exception of soil invertebrates are measured in the top 15cm of the soil profile only. Soil invertebrates are recorded for the top 8cm of soil. This focus on the top 15cm of soil mirrors the focus of several other soil monitoring programmes as it is thought the top soil horizons are the most susceptible to change over time as they are more immediately affected by land management activities and environmental change. Ideally future soil monitoring should include lower soil horizons as important stocks of carbon, supply of nutrients, filtering and storage of contaminants, and soil biota occur below the top 15cm. Countryside Survey uses a sampling approach which samples one-kilometre squares randomly located within different land class in GB. The original 1978 survey consisted of 256 1-km squares and collected five soil samples per square where possible, taken from random co-ordinates in five segments of the square. Detailed vegetation and other biophysical measurements were taken at the same location. In total, the 1978 survey collected 1197 soil samples for analysis. During 1998, surveyors collected soil samples from the plots used 4 Countryside Survey: Soils Report from 2007 Executive Summary for soil sampling in the original 1978 squares and 1098 samples were returned for analysis. Plots were re- located using maps and/or markers placed in the 1978 survey. In 2007, 591 1-km squares were sampled with a total of 2614 samples returned for analysis. More samples were therefore taken in 2007 than collectively in 1978 and 1998. This increase in sample over time has been driven by the requirement to provide individual country level reports first for Scotland in 1998 and then Wales in 2007. Statistical methods are used to enable this increase in sample number over time to be taken into account when estimating change over time. The limited number of sampling sites in Wales in 1978 and 1998 have limited the number of vegetation and soil categories where change can be reported. However, the data provides an important