CR-LU4
Sustainability Committee
Inquiry into Carbon Reduction in Wales: Rural Land Use Management and Carbon Reduction
Response from: Centre for Ecology and Hydrology, Bangor
This response addresses Question 5b as this lies within the area of expertise of staff at the Centre for Ecology and Hydrology, Bangor.
Carbon storage
Soils represent one of the largest stores of terrestrial carbon and appropriate soil management is crucial to maintaining and enhancing these stocks to avoid the deleterious consequences of the release of carbon to the atmosphere. Consideration of this issue requires that effective policy is built on sound scientific evidence. In that respect there are scientific data and techniques available to Wales for assessing changes in soil carbon over time and for predicting the likely outcomes of future management scenarios. This information can be used to underpin a number of policy-related opportunities which are available to the Welsh Assembly Government to ensure that rural land managers correctly perform the important task of managing soil carbon.
Science base
1) ECOSSE project. This large collaborative project was funded jointly by the Welsh Assembly Government and the Scottish Office and provides an in-depth study of the carbon dynamics of organo-mineral soils (mineral soils with a peaty surface layer) which are widespread in Wales. The study included a re-assessment of the carbon stocks held in these soils using a variety of data and modelling sources and explored the implications for soil carbon of various management options through a combination of desk, field and laboratory studies. A key outcome from the project was the development of a new computer model for predicting the response of soil carbon to a variety of environmental drivers such as land use and climate change.
The project results should be used to provide scientific underpinning for policy development in the management of carbon-rich soils in Wales. Project report: http://www.scotland.gov.uk/Publications/2007/03/16170508/0
2) Countryside Survey 2007 (CS2007). Countryside Survey (CS) is an approximately decadal audit of the countryside of Great Britain which started with the first survey in 1978. Each survey involves synchronous measurements of a wide range of biodiversity, landscape, freshwater and soil attributes focussed on 1 km sample squares across the British countryside. Soil pH and carbon concentration (0-15 cm depth) were measured in 1978, 1998 and again in 2007 when a more extensive range of analytes was also determined. This included concentrations of heavy metals, mineralisable and total nitrogen, soil microbial diversity, soil invertebrate diversity and available phosphorus. Approximately 600 squares were surveyed in CS2007 which for the first time provides sufficient data for statistically robust reporting of attributes at the individual country level. Soil carbon concentration and bulk density to a depth of 15 cm were measured in all squares sampled in 2007. These data can therefore provide a robust measurement baseline of soil carbon concentration (g/kg) and stock (t/ha) at 0-15 cm depth against which to assess future changes in soil carbon in Wales. Due to the statistical design of CS, it is possible to report attributes in a variety of ways relevant to policy makers including, for example, by individual Broad Habitat, environmental zone or soil type etc.. The integrated nature of the measurements also provides great power to the interpretation of results.
The first phase of reports from CS2007 will be launched on November 18th 2007 and will provide information for Great Britain as a whole. For carbon the reports will include an assessment of change in carbon concentration across the three surveys for each of the major Broad Habitats as well carbon stock (0-15 cm) for 2007.
A report for Wales should be published in 2009. Where sample numbers allow, it will be possible to report retrospectively on changes in soil carbon concentration at 0-15 cm for some Broad Habitats in Wales using data from the three surveys. CS2007 was funded by a range of agencies including Welsh Assembly Government and the Centre for Ecology and Hydrology.
Countryside Survey website: http://www.countrysidesurvey.org.uk/
Policy actions
1) Welsh soils action plan. This document should provide a focus for policy action on soils particularly in relation to management for carbon and should be included in any consideration of rural land management and carbon. Implementation of the relevant parts of the action plan is an obvious opportunity to make progress in soil carbon management in Wales.
2) Cross-compliance. This provides a practical mechanism for ensuring that farmers manage land in way that maintains or preferably enhances soil carbon stocks. A review of the measures relating to soil carbon management and an audit of compliance might provide a useful basis for assessing progress towards carbon targets for Wales.
3) Local action. There are a variety of practical actions that can be undertaken by land managers at the local scale to maintain and / or enhance soil carbon stocks. These include, for example, maintenance of wetland and peatland areas and planting of farm woodlands. There is an opportunity for Welsh Assembly Government to use the revisions of agri-environment schemes to include measures which will provide an incentive to land managers to maintain and enhance soil carbon stocks. Additional benefits may accrue where schemes can operate across several holdings together as it is then possible to manage natural landscape units, such as an extensive peatland, which may cross ownership boundaries.
4) Forest soils. Appropriate management of forest and woodland soils including those within commercial plantations should also be considered. In particular it is important that woodland carbon accounting includes appropriate assessment of changes in soil carbon stocks throughout the forest management cycle and not simply focus on carbon accrued by growing biomass.
5) Land management change. Soil carbon stocks are often vulnerable to change during conversion from one form of land management to another. For example, the effect on soil carbon of the conversion of grassland to forest on organo-mineral soils was specifically considered during the ECOSSE project. An area of current uncertainty lies in the implications for soil carbon of the conversion of coniferous woodland estate to wind farms. As far as we are aware, good data are lacking to account for the full carbon budget of this land use transformation which must address soil carbon losses particularly where peaty soils are exposed to drying and erosion.
Prof B Reynolds
Centre for Ecology and Hydrology
Environment Centre Wales
Deiniol Road
Bangor
Gwynedd LL57 2UW
