Soil organic matter management across the EU – best practices, constraints and trade-offs
The aims and objectives of the report 'Soil organic matter management across the EU – best practices, constraints and trade-offs' are to assess the relative contributions of the different inputs and outputs of organic carbon and organic matter to and from the soil.
European soils store around 73 to 79 billion tonnes of carbon, which is more than 50 times the anthropogenic emissions of the 27 Member States of the European Union (4.6 billion tonnes of CO2-equivalent in 2009, excluding the LULUCF (land use, land use change and forestry) sector). Particularly important are peatland soils, as they store around 20-25% of the total soil carbon, whilst covering only 7% of the EU-27 surface area. Soil organic carbon stocks are dynamic and changes in land use, land management and climate all have significant impacts. The decline of soil organic carbon worldwide is an environmental risk that undermines not only soil fertility and productivity, and hence food security, but also the progressive stabilisation and subsequent reduction of atmospheric CO2 concentration levels.
Soil organic matter losses occur when grasslands, forests and natural vegetation are converted to cropland. The reverse is true if croplands are converted to grasslands, forests and natural vegetation. Land use changes can result in rapid carbon losses (i.e. instant), whereas gains accumulate more slowly (i.e. decadal). Different sources of organic matter have different assimilation and decomposition characteristics, and result in different soil organic matter fractions. If the rate of assimilation is less than the rate of decomposition, soil organic matter will decline and, conversely if the rate of assimilation is greater than the rate of decomposition, soil organic matter will increase. Like for land use changes, organic matter can be lost instantaneously (e.g. by fire), whereas its build up is spread over several decades.
The report quantifies the effect on soil organic matter or on the precursor to soil organic matter (i.e. humified organic carbon) of selected theoretical scenarios to the 2030 time horizon:
- The maintenance of grassland scenario examines the effect of grassland area changes on levels of soil organic carbon stock. The maintenance of grassland areas is related to the Good Agricultural and Environmental Condition (GAEC) standards for permanent pastures that are in place for farmers to adhere to if they want to receive benefits from the Single Farm Payment Scheme. In this scenario we compare the impact of abolishing restrictions on maintaining permanent pasture areas with maintaining the current rules.
- The use of set-aside scenario examines the implications of putting set-aside under arable or under different degrees of afforestation (it applies to EU-15 Member States only).
- The change from utilised agricultural area to forest scenario examines the effect on the soil organic carbon stock of converting agricultural land to forest at a higher rate (2% higher) than the current conversion rates. The scenario is related to agri-environmental measures that encourage farmers to convert agricultural land to forest.
- The use of crop residues and straw scenario examines the impact of the use and management of crop residues and straw on soil organic carbon fluxes. In this scenario we compare the effect of taking away from the field increasing amounts of crop residues and straw (10%, 30%, 50%) up to a worst case scenario whereby 100% of residues are harvested.
- The use of manure and compost scenario assesses the availability of organic carbon to agricultural land from manure produced by farms and compost produced from the urban waste.
- The use of forestry residues scenario examines the impact of different forest residue management options, with a particular focus on whether residues from branches and roundwoods that are removed from forests. In this scenario we consider the effect of removing 10% forest residues, 20% forest residues, 25% forest residues and 10% area stumps, and a worst case scenario whereby 70% of the wood residues and 25% of the stumps are removed.
The conservation of peatlands scenario assesses the factors that determine soil organic carbon stock and fluxes under peatlands and examines the impact of different options to conserve peatlands. We compare the effect of continuing peatland drainage with a 50% reduction and with a complete stop. In addition, we include a best case scenario that assumes that 25% to 100% of existing peatlands are restored by 2030.
The full report (without Annex II, available below) can be downloaded here (pdf ~ 6,64Mb).
The report is also available section by section:
- Executive Summary (pdf ~ 1Mb)
- Table of Contents, Figures, Tables, Boxes and Abbreviations (pdf ~ 90kb)
- Chapter 1 (Introduction), Chapter 2 (The role of soil organic matter in ecosystems and society) and Chapter 3 (Approach to assess regional soil organic matter balances and scenario analyses) (pdf ~ 1,26Mb)
- Chapter 4 (Maintenance of grassland), Chapter 5 (Use of set-aside) and Chapter 6 (Change from utilized agriculture area to forest) (pdf ~ 2,32Mb)
- Chapter 7 (Use of crop residues and straw), Chapter 8 (Use of manure and compost), Chapter 9 (Use of forest residues) and Chapter 10 (Conservation of peatlands) (pdf ~ 2,58Mb)
- Chapter 11 (Summary and conclusions of soil organic carbon stock and fluxes analysis), Chapter 12 (Identification of best practices in relation to soil organic matter management on the basis of selected case studies) and Chapter 13 (Recommendations) (pdf ~ 1Mb)
- References and Annex I-Description of LUMOCAP (pdf ~ 264kb)
- Annex II-Case studies (pdf ~ 3,3Mb)