Carbon Sequestration in EU Agricultural Soils: Potential, Uncertainties, Policy Impacts

1. UCL Carbon Sequestration in European Agricultural Soils by 2010 - Potential, Uncertainties, Policy Impacts Annette Freibauer [afreib@bgc-jena.mpg.de] Mark D. A. Rounsevell Pete Smith Jan Verhagen

2. Grassland mean flux: -0.60 (0.65) t C ha-1 y-1 (sink?) Total in EU-15: -30 (32) Tg C y-1 C fluxes in SOC in the 1st commitment period: BAU t C ha-1 y-1 Cropland mean flux: +0.83 (0.40) t C ha-1 y-1 (source) Total in EU-15: 77 (37) Tg C y-1 Total agricultural soils Total in EU-15: 48 (37) Tg C y-1 (source) Vleeshouwers & Verhagen, GCB 2002

3. Most promising measures 1 Promote organic input on arable land instead of grassland (crop residues, cover crops, FYM, compost, sewage sludge) 2 Permanent revegetation of arable set-aside land (e.g. afforestation) or extensivation of arable production by introduction of perennial components 3 Biofuel production with short-rotation coppice plantations and perennial grasses on arable set-aside land 4 Promote organic farming 5 Promote permanently shallow water table in farmed peatland 6 Zero tillage / conservation tillage

4. Potential per unit area Cropland Grassland Peatland Uncertainty: spatial variability, soil and climate types; no human components

5. Factors limiting carbon sequestration • Sink saturation • Non-permanence • Availability of land and resources • Adoption of measures / contiguous?

6. Area and resources available total area limitations suitable area million ha million ha Cropland 73 more organic input organic material ~60? reduced tillage climate, soil 63? extensification, perennials set-aside land 7.3 bioenergy crops set-aside land 7.3 organic farming now 2% of cropland 7 Grassland (in rotation) 8.4 longer duration of leys no need: set-aside 7.3 from leys to permanent grass no need: set-aside 7.3 Peatland in agriculture 3.6 restoration of drained soil highly productive <1-2 Ramsar, CBD! Uncertainty: adoption rate, adoption time?

7. Feasible Potential in EU-15 Cropland Grassland Peatland Uncertainty: spatial variability, adoption, permanence of adoption

8. Environmental effects Tillage Amendments Extensif. Peatland Herbizides, pestizides Non-CO2 gases NH3, NOx Biodiversity Water quality Soil quality Sustainable land management ? ? ? ? Productivity?

9. Farm income Organic amendmentspositive long-term, easy, cheap Bioenergy crops region-specific, emerging markets Organic farming region-specific, emerging markets Reduced tillage region-specific, risks,long-term benefits Extensification region-specific, compensation payments? Peatland restoration region-specific, compensation payments? • Judgements about farm incomes are always qualified by location – we cannot generalise! • different soil types, climates and farm structures • A modelling approach to address this problem and to provide better quantification?

10. Policy effects (post 1990) C sequestration potential Land use change Other effects Policy impacts Putting C sequestration options into a real-world context influenced by policy

11. Policy changes post 1990 • Radical changes in the structure of the CAP driven by the 1992 MacSharry reforms and Agenda 2000 • From production-based price support to area payments and set-aside • A wealth of rural development and agri-environmental policies

12. Policy effects on land use • Market support (intervention, import duties) that maintain producer prices • Production controls - quota: number of dairy cows declining - set aside: C sequestration,biofuels • Direct aid payments (arable area, agri-environment)- change in permanent crop production systems- maintenance of meadows in LFA- forestation of agricultural land

13. Conclusions (1) • Policy changes post 1990 have probably had an overall +ve effect on C sequestration • But, uncertainties surround the effects of some policies (LFAs, NVZs, organic) and their impacts on farm incomes • Policy could contribute further to soil C sequestration in Europe • Further research should target policy as well as management options, be geographically explicit and tackle impacts on farm incomes

14. Conclusions (2): Caveats C balance in grasslands? What measures are best adjusted to regional management preferences? Regional land use / land management history Regional best practice Permanent, contiguous, long-term adoption of measures? Monitoring! Costs? Regional modelling for potential, adoption, income necessary Regional refinement of policy measures necessary

16. Availability of land and resources / potential Soil carbon sequestration (Mt CO2 y-1) Measure Limiting factor Theoretical Technical Economic? all agric. Given feasible land used limitation by 2012 Cropland Zero-tillage Suitable land = 63 Mha 103 89.28 8.93 Reduced-tillage Suitable land = 63 Mha < 103 <89.28 <8.93 Set-aside <10% of arable; < 7.3 Mha 103 Max = 8.93 0 Perennial grasses and permanent crops No incentives to grow more 165 0? 0? Deep-rooting crops Research and breeding needed for annual crops 165 0? 0? Animal manure Manure avail. = 385 Mt dm y-1 100 86.83 ? Crop residues Surplus straw = 5.3 Mt dm y-1 185 90.46 ? Sewage sludge Sewage sludge = 71 Mt dm y-1 69 6.30 ? Composting Compost available at present = 160 t dm y-1 (8 M ha) 100 11 11? Improved rotations 0 >0 0? Fertilisation 0 0 0 Irrigation 0 0 0 Bioenergy crops only current set-aside = 7.3 Mha 165 16.52 3.3 Extensification current set-aside to extensify 30% of arable agr. = 20 Mha 144 41.63 ? Organic farming Could increase to 10% = 7.3 Mha 0-144 14.40 14.4

17. Availability of land and resources / potential Soil carbon sequestration (Mt CO2 y-1) Measure Limiting factor Theoretical Technical Economic? all agric. Given feasible land used limitation by 2012 Grassland ? Knowledge! ? ? ? Revegetation Abandoned arable land current set-aside = 7.3 Mha 165 16.52 Max. 16.52 Land conversion Arable to woodland current set-aside = 7.3 Mha 165 16.52 Max. 16.52 Arable to grassland current set-aside = 7.3Mha 140 14 0 Grassland to Land-use change since 1990 arable calculated as 2.7 Mha -266 -10 (since 1990) Future = 0 Permanent crops Land-use change since 1990 to arable calculated as 0.4 Mha -42.5 -1.46 (since 1990) 0 Woodland to Negligible land-use change arable since 1990 =>-266 0 0

18. Availability of land and resources / potential Soil carbon sequestration (Mt CO2 y-1) Measure Limiting factor Theoretical Technical Economic? all agric. Given feasible land used limitation by 2012 Farmed organic soils Protection and Assuming all cultivated restoration organic soils are restored >36 >36 >36 Avoid row crops and tubers No incentive 0 GHG: 2 0? 0? Avoid deep ploughing No incentive 3 GHG: 3 0? 0? More shallow Possibly attractive on grass- water table land when new melioration is needed = 50 % of grass- 36 GHG: 36 15 15 land area = 1.5 Mha Convert arable to grassland No incentive 3 GHG: 3 0? 0? Convert arable Subsidies compensate income to woodland losses: adoption rate max. 2 GHG: 3 1 1 50 % of arable area = 0.3 Mha

19. Non-CAP effects • Technological change (plant & animal breeding) • World markets & international trade agreements • Changing consumer preferences – less meat, shifts from olive to sunflower oil, etc. • Opportunity costs of labour, i.e. competition with other sectors • Land degradation (e.g. erosion) • Irrigation water availability and quality • Education and information dissemination