1、Carbon Sequestration in European Agricultural Soils by 2010 - Potential, Uncertainties, Policy Impacts,Annette Freibauer afreibbgc-jena.mpg.de Mark D. A. Rounsevell Pete Smith Jan Verhagen,UCL,Vleeshouwers & Verhagen, GCB 2002,C fluxes in SOC in the 1st commitment period: BAU,t C ha-1 y-1,Cropland m
2、ean flux: +0.83 (0.40) t C ha-1 y-1 (source) Total in EU-15: 77 (37) Tg C y-1,Grassland mean flux: -0.60 (0.65) t C ha-1 y-1 (sink?) Total in EU-15: -30 (32) Tg C y-1,Total agricultural soils Total in EU-15: 48 (37) Tg C y-1 (source),Most promising measures,1 Promote organic input on arable land ins
3、tead 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 components3 Biofuel production with short-rotation coppice plantations and perennial gr
4、asses on arable set-aside land4 Promote organic farming5 Promote permanently shallow water table in farmed peatland6 Zero tillage / conservation tillage,Cropland,Grassland,Peatland,Potential per unit area,Uncertainty: spatial variability, soil and climate types; no human components,Factors limiting
5、carbon sequestration,Sink saturationNon-permanenceAvailability of land and resourcesAdoption of measures / contiguous?,Area and resources available,total area limitations suitable area million ha million ha Cropland 73more organic input organic material 60?reduced tillage climate, soil 63?extensific
6、ation, perennials set-aside land 7.3bioenergy crops set-aside land 7.3organic farming now 2% of cropland 7Grassland (in rotation) 8.4 longer duration of leys no need: set-aside 7.3from leys to permanent grass no need: set-aside 7.3Peatland in agriculture 3.6restoration of drained soil highly product
7、ive 1-2Ramsar, CBD!,Uncertainty: adoption rate, adoption time?,Cropland,Grassland,Peatland,Feasible Potential in EU-15,Uncertainty: spatial variability, adoption, permanence of adoption,Environmental effects,Tillage Amendments Extensif. PeatlandHerbizides, pestizidesNon-CO2 gasesNH3, NOxBiodiversity
8、Water qualitySoil qualitySustainable land management,Productivity?,?,?,?,?,Farm income,Organic amendments positive long-term, easy, cheap Bioenergy crops region-specific, emerging markets Organic farming region-specific, emerging marketsReduced tillage region-specific, risks, long-term benefitsExten
9、sification 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
10、provide better quantification?,Policy impacts,Putting C sequestration options into a real-world context influenced by policy,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
11、and set-aside A wealth of rural development and agri-environmental policies,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 (ara
12、ble area, agri-environment) - change in permanent crop production systems - maintenance of meadows in LFA - forestation of agricultural land,Conclusions (1),Policy changes post 1990 have probably had an overall +ve effect on C sequestration But, uncertainties surround the effects of some policies (L
13、FAs, 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,Conclusions (2): Caveats,C balance in grasslands?
14、What measures are best adjusted to regional management preferences?Regional land use / land management historyRegional best practicePermanent, contiguous, long-term adoption of measures?Monitoring!Costs?Regional modelling for potential, adoption, income necessaryRegional refinement of policy measure
15、s necessary,Availability of land and resources / potential,Soil carbon sequestration (Mt CO2 y-1) Measure Limiting factor Theoretical Technical Economic?all agric. Given feasibleland used limitation by 2012 Cropland Zero-tillage Suitable land = 63 Mha 103 89.28 8.93 Reduced-tillage Suitable land = 6
16、3 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 s
17、traw = 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,Extensificati
18、on 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,Availability of land and resources / potential,Soil carbon sequestration (Mt CO2 y-1) Measure Limiting factor Theoretical Technical Economic?all agric. Given fea
19、sibleland used limitation by 2012 Grassland ? Knowledge! ? ? ?,RevegetationAbandoned arable land current set-aside = 7.3 Mha 165 16.52 Max. 16.52,Land conversionArable 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 La
20、nd-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,Availability of land and resources / potenti
21、al,Soil carbon sequestration (Mt CO2 y-1) Measure Limiting factor Theoretical Technical Economic?all agric. Given feasibleland 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
22、 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 meliorationis needed = 50 % of grass- 36 GHG: 36 15 15 land area = 1.5 MhaConvert arable to grassland No incentive 3 GHG: 3 0? 0? Convert arable Subsidies compensate inc
23、ome to woodland losses: adoption rate max. 2 GHG: 3 1 1 50 % of arable area = 0.3 Mha,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,
