Carbon Sequestration in European Agricultural Soils by 2010 by dennishaskins

VIEWS: 21 PAGES: 19

									 Carbon Sequestration in European
   Agricultural Soils by 2010 -
     Potential, Uncertainties,
          Policy Impacts


          Annette Freibauer
         [afreib@bgc-jena.mpg.de]
           Mark D. A. Rounsevell
UCL              Pete Smith
                Jan Verhagen
C fluxes in SOC in the 1st commitment period: BAU




                                                         t C ha-1 y-1


Cropland                                           Grassland
mean flux: +0.83 (0.40) t C ha-1 y-1 (source)      mean flux: -0.60 (0.65) t C ha-1 y-1 (sink?)
Total in EU-15: 77 (37) Tg C y-1                   Total in EU-15: -30 (32) Tg C y-1


                            Total agricultural soils
                            Total in EU-15: 48 (37) Tg C y-1 (source)

                                                              Vleeshouwers & Verhagen, GCB 2002
                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
                                     Potential per unit area
                    .
                    0
                    6

                                 O
                                 C
                                 2
                    .
                    0
                    5            H
                                 C
                    3
                    .
                    0            4
                                 O
                                 N
t C-equ. ha-1 y-1
                                 2
                    .
                    5
                    2
                    .
                    0
                    2
                    .
                    5
                    1
                    .
                    0
                    1
                    .
                    5
                    0
                    .
                    0
                    0
                0
                -
                .5
                       t i oc f
                       ulei gprn g n as
                       pig tnrs ig n srsa
                      n tafaynm olyged
                                   eesl
                                    et P
                     ccxicr ga Lrnatn
                      iu tsn o
                     iedne a
                    rn eeoO
                    ga
                    OdEB ri
                     R i    ec     e
                                   Pm
                                    ra
                                Cropland                        Grassland           Peatland

                    Uncertainty: spatial variability, soil and climate types; no human components
Factors limiting carbon sequestration




       Sink saturation

       Non-permanence

       Availability of land and resources

       Adoption of measures / contiguous?
                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?
                                 Feasible Potential in EU-15
                    8
                    7           Cto
                                s rn
                                ea
                                qt
                                 u
                                 esi
                                Ht
                                Gn
                                 r i
                                 e
                                 d
                                Gcuo
Tg C-equ. y-1 in EU-15
                    6
                    5
                    4
                    3
                    2
                    1
                    0
                       t i oc f n e t s t
                       ul einoa gsaro
                      n ig ters ig olnrsa
                      iptafaynm Lrygsin
                           cr ar na R
                     ccxi n i p     e e
                    adEBg c
                    g
                    rR i O
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                     nu ts r
                        eeo         m
                                    r no
                                      e t
                                   Pe
                                Cropland                        Grassland           Peatland

                         Uncertainty: spatial variability, adoption, permanence of adoption
                Environmental effects
                         Tillage Amendments Extensif. Peatland

Herbizides, pestizides               ?

Non-CO2 gases

NH3, NOx                    ?            ?

Biodiversity                    ?

Water quality

Soil quality

Sustainable land
management
                                               Productivity?
                       Farm income
Organic amendments     positive 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?
                 Policy impacts

      Putting C sequestration options into a
     real-world context influenced by policy


Policy effects
 (post 1990)

                     Land use       C sequestration
                      change           potential


Other effects
          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
          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
                  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
               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
     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
    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
     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
            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

								
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