Potentials for soil carbon sequestration in different livestock feed strategies

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Seminar on Landscapes in a Carbon Focused World 26 October 2012
SIANI, Focali & Naturskyddsföreningen organized a one-day seminar in Gothenburg.

Summary: Grassland for silage, hay and pasture has for long been the traditional roughage feeding strategy for cattle in northern Europe. There is an increasing interest for substituting this with maize silage and more concentrates which probably lead to different soil carbon balances. There are great difficulties to calculate such changes in estimates of GHG emissions from livestock production systems which will be discussed in this section.

Christel Cederberg's research is mainly about environmental impact of livestock production systems in developed countries and focus on GHG emissions and land-use issues. Cederberg has a Master in Agriculture, a PhD in Environmental Science and now works at SIK and is adjunct professor at Chalmers.

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Potentials for soil carbon sequestration in different livestock feed strategies

  1. 1. Potentials for soil carbon sequestrationin different livestock feed strategiesChristel CederbergSIK, the Swedish Institute for Food and BiotechnologyDepartment of Energy and Environment, ChalmersUniversity of TechnologyFocali 26 oct 2012Chalmers University of Technology
  2. 2. Feeding livestock~ 75 % of world agricultural land23%12%65%Arable land,human foodArable land,feed forlivestockPermanentpasture,livestock
  3. 3. Calculating the carbon footprint of milkPrimary production TransportProcessing Packaging Retail & consumerCO2 x 1CH4 x 25N2O x 298CO2 x 1 CO2 x 1 CO2 x 1 CO2 x 100,20,40,60,8Primprod Process Pack Transport Retail&consCO2CH4N2OkgCO2eperkgmilk0.80.60.40.20Prim prod Processing Packaging Transport Retail&cons.CO2CH4N2O
  4. 4. -1000-5000500100015002000MilkMeatAccounting for affected systems – total emissions globally553 Mtonnes milk34 Mtonnes meatDairy sector:GHG emissions (Mtonnes CO2e)associated with the dairy sector290 Mtonnes CO2e ‘saved’~MeatdairysectorMeatcow-calfsystemGerber et al., 2010Gerber et al., 2010
  5. 5. Agricultural GHG emissions 1990-2020(no LULUC)Källa: Smith et al 2007. Agriculture, Ecosystems and Environment 118: 6-28.0100020003000400050006000700080001990 2005 2020 1990 2005 2020 1990 2005 2020Developing countries Developed countries TotalmiljonertonCO2e/årBiomass burning,CH4&N2OManure management,CH4&N2ORice cultivation, CH4Enteric fermentation,CH4Soils, N2O
  6. 6. Global technical mitigation potential by 2030 in globalagricultureSmith et al, 2007 Phil Trans R Soc 363:789-813; IPCC 2007-20002004006008001000120014001600MtonCO2e/yearLustgasMetanKoldioxidClose to 90% of mitigationpotential in 2030 is estimated tobe Soil Carbon Sequestration!
  7. 7. Soil carbon sequestration: Some basicsCarbonstorage,Ton Cper haTIMEArable soilatequilibriumMeasure:conversion fromcropland tograsslandSoil C sequestrationCarbon sinksaturation10 to 100 years…….Carbon sinkpermanence?
  8. 8. Affects soil carbon sequestration• Carbon input– crop residues– organic material (e.g. manure)• Initial carbon stock in soil• Temperature• Clay content• Water content• Carbon/Nitrogen ratio• Tillage(?)
  9. 9. Carbon in harvest products and cropresidues-8-6-4-20246C inharvestC in cropresiduesTonC/ha
  10. 10. Important limitations for soil carbonsequestration as a GHG mitigation option• Carbon sink saturation – soils reach C saturationafter 20-50(100) yrs• Achieved C sequestration is reversible – the sameland use must go on ”forever” to avoid C loss• Displacement effects – e.g. if peatlands are takenout of production to reduce GHG emissions,foregone food production must take placeelsewhere, maybe by ploughing grasslands(releasing carbon) or on deforested land• Monitoring – verification that a particularmeasure has increased soil carbon stock is costly
  11. 11. • C sequestration potentials in feed production
  12. 12. Energy from grainProteinpulsesProteinCo-productsfrom oilcropsSyntetiska aminosyror för snabbtillväxtEnmagade djur – generellt om deras foderFeeding monogastric animals
  13. 13. Cropland management for increasedC sequestration• Agronomy practices >higher yields >more cropresidues (e.g. extending crop rotations with perennialcrops) ~0.88 t CO2/ha*yr• Improved nutrient management ~0.55 tCO2/ha*yr• Minimal – no tillage ~0.5 t CO2/ha*yr• Agroforestry ~0.5 t CO2/ha*yr• Land cover change, cropland to nativevegetation/grassland ~3 t CO2/ha*yrSmith et al, 2007 Phil Trans R Soc 363:789-813; IPCC 2007
  14. 14. Idisslare – generellt om deras foderEnergy and proteins fromgrasslandEnergy fromgrains Proteinfromoil seedcropsFeeding ruminants
  15. 15. Observed effects on C-seq ingrassland soilsNet C seq (+) oremission (-)t CO2e/ha yrReferensVariable C stock change, several studies +13 till -6 Soussana m fl (2010)Predicted range, C stock change,European grasslands+6 till -2a Janssens m fl (2005)Conversion cropland to pasture +3,7 Conant m fl (2001)Conversion cropland to grass +1,8 Soussana m fl (2004)Conversion more leguminous plants +1,1 till +1,8 Soussana m fl (2004)Conversion from short to permanentgrasslands+1,1 till +1,5 Soussana m fl (2004)Increased duration ley/grassland +0,7 till +1,8 Soussana m fl (2004)Improved pasture management +1,3 Conant m fl (2001)Fertilisation +1,1b Conant m fl (2001)Reduction of N-input +1,1c Soussana m fl (2004)Higherplantdiversity in grasslands +15 till +2,1 Steinbeiss m fl (2008)Management of grasslands for CsequestrationCederberg m fl 2012. Jordbrukets potential som kolsänka, SIK-report in publication
  16. 16. Milk and beef can be produced with differentfeed rations…..effects on soil carbon changes?0,000,100,200,300,400,500,600,700,80Baseline Maize & grass More&BetterGrasskgDMfeedperkgmilkConcentratesGrainSuper-pressed pulpMaize silageGrass/clover silage, pastureProduction level9000 kgmilk/cow*yearWirsenius & Cederberg, ”Soil carbon sequestration as a greenhouse gas mitigation option in dairyproduction”, manus in prep
  17. 17. Experiences from modelling soil C changes fordifferent feed rations in milk production• Initial soil carbon status is very important forthe soil´s carbon sequestration potential• The estimated soil carbon changes aresignificant, but not of great importance formilk´s total GHG balance• Feed rations with more maize silage seem toloose soil carbon• Reasonably correct data on crop residues fromgrasslands are needed – big lack of data!
  18. 18. Landscape focus with a carbon approach• Develop knowledge andunderstanding oncarbon fluxes and stocks• System analysis, goingfrom product and farmlevel to landscape level -up-scaling?... Interactioneffects?…….• Risk for displacementeffects?
  19. 19. Thank you!

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