Potentials for soil carbon sequestration in different livestock feed strategies

Christel Cederberg SIK, the Swedish Institute for Food and Biotechnology

Department of Energy and Environment, Chalmers University of Technology

Focali 26 oct 2012

Chalmers University of Technology

Feeding livestock ~ 75 % of world agricultural land

23%

12% 65%

Arable land,human food

Arable land,feed forlivestock

Permanentpasture,livestock

Calculating the carbon footprint of milk

Primary production Transport Processing Packaging Retail & consumer

CO2 x 1 CH4 x 25 N2O x 298

CO2 x 1 CO2 x 1 CO2 x 1 CO2 x 1

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CO2

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kg C

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ilk

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Prim prod Processing Packaging Transport Retail&cons.

CO2

CH4

N2O

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-500

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Milk

Meat

Accounting for affected systems – total emissions globally

553 Mtonnes milk

34 Mtonnes meat

Dairy sector:

GHG emissions (Mtonnes CO2e) associated with the dairy sector

290 Mtonnes CO2e ‘saved’ ~

Meat dairy sector

Meat cow-calf system

Gerber et al., 2010

Gerber et al., 2010

Agricultural GHG emissions 1990-2020 (no LULUC)

Källa: Smith et al 2007. Agriculture, Ecosystems and Environment 118: 6-28.

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1990 2005 2020 1990 2005 2020 1990 2005 2020

Developing countries Developed countries Total

milj

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CO

2e

/år

Biomass burning,CH4&N2O

Manure management,CH4&N2O

Rice cultivation, CH4

Enteric fermentation,CH4

Soils, N2O

Global technical mitigation potential by 2030 in global agriculture

Smith et al, 2007 Phil Trans R Soc 363:789-813; IPCC 2007

-200

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Lustgas

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Koldioxid

Close to 90% of mitigation potential in 2030 is estimated to

be Soil Carbon Sequestration!

Soil carbon sequestration: Some basics

Carbon storage, Ton C per ha

TIME

Arable soil at equilibrium

Measure: conversion from cropland to grassland

Soil C sequestration

Carbon sink saturation

10 to 100 years…….

Carbon sink permanence

?

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(?)

Carbon in harvest products and crop residues

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-6

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C in harvest

C in crop residues

Ton C/ha

Important limitations for soil carbon sequestration as a GHG mitigation option

• Carbon sink saturation – soils reach C saturation after 20-50(100) yrs

• Achieved C sequestration is reversible – the same land use must go on ”forever” to avoid C loss

• Displacement effects – e.g. if peatlands are taken out of production to reduce GHG emissions, foregone food production must take place elsewhere, maybe by ploughing grasslands (releasing carbon) or on deforested land

• Monitoring – verification that a particular measure has increased soil carbon stock is costly

• C sequestration potentials in feed production

Energy from grain Protein

pulses

Protein

Co-products from oil crops

Syntetiska aminosyror för snabb tillväxt

Enmagade djur – generellt om deras foder Feeding monogastric animals

Cropland management for increased C sequestration

• Agronomy practices >higher yields >more crop residues (e.g. extending crop rotations with perennial

crops) ~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 native vegetation/grassland ~3 t CO2/ha*yr

Smith et al, 2007 Phil Trans R Soc 363:789-813; IPCC 2007

Idisslare – generellt om deras foder

Energy and proteins from grassland

Energy from grains Protein

from oil seed crops

Feeding ruminants

Observed effects on C-seq in grassland soils

Net C seq (+) or emission (-)

t CO2e/ha yr

Referens

Variable 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 permanent grasslands

+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 C sequestration

Cederberg m fl 2012. Jordbrukets potential som kolsänka, SIK-report in publication

Milk and beef can be produced with different feed rations…..effects on soil carbon changes?

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Baseline Maize & grass More&BetterGrass

kg D

M f

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d p

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kg m

ilk

Concentrates

Grain

Super-pressed pulp

Maize silage

Grass/clover silage, pasture

Production level 9000 kg milk/cow*year

Wirsenius & Cederberg, ”Soil carbon sequestration as a greenhouse gas mitigation option in dairy production”, manus in prep

Experiences from modelling soil C changes for different feed rations in milk production

• Initial soil carbon status is very important for the soil´s carbon sequestration potential

• The estimated soil carbon changes are significant, but not of great importance for milk´s total GHG balance

• Feed rations with more maize silage seem to loose soil carbon

• Reasonably correct data on crop residues from grasslands are needed – big lack of data!

Landscape focus with a carbon approach

• Develop knowledge and understanding on carbon fluxes and stocks

• System analysis, going from product and farm level to landscape level - up-scaling?... Interaction effects?…….

• Risk for displacement effects?

Thank you!