Greenhouse gas emissions from feed production and enteric fermentation of rations for dairy cows Department of Agroecology, Aarhus University, Denmark: Lisbeth Mogensen, Troels Kristensen, Thu Lan T. Nguyen, Marie T. Knudsen Department of Animal Science, Aarhus University, Dk: Maike Brask, Anne Louise F. Hellwing, Peter Lund, Martin R. Weisbjerg
Outline Carbon footprint (CF) of feed by LCA Growing and processing Transport Land Use Change (LUC) deforestation CF from carbon (C) changes in soil Effect of different feeding strategies CF from feed combined with CH 4 from enteric fermentation
LIFE CYCLE ASSESSMENT Emissions to air (N 2 O, NH 3, CO 2 etc.) INPUT Materials e.g. fertilizer Energy e.g. fuel Chemicals e.g. pesticides Other Barley OUTPUT Crop yield Residues or coproduct Emissions to soil and water (NO 3-, pesticides etc.) transport transport transport Production of inputs Agricultural production Processing Dairy farm
g/co 2 /kg barley 200 180 160 140 120 100 80 60 40 20 0 Carbon footprint of barley - from growing and processing 181 growing (414 g CO 2 ) 132 87 14 9 N2O Fertlizer Energy Seed Processing
Carbon Footprint of feed g/co 2 /kg feed 1400 1200 1000 800 600 400 200 0 Growing Processing
Emission of CO 2 from transport CO 2 -eq, g per tkm Ship 9 Lorry (40 t) 150 Lorry (28 t) 227 Lorry (16 t) 375 Train 40 Plane 1080
Transport of 1 kg product, kg CO 2 eq /kg product By lorry By ship (Knudsen, M.T. 2011)
Transport of feed Feed Land of origin To DK To factory To farm Total CO 2 /kg feed, g Barley Denmark 0 9 6 15 Rapeseed cake Soy bean meal Denmark 47% Germany 53% Argentina 73% Brazil 27% 61 9 34 104 342 0 27 369
Carbon Footprint of feed g/co 2 /kg feed Growing Processing Transport 1400 1200 1000 800 600 400 200 0
World GHG emissions 3,6 16,2 18,2 Land use change (Deforestation) Agriculture 13,5 Transport (energy) 24,6 Indutry (energy) 10,4 13,5 Electricity and heat Waste Other (Baumert et al., 2005. World Resources Institute)
Direct LUC Soy bean meal from Argentina and Brazil Palm oil from Malaysia
Direct LUC Soy bean meal Direct LUC g CO 2 /kg Argentina 930 Brazil 7690 (PAS2050, BSI, 2008)
CF of feed incl. direct LUC g/co 2 /kg feed 3000 Growing Processing Transport Direct LUC 2500 2000 1500 1000 500 0
Method II: Indirect LUC The burden of deforestation caused by food production is shared by all feed production (indirect LUC) As the global demand for food increases, there will be increased pressure on land and thereby land use change somewhere in the world. (Audsley et al., 2009)
Including LUC which method? Direct LUC Indirect LUC 3000 2500 2000 1500 1000 500 0 3000 2500 2000 1500 1000 500 0
Impact of changes in soil carbon C in soil kg CO 2 eq/ha/year Grass sink - 1910 Other crops release + 3080 (Vleeshouwers & Verhagen, 2002)
CF of feed, g CO 2 /kg g/co 2 /kg feed 3500 Growing Processing Transport LUC C in soil 3000 2500 2000 1500 1000 500 0-500 Rape seed cake Wheat Gras pellets Oat Barley Conc. Mix Palm oil Soy bean meal
1. Feed rations based on silage: Grass silage vs. maize silage
Ration Feed intake, kg DM/d: Grass silage Maize silage Wheat 1.6 1.7 Rape seed cake 4.1 4.2 Grass silage 11.0 0 Maize silage 0 11.2 Total 16.6 17.1 Milk production: Kg ECM/day 23.9 24.3 CH 4 : liter/day 516 474 CO 2 -eq, g/kg ECM 385 (114) 337 (100)
GHG from feed, kg CO 2 /kg ECM Growing Processing Transport LUC C in soil Maize ration + 56 % Gras ration -0,1 0 0,1 0,2 0,3 0,4 0,5
GHG from feed + CH 4 from cow, kg CO 2 /kg ECM Growing Processing Transport LUC C in soil CH4 cow Maize ration + 16 % More from feed Due to C in soil Less CH 4 from cow Grass ration -0,2 0 0,2 0,4 0,6 0,8 1
2. Roughage : Concentrate ratio 80 versus 50 % roughage
Ration 80% roughage Feed intake, kg DM/d 50% roughage Wheat 2,0 6,9 Soybean meal 1,8 2,7 Maize silage 5,6 3,4 Grass silage 11,1 6,8 Total 20,4 19,8 Milk production: Kg ECM/d 30,2 30,1 CH 4 : liter/dag 700 617 CO 2 -eq, g/kg ECM 435 (124) 350 (100)
GHG from feed, kg CO 2 /kg ECM Growing Processing Transport LUC C in soil 50% roughage + 45% 80% roughage 0 0,1 0,2 0,3 0,4 0,5 0,6 0,7
GHG from feed + CH 4 from cow, kg CO 2 /kg ECM Growing Processing Transport LUC C in soil CH4 cow 50% roughage + 13% More from feed Less from CH 4 cow 80% roughage 0 0,2 0,4 0,6 0,8 1 1,2
3. Type of protein feed Rapeseed cake versus Soybean meal
Ration- 50% roughage Feed intake, kg DM/d Rapeseed cake Soybean meal Wheat 6.9 6.9 Soybean meal 0 2.7 Rapeseed cake 3.2 0 Maize silage 3.4 3.4 Grass silage 6.8 6.8 Total 19.8 19.8 Milk production: Kg ECM/d 30.1 30.1 CH 4 liter/d 593 617 CO 2 -eq, g/kg ECM 337 (96) 350 (100)
GHG from feed, kg CO 2 /kg ECM Growing Processing Transport LUC C in soil Soyb. Ration + 65% Rapes. Ration 0 0,1 0,2 0,3 0,4 0,5 0,6 0,7
GHG from feed + CH 4 from cow, kg CO 2 eq/kg ECM Growing Processing Transport LUC C in soil CH4 cow Soyb. Ration + 35% More GHG from feed More CH 4 from cow Rapes. Ration 0 0,2 0,4 0,6 0,8 1 1,2
Conclusion Carbon footprint per kg milk (from feed production and enteric CH 4 ) can be reduced by choice of feed: Rapeseed cake in stead of soybean meal (though mainly caused by LUC) Increased Roughage : concentrate ratio? (depend also on type of concentrated feed) Grass-clover silage >< maize silage? (depend on how contribution from C sequestration in soil is included)
Conclusion II Carbon footprint from feed production: Contribution from Land Use Change (LUC) - deforestation and changes in soil C are often hotspots in the calculation Methods needs to be further developed Emissions from produced manure will also be affected by feeding strategy not included Methods and further development needed