mourakohman w2w 2013
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Greenhouse Gas Emissions of Beef Cattle Under Grazing Conditions in Florida
Marta Moura Kohmann- ABE/UF
Dr. Clyde W. Fraisse- ABE/UFDr. Hilary Swain, Archbold Biological StationDr. Martin Ruiz-Moreno, ANS/UFDr. Lynn E. Sollenberger, PhD., AGR/UFDr. Nicolas DiLorenzo, ANS/UFFrancine Messias Ciríaco, ANS/UFDarren D. Henry, ANS/UF
April 2013
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Background
US 2010 Greenhouse Gas Emissions by Economic Sector (percents based on Tg CO2 Eq., left) and in Agriculture (right). Source: EPA, 2012.
33.8
26.9
20.4
7.3
5.65.4
0.7 Electric Power Industry
Transportation
Industry
Agriculture
Commercial
Residential
U.S. TerritoriesTotal (2010): 6.821.8 Tg CO2 Eq.
Agriculture (2010): 494.8 Tg CO2 Eq.
42.0
28.6
14.2
9.61.8 1.7 0.8 0.8 0.2 0.1 0.1 0.1
N2O from Agricultural Soil Management
Enteric Fermentation
Manure Management
CO2 from Fossil Fuel Combustion
CH4 and N2O from Forest Fires
Rice Cultivation
Liming of Agricultural Soils
Urea Fertilization
CO2 and N2O from Managed Peat-lands
Mobile Combustion
N2O from Forest Soils
Field Burning of Agricultural Residues
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Importance• Cattle industry in Florida
– 1.71 million head of cattle
– 940,000 are beef cattle
– 890,000 calves born in 2011
• Typical production systems:
– Cow-calf operations
– low inputs
– pasture based
Source: Florida Department of Agriculture and Costumer Services (2012)
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Objective
The objective is to calculate the carbon footprint of a
typical cow-calf operation in Florida..
Specific objectives are
– Identify main Greenhouse Gas (GHG) sources
– Understand the model used
– Further investigation of ruminal fermentation with field
trials
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Methodology• Buck Island Ranch: on lease from the MacArthur
Foundation to the Archbold Biological Station • Full-scale working ranch– 4,500 acres bahiagrass– 5,640 acres native vegetation– 160 acres citrus
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Methodology
• Cow-calf operation– 3,000 Brahman-cross cows – 150 Angus and Charolais bulls– 2,300 calves annually
• Data: 1998 to 2008• Identify sources of Greenhouse Gas Emissions (GHG)
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MethodologyAnimal GHG sources
• Manure- CH4, N2O• Enteric fermentation
(ruminal)- CH4
Management GHG sources
• Nitrogen fertilization- N2O
• Lime application- CO2
• Burning- CO, CH4, N2O, NOx
• Fossil fuels (molasses transportation, management practices)- CO2
Anatomy of the cow’s digestive tract. Source: University of Minnesota Extension.
• Reticulum, rumen and omasum: anaerobic fermentation
• Hydrolysis and anaerobic oxidation create H+
CO2 + 8H methane + 2H2O
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Methodology
• Intergovernmental Panel on Climate Change (2008)
• EPA (2005)• Results transformed into CO2eq– CH4 = 21 CO2
– N2O = 310 CO2
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Results
GHG source (ton CO2eq) %Enteric Fermentation 6,895.79 58.8Manure Management 2,719.39 23.2
Tractor Operation 188.05 1.6Fertilization 447.63 3.8
Liming 660.80 5.6Pasture Burning 160.70 1.4
Molasses Transport 16.91 0.1Urea for Feeding 393.36 3.4Feed Concentrate 250.77 2.1
Total 11,733.39 100.00
Table 1. Average (t CO2eq) GHG emissions from Buck Island Ranch, data from 1998 to 2008.
82 %
18 %
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1998 1999 2000 2001 2002 2003 2004 2005 2006 2007 20080
2000
4000
6000
8000
10000
12000
0
500
1000
1500
2000
2500
3000
3500
4000
4500
5000
Agrochemicals Total emissions Adult animals
Tota
l em
issio
ns (t
on C
O2e
q/ye
ar)
num
ber o
f ani
mal
s
Results
10,227 t CO2eq
12,954 t CO2eq
Figure 1. Total GHG emissions, emissions from agrochemicals (t CO2eq) and total number of animals in Buck Island Ranch, 1998 to 2008.
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Results
0
10
20
30
40
50
60
70
80
90
100
71
42
29
58
Production, transportation, storage and transfer
After application
Lime Fertilizer (N)
%
Figure 2. GHG emissions from agrochemicals separated by source (t CO2eq)
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Results
• 24.5 kg CO2/ kg live weight that leaves the farm
• 77% of total emissions in cattle production come from the cow-calf operation part
• If animals double weight after they leave the farm
~ 16 kg CO2/ kg final live weightTakashi & Young, 2002
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Ongoing Research
• Field trials in the North Florida Research and Educational Center in Marianna, Florida– Methane measurements using the SF6 technique– Three stocking rates– Animal performance (weight gain)– Pasture measurements (production, nutritive
value)
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Methane emissions measurementSulfur hexafluoride (SF6)
Permeation tube. Source: EPA, 2006.
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Methane emissions measurementSulfur hexafluoride (SF6)
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Methane emissions measurementSulfur hexafluoride (SF6)
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Final considerations
• Methane emissions from ruminal fermentation accounts for 59% of total emissions
• 24.5 kg CO2/ kg live weight that leaves the ranch
• Average 11,733 tons CO2eq/ year• Model still needs further investigation• Field experiments
Future research• In vitro methane measurements• Parametrization
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Acknowledgements
• This study has been funded by the Agriculture and Food Research Initiative Competitive Grant no. 2011-67003-30347 from the USDA-National Institute of Food and Agriculture
Thank [email protected]
Greenhouse Gas Emissions of Beef Cattle Under Grazing Conditions in Florida
Marta Moura KohmannDepartment Agricultural and
Biological Engineering
April 2013