Greenhouse Gas Emissions from U.S. Livestock Production
Systems
D. Johnson, H. Phetteplace, A. Seidl
Colorado State University
Outline, AN448,Sept. 22, 2004
I. Global greenhouse gas accumII. Agriculture and livestock role
III. Livestock system sources IV. Manure system GHG’s
V. Mitigation strategies
References: Agric GHG’s
IPCC, 2001 (06): GHG Inventory Good Practice Guidelines (ipcc-nggip.iges.or.jp)USEPA, 2004: Inventory of US GHG (yosemite.epa.gov/oar/globalwarming)USDA, 2004: US Agric. & Forestry GHG (usda.gov/oce/gcpo) Proc. Agstar Conf. Anaerobic Digestion (epa.gov/agstar/conference04)
SOURCE: IPCC
SOURCE: Science, 1-11-2002
Global Climate Changes (IPCC)
Snow cover: 10% decreaseGlacier retreat: majorRiver and lake ice: 2 wk decreaseSea ice extent: 10-15% decreaseArctic ice thickness: 40% decreaseDiurnal temp range: decreaseTropospheric water, clouds: increase
SOURCE: IPCC
SOURCE: IPCC
GHG Sources in US (as CO2 equivalent)
CO2
CH4 x 21N2O x 310
5004
649389
5782
598 416
0
1000
2000
3000
4000
5000
6000
1990 2002
CO2CH4N2O
Importance of Non-CO2 GHG’s
Why bother?Globally – 40%Effective fast Cost effectivePolitical feasibilitySynergy-other problems
Climate Forcings of GHG’s, CO2eq in US, 2002, %
CH49%
CO283%
HFC, PFC, SF62%
N2O6%
Agriculture’s Role, cont’d
70% of Nitrous oxide30% of Methane
Huge C-sequestration potential
Agriculture sources of GHG (USDA, 04)
0
510
15
2025
30
3540
4550
Crop-N2O StorSht-N2O Enteric-CH4 Manure-CH4
%
Global N-input Sources (Mosier and Kroeze, 99)
Products and GHG from Cattle Production
JW
Herd
100 cows+ others
Cropping
Feeds
Manure
CH 4 N20FuelC02
Soil Carbon
(+)
Beef System GHGs
CO2eq by Gas Source (100 cow US system)Gas t/yr CVCH4 221 4N2O 308 10CO2 66 17Cseq -53
18Total: 542 7 -100
-50
0
50
100
150
200
250
300
350
CH4 N2O CO2 Cseq
GHG Sources by Beef Sector(CO2, N2O, CH4 as CO2eq)
0
2
4
6
8
10
12
14
16
18
20
Cow Calf Stocker Feedlot Cow-Feedlot
Production Phase
CO
2 E
quiv
alen
ts p
er g
ain
(kg)
CO2
N2O
Total CH4
Dairy System GHGs (100 cow herd, t/yr)
Gas CalifWiscCH4, enteric 320 292
CH4, manure 185 18
N2O 331 298
CO2 254 274
C-sequest 0 (28)Total 1090 854
Waste GHG, Beef Cattle
Waste, Dairy Cattle
Waste, Swine
Biological N transformations(Nitrification-Denitrification)
NH4 NH3
NO2-
N2O
NO3-
NO2-
NON2ON2
N2O
Nitrification
Denitrification
Aerobic
Anaerobic
Manure handling systemsVariations in N2O-N per Manure N
3.95.751.22.0Aerobic
2.75.752.00Graze
2.05.751.20.1Slurry
1.95.751.20Daily spread
SumLeach
DisposalStorageSystem-------------------N20/N, %-------------------
-
Manure methane equations
Livestock characterization and pop.Waste characteristicsWaste management system usageMethane conversion factor (MCF)
EPA, 2002, 04
Manure methane emissions
Kg CH4/yr by state for each animal group
CH4 an grp = Σ(pop. x VS x Bo x MCF x 0.662)
pop = avg head animal group for each stateVS = VS in kg/head/yearBo = max CH4 prod capacity/kg VSMCF = weighted MCF for animal group by state0.662 = conversion factor of m3 CH4 to kg CH4
EPA, 2002
SpeciesTotal
Kjeld. N, kg/d
VS, kg/dMax. CH4
Bo, m3 CH4/kg VS
Dairy cow 0.44 9.30* 0.24
Dairy heifer 0.31 7.77 0.17
Feedlot cattle 0.30 5.44 0.33
Beef cow 0.33 6.20 0.17
Market swine* 0.42 5.40 0.48
Breeding swine 0.24 2.60 0.48
Hens 0.83 10.8 0.39
Broilers 1.10 15.0 0.36
From Table L-2, EPA, 2002, *CO #s
US-EPA Manure GHG inventory assumptions, 2002 (N &VS/1000 kg animal mass)
Methane Conversion Factor
Based on Van’t Hoff-Arrhenius equation
f = exp[E(T2 –T1)/RT1T2]
f = portion of VS available for CH4 production
T1 = 303.16 K
T2 = weighted ambient temp (K) for each state
E = activation energy (15,175 cal/mol)R = ideal gas constant (1.987 cal/K mol)
EPA, 2002; Safley & Westerman, 1990
Manure methane in 2002
EPA, 2004
0
5
10
15
20
Dairy Beef Swine Poultry Other
CO
2eq,
Tg
Total 40 Tg CO2 eq
Manure N2O, CO2eq (USDA 04) Total = 77 Tg/yr
0
10
20
30
40
50
60
Dairy Beef Swine Poultry other
N2O, t/yr
All Mitigation Approaches Must:
be based on a comprehensive, life cycle analysis that assesses emissions of all greenhouse gases.
(NCCTI, 2001)
CH4 Mitigation (Mgt strategies)
Eliminate anaerobic lagoons or capture CH4
Eliminate stocker phase ~ direct to feedlot
Maximize grain feeding – trade-offs with N2O
Dilution of maintenance Faster gain or more milk/cow Hormone treatment use bST or implants
Biogas from Livestock Waste
Prior failures: 140 farm sys in 70’s (< 20%)Renewed interest: 50 now in use, 60 planCost $400 - $1200/cow, brk even 5 – 15c/kWhGHG savings: 6 MT/cow?Synergisms? Odor, NH3- PM2.5, dust, health, acid rain, smog, etc.
US Biogas Plants, USDA 04
Methane Mitigation Research
Immunization (Baker, Aust)Methane oxidizers (UK)H+ acceptors Nitrate (Japan) Fumaric acid (UK, Japan)Medium chain Fatty Acids (Switz)
CH4 Mitigation (Mgt strategies cont.)
Select cows with low maintenance req. Increase forage digestibility
• Intensive Grazing• Plant genetic select/modification• ? Fat cows if fed ad libitum• Tradeoff excess N (>20%CP, req~11%) • Ammoniation of forage – trade-off with N2O
MCFA – trade-off enteric, manure
Diet %CP, Manure Sys vs N2O(Kulling,et. 01 J Ag Sci 137:235)
Lactating Cows, 30.9 kg/d, 3 protein levels, +bypass Methionine 12.5 15 17.5%
3 Manure management systems Liquid manure in slurry (Slurry) Farmyard manure, liquid urine (FYM-US) Deep liter + 12 kg straw (DLM-Straw)
Dairy % diet CP vs Emissions(Kulling 01, J Ag Sci 137:235)
0
10
20
30
40
50
60
70
80
NH3-N N2O,mg/10 CH4,g GWP/10
17.5
15
12.5
Manure System vs Emissions(Kulling 01)
0
10
20
30
40
50
60
70
80
90
NH3 N2O CH4 GWP
Slurry
FYM-U
DLM-Strw
Manure vs. Synthetic N
250 kg N-Manure Stores 350 kg
C Fuel (0) N2O-C 655 kg
Net emissions 305 kg CE(1100 kg CO2eq)
250 kg N-Synthetic Stores 150 kg C Fuel 296 kg C N2O-C 655 kg
Net emissions 801 kg CE(2900 CO2eq)
80
- 51
- 118
Direct-IG
95
- 58
- 41
Direct
14.2GHG/BW sold, % base
0$ /T GHG
529Net GHG , T/herd
1997 Base
Abatement Strategies on Beef GHG Emissions & Profit
Conclusions
Manure Mgt? Anaerobic; N2O, CH4 Covered lagoons?
Efficient manure use
Need good emission estimates
Conclusions
GHG abatement strategies should consider emissions of all GHG’sReductions in feed/product central thrustDilution of maintenanceReductions in excess N Soil C can add modest offsets to livestock