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