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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 accum. II. Agriculture and livestock role. III. Livestock system sources. IV. Manure system GHG’s.
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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 accum II. 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)
Global Climate Changes (IPCC) • Snow cover: 10% decrease • Glacier retreat: major • River and lake ice: 2 wk decrease • Sea ice extent: 10-15% decrease • Arctic ice thickness: 40% decrease • Diurnal temp range: decrease • Tropospheric water, clouds: increase
GHG Sources in US (as CO2 equivalent) • CO2 • CH4 x 21 • N2O x 310
Importance of Non-CO2 GHG’s Climate Forcings of GHG’s, CO2eq in US, 2002, % Why bother? • Globally – 40% • Effective fast • Cost effective • Political feasibility • Synergy-other problems
Agriculture’s Role, cont’d • 70% of Nitrous oxide • 30% of Methane • Huge C-sequestration potential
Global N-input Sources (Mosier and Kroeze, 99)
J W Products and GHG from Cattle Production Herd Cropping Feeds 100 cows + others Manure ( ) + Soil Fuel CH N 0 Carbon 2 4 C0 2
Beef System GHGs CO2eq by Gas Source (100 cow US system) Gas t/yr CV CH4 221 4 N2O 308 10 CO2 66 17 Cseq -53 18 Total: 542 7
Dairy System GHGs (100 cow herd, t/yr) Gas Calif Wisc CH4, enteric 320 292 CH4, manure 185 18 N2O 331 298 CO2 254 274 C-sequest 0 (28) Total 1090 854
Biological N transformations(Nitrification-Denitrification) N2O NH4 NH3 NO2- Aerobic NO3- Nitrification N2O NO2- NO N2O N2 Denitrification Anaerobic
Manure methane equations • Livestock characterization and pop. • Waste characteristics • Waste management system usage • Methane 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 state VS = VS in kg/head/year Bo = max CH4 prod capacity/kg VS MCF = weighted MCF for animal group by state 0.662 = conversion factor of m3 CH4 to kg CH4 EPA, 2002
US-EPA Manure GHG inventory assumptions, 2002 (N &VS/1000 kg animal mass) From Table L-2, EPA, 2002, *CO #s
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 Total 40 Tg CO2 eq EPA, 2004
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 plan • Cost $400 - $1200/cow, brk even 5 – 15c/kWh • GHG savings: 6 MT/cow • ?Synergisms? Odor, NH3- PM2.5, dust, health, acid rain, smog, etc.
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)
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) Manure vs. Synthetic N
1997 Base Direct Direct-IG Net GHG , T/herd 529 - 41 - 118 GHG/BW sold, % base 14.2 95 80 $ /T GHG 0 - 58 - 51 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’s • Reductions in feed/product central thrust • Dilution of maintenance • Reductions in excess N • Soil C can add modest offsets to livestock