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)
SOURCE: IPCC
SOURCE: Science, 1-11-2002
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
SOURCE: IPCC
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SOURCE: IPCC
GHG Sources in US (as CO 2 equivalent) 6000 5782 CO 2 CH 4 x 21 N 2 O x 310 5000 4000 3000 2000 5004 CO2 CH4 N2O 1000 649 389 598 416 0 1990 2002
Importance of Non-CO 2 GHG s Why bother? Globally 40% Effective fast Cost effective Political feasibility Synergy-other problems Climate Forcings of GHG s, CO2eq in US, 2002, % CH4 9% N2O 6% HFC, PFC, SF6 2% CO2 83%
Agriculture s Role, cont d 70% of Nitrous oxide 30% of Methane Huge C-sequestration potential
Agriculture sources of GHG (USDA, 04) 50 45 40 35 30 25 20 15 10 5 0 Crop-N2O StorSht-N2O Enteric-CH4 Manure-CH4 %
Global N-input Sources (Mosier and Kroeze, 99) 200 150 N-Input (Tg N) 100 50 0 1800 1900 1930 1950 1960 1970 1980 1990 1996 Year Synthetic N N-Fixation Crop Residue Animal Manure
Products and GHG from Cattle Production Herd 100 cows + others Feeds Cropping Manure ( + ) CH 4 N 2 0 Fuel C0 2 Soil Carbon J W
Beef System GHGs CO 2 eq by Gas Source (100 cow US system) 350 300 250 Gas t/yr CV 200 CH 4 221 4 150 N 2 O 308 10 100 50 CO 2 66 17 0 Cseq -53 18-50 Total: 542 7-100 CH4 N2O CO2 Cseq
GHG Sources by Beef Sector (CO 2, N 2 O, CH 4 as CO 2 eq) CO2 Equivalents per gain (kg) 20 18 16 14 12 10 8 6 4 2 0 CO2 N2O Total CH4 Cow Calf Stocker Feedlot Cow-Feedlot Production Phase
Dairy System GHGs (100 cow herd, t/yr) Gas Calif Wisc CH 4, enteric 320 292 CH 4, manure 185 18 N 2 O 331 298 CO 2 254 274 C-sequest 0 (28) Total 1090 854
Waste GHG, Beef Cattle
Waste, Dairy Cattle
Waste, Swine
Biological N transformations (Nitrification-Denitrification) N 2 O NH 4 NH 3 NO2 - Aerobic Nitrification NO 3 - N 2 N 2 O N 2 O Anaerobic NO Denitrification NO 2 -
Manure handling systems Variations in N 2 O-N per Manure N System Daily spread Slurry Storage Disposal 0 1.2 Leac h Sum -------------------N 2 0/N, %------------------- -.75 1.95 0.1 1.2.75 2.05 Graze 0 2.0.75 2.75 Aerobic 2.0 1.2.75 3.95
Manure methane equations Livestock characterization and pop. Waste characteristics Waste management system usage Methane conversion factor (MCF) EPA, 2002, 04
Manure methane emissions Kg CH 4 /yr by state for each animal group CH 4 an grp = Σ(pop. x VS x B o x MCF x 0.662) pop = avg head animal group for each state VS = VS in kg/head/year B o = max CH 4 prod capacity/kg VS MCF = weighted MCF for animal group by state 0.662 = conversion factor of m 3 CH 4 to kg CH 4 EPA, 2002
US-EPA Manure GHG inventory assumptions, 2002 (N &VS/1000 kg animal mass) Species Total Kjeld. N, kg/d VS, kg/d Dairy cow 0.44 9.30* Max. CH 4 Bo, m 3 CH 4 /kg VS 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
Methane Conversion Factor Based on Van t Hoff-Arrhenius equation f = exp[e(t 2 T 1 )/RT 1 T 2 ] f = portion of VS available for CH 4 production T 1 = 303.16 K T 2 = 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 CO2eq, Tg 20 15 10 5 0 Total 40 Tg CO 2 eq Dairy Beef Swine Poultry Other EPA, 2004
Manure N2O, CO2eq (USDA 04) Total = 77 Tg/yr 60 50 40 30 20 N2O, t/yr 10 0 Dairy Beef Swine Poultry other
All Mitigation Approaches Must: be based on a comprehensive, life cycle analysis that assesses emissions of all greenhouse gases. (NCCTI, 2001)
CH 4 Mitigation (Mgt strategies) Eliminate anaerobic lagoons or capture CH 4 Eliminate stocker phase ~ direct to feedlot Maximize grain feeding trade-offs with N 2 O 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.
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)
CH 4 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 N 2 O MCFA trade-off enteric, manure
Diet %CP, Manure Sys vs N 2 O (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) 80 70 60 50 40 30 20 17.5 15 12.5 10 0 NH3-N N2O,mg/10 CH4,g GWP/10
Manure System vs Emissions (Kulling 01) 90 80 70 60 50 40 30 20 10 0 NH3 N2O CH4 GWP Slurry FYM-U DLM-Strw
Manure vs. Synthetic N 250 kg N-Manure Stores 350 kg C Fuel (0) N 2 O-C 655 kg Net emissions 305 kg CE (1100 kg CO 2 eq) 250 kg N-Synthetic Stores 150 kg C Fuel 296 kg C N 2 O-C 655 kg Net emissions 801 kg CE (2900 CO 2 eq)
Abatement Strategies on Beef GHG Emissions & Profit 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
Conclusions Manure Mgt? Anaerobic; N 2 O, CH 4 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