Emissions from Western Dairy Production


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Proceedings available at: http://www.extension.org/67622

Concentrated dairy operations emit trace gases such as ammonia (NH3), methane (CH4), and nitrous oxide (N2O) to the atmosphere. The implementation of air quality regulations in livestock-producing states increases the need for accurate on-farm determination of emission rates. Our objective was to compare the emission rates of NH3, CH4, and N2O from three commercial dairies in southern Idaho that vary in size, animal housing, and manure handling systems. The three dairies consisted of a small open lot dairy (700 cows), large open lot dairy (10,000 cows) and a large open-freestall dairy (10,000 cows) with an anaerobic digester. Both housing and manure management systems were monitored in order to determine "whole farm emissions" and determine the effects of manure handling practices on emissions from the different farm sectors. Gas concentrations and wind statistics were measured and used with an inverse dispersion model to calculate emission rates. Average emissions from the housing area per cow per day for the three farms ranged from 0.10 -- 0.14 kg NH3, 0.33-0.49 kg CH4 and 0.01 - 0.02 kg N2O. Average emissions from the wastewater ponds (g cow-1 d-1) were 10 - 129 NH3, 27 -- 1,028 CH4 and 3.7 -- 4.9 N2O. Data from this study can be used to develop trace gas emissions factors from dairies in southern Idaho and other production systems in similar climatic regions.

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Emissions from Western Dairy Production

  1. 1. Emissions from Dairy ProductionSystems in a Semi-Arid ClimateA. B. Leytem, R. S. Dungan and D. L. BjornebergUSDA-ARS, NWISRL, Kimberly, ID
  2. 2. Milk Production by State0510152025CA WI ID NY%TotalMilkProduction2012 Milk ProductionCA + ID 28%
  3. 3. 2010 Dairy Cattle Populations2010 Populations9.1 million milk cows + heifers that had calved4.5 million replacement heifersSemi-arid to Arid Climate≤ 270 mm average annual rainfall
  4. 4. Dairy Cattle HousingHousing in the western U.S. is uniquewith 30% of lactating cattle housedin dry lots, which represents most ofthe dry lot housing in the countryDry LotFreestallOpen-freestall
  5. 5. Impacts of NH3 emissions• Formation of PM2.5 particulate matterwhich is a human health concern• Dry/wet deposition of N leading to overfertilization and loss of species diversityor water quality impairmentEmissions from LivestockEstimates of US ammonia emissionsfrom Livestock (EPA, 2004)Dairy23%Beef27%Poultry28%Swine18%Ammonia (NH3) Emissions> 70% of total U.S.ammonia emissions isfrom livestock sectorAgricultural sources of GHG Emissions(USDA, 2005)EntericFermentation22%Grazed Lands22%Manure Mgt.10%Cropland Soils35%EnergyUse35%Greenhouse Gas (GHG) EmissionsCH4 GWP = 21N2O GWP = 310Methane (CH4) and Nitrous Oxide (N2O)• Concern from a climate changeperspectiveEnteric + Manure emissions(CH4 + N2O) was 3.3% of totalCO2e emissions in the U.S.
  6. 6. Objective: Measure Ammonia andGreenhouse Gas Emissions fromDry-lot and Open freestallDairies in Southern Idaho
  7. 7. Prevailing Wind DirectionFarm 1. 700 Milking CowProduction Facility (780 totalcows with ~60 m2 cow-1)Farm 2. 10,000Milking CowProduction Facility(10,800 total cowswith ~55m2 cow-1)Farm 3. 10,000 Milking CowProduction Facility (10,000total cows with ~27m2 cow-1)
  8. 8. Ammonia and Methane EmissionsOver TimeNH3kgday-101000200030004000TimeTue 29 0:00:00 Wed 30 0:00:00CH4kgday-105000100001500020000250003000024 h window
  9. 9. Summer Fall Winter AverageDL (700) DL (10,000) FS (10,000)Ammonia Emissions From HousingNH3Emissions(kgHead-1d-1)• Emissions from dry-lots tend to be the lowest in winter whensoils are frozen and covered with snow and temperatures are low• Emissions from dry-lots tend to be the highest when you havemoist lot conditions with higher wind speeds• Emissions from freestall barns are more related to temperatureand ventilation
  10. 10. MarchAugustJulyJuneMayAprilSeptemberFebruaryJanuaryDecemberNovemberOctoberSpatial distribution ofammonia on large drylot dairyManure RemovedSoil Replaced
  11. 11. Comparison of Average Ammonia EmissionsFrom Housing with NAEMS DataNH3Emissions(kgHead-1d-1) ID2 ID3 CA IN NY TX WA WI
  12. 12. Summer Fall Winter AverageDL (700) DL (10,000) FS (10,000)Methane Emissions From HousingCH4Emissions(kgHead-1d-1)• Emissions tend to be higher in spring on dry lot dairies• Emissions similar between dry-lots and freestall barn17-21 g CH4 kg-1 DMI
  13. 13. Summer Fall Winter AverageDL (700) DL (10,000) FS (10,000)Nitrous Oxide Emissions From HousingN2OEmissions(kgHead-1d-1)• Emissions are low and quite variable
  14. 14. 020406080100120140160Spring Summer Fall Winter AverageDL (700) DL (10,000) FS (10,000)Ammonia Emissions from WastewaterPondNH3Emissions(kgha-1d-1)• Emissions tend to be lower during colder months• The freestall dairy had much higher emissions than the dry lotdairies
  15. 15. 050010001500200025003000Spring Summer Fall Winter AverageDL (700) DL (10,000) FS (10,000)Methane Emissions From WastewaterPondCH4Emissions(kgha-1d-1)• Emissions tend to be lower during colder months• The freestall dairy on average had lower emissions than the largedry lot dairy but greater than the small dry lot dairy.• As the manure went through anaerobic digestion prior to theponds we would expect the methane to be less than untreatedwaters
  16. 16. 05101520Spring Summer Fall Winter AverageDL (700) DL (10,000) FS (10,000)Nitrous Oxide Emissions FromWastewater PondN2OEmissions(kgha-1d-1)• Emissions tend to be variable and low
  17. 17. r² = 0.92R² = 0.9604080120160200240-10 0 10 20 30 40AmmoniaEmissions(kg/ha/d)Temperature ( C)FS (10,000)DL (700)r² = 0.79R² = 0.960200400600800-10 0 10 20 30 40MethaneEmissions(kg/ha/d)Temperature ( C)Relationship Between WastewaterEmissions and Temperature
  18. 18. 0100200300400MarchAprilMayJuneAugustSeptemberAverageAmmonia Methane Nitrous OxideEmissions From Compost Yard on DryLot DairyEmissions(kgha-1d-1)• The greatest emissions were methane• Turning of the compost windrows (June) showed the greatestimpact on emission rates“
  19. 19. Contribution of Different ProductionSectors on Emissions at Dry Lot DairyAmmoniaLots WW Pond Compost78%Methane SpringLots WW Pond Compost74%Methane SummerLots WW Pond Compost55%Nitrous OxideLots WW Pond Compost57%
  20. 20. 020406080100120Spring Summer Fall Winter Spring Summer Fall WinterOpen-Freestall Wastewater PondsAmmonia MethaneContribution of Different ProductionSectors on Emissions at OFS Dairy%
  21. 21. Total Farm Emissions on 10,000 CowDairiesDry Lot Open-FreestallNH3 CH4 NH3 CH4------------------------ kg d-1 ----------------------Spring (Mar-May) 1,699 14,495 2,656 9,502Summer (June- Aug.) 1,581 13,080 3,318 9,443Fall (Sept.-Nov.) 1,748 26,834 1,809 7,917Winter (Dec.-Feb.) 1,474 5,760 273 3,215Average Total Emissions, kg d-1 1,625 15,042 2,014 7,519Average emission cow-1 d-1 0.15 1.39 0.20 0.75Average emission kg milk-1 d-1 0.005 0.044 0.006 0.022
  22. 22. N Intake676 g/dMilk N165 g/dNH3 emissions150-200 g/dNitrogen BalanceUrine N277 g/dFecal N199 g/dBased on a calculated N balance:22-30% of total N ingested was lost as NH332-42% of total N excreted was lost as NH354-72% of urinary N excreted was lost as NH3Literaturevalues reportranges of 3-52%
  23. 23. On Farm Values vs. Modeled EstimatesFrom Animal HousingOn-FarmValueDairyGEMkg cow-1 d-1700 Cow DL NH3 0.16 0.17CH4 0.33 0.31N2O NA 0.0110,000 Cow DL NH3 0.13 0.15CH4 0.49 0.43N2O 0.01 0.0110,000 Cow FS NH3 0.08 0.07CH4 0.43 0.44N2O 0.03 0.01Can be used to test BMP effects on emissions
  24. 24. Questions?