Greenhouse gas emissions from dairy housing/stand-off pad systems in New Zealand
A number of improved off-paddock livestock facilities (eonfinernents) are increasingly being used by New Zealand dairy farmers: feed pads, stand-off pads, animal shelters or housing; largely to avoid pasture and soil treading damage and for ease of herd management during wet winter periods.This review assesses the impacts on greenhouse gas (GHG) emissions of farming systems that include the use of animal confinements.Feed pads and/or stand-off pads are widely used on farms throughout New Zealand (~50% of dairy farms), while the use of animal shelters or wintering houses typically used for extended periods of time on farms is still very low (~2% of dairy farms).When confined animals void their urine and dung on stand-off/feed pads or in houses, various types of slurry and solid manures are produced.These are generally stored for some time before subsequent application to land.There are wide variations in animal manure/slurry storage and mamagement systems that include differences in manure collection methods, amendments with litter or other materials, storage periods and the method and timing of land application.Each step in the management of these manures/slurries has its own set of physical and environmental conditions which affect GHG (methane, nitrous oxide and ammonia) production and emissions.Greenhouse Gas losses from both animal confinement and pasture-based systems mainly occur as methane emission from enteric fermentation.Wintering-offof dairy cattle can potentially decrease enteric methane emissions by changing or balancing diets and saving energy that would otherwise be needed for grazing and locomotion outside.Other hotspots in the confinement systems are methane and nitrous oxide emissions from manure/slurry storage and management and GHG emissions associated with the production of food concentrates (e.g., grains).A preliminary system analysis using a life cycle assessment (LCA) methodology indicated that the use of stand-offpads or housing for wintering dahy cows (that would otherwise be grazed on pasture) can lead to an increase in the carbon footprint of milk produced from dairy farm systems (by up to 7%), where there are no other farm system changes.This is due in part to the increase in GHG emissions as a result of management of manure/slurry collected from the pad or housing systems.However, results were highly dependent on the methane and nitrous oxide emission factors used for the analysis.We need to quantify GHG emissions from each component of the off-paddock systems by conducting field measurements of methane and nitrous oxide emissions, so that accurate data can be incorporated into thetotal GHG footprint analysis.
J.Luo C.Pinares H.Wang B.Longhurst D.Houlbrooke S Ledgard T.van der Weerden B.Woodward S.Saggar S.Lau renson C.deKkin
AgResearch,Ruakura,Private Bag 3123,Hamilton 3240,New Zealand AgResearch,Grasslands,Private Bag 11008,Palmerston North 4442,New Zealand A & F University,Linan,Hangzhou,311300,P.R.China AgResearch,Invermay,Private Bag 50034,Mosgiel 9053,New Landcare Research,Private Bag 11052,Palmerston North 4442,New Zealand
国际会议
浙江嘉兴
英文
219-224
2013-10-24（万方平台首次上网日期，不代表论文的发表时间）