A Fonterra Guide to Climate Change

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What factors cause animal emissions to fluctuate?Research from the Pastoral Greenhouse Gas Research Consortium indicates that there is a correlation between thegenetics of the animal and the emissions it releases. Research into this link is ongoing.Another factor is feed consumption: the more food consumed, the higher the emissions. If highly productive animalscan be identified, this will result in more milk being produced from fewer cows. This will lower the amount ofmaintenance feed required and, ultimately, reduce emissions from the herd.What is the status of research into the use of nitrification inhibitors?Nitrification inhibitors can increase productivity while lowering nitrous oxide emissions. Trials have shown 30-70 percent reductions in nitrous oxide production through the use of inhibitors and they also have been shown to improvepasture productivity by between 15-20 per cent under the best conditions. However there are some questionsremaining around their effectiveness in different soil types and conditions.Fonterra is working with the Ministry of Agriculture and Forestry, DairyNZ, the Pastoral Greenhouse Gas ResearchConsortium and the fertiliser industry to undertake further research which will provide further clarification of theregional variation in results.Nitrification inhibitors must gain formal international recognition before they can be counted as a tool for reducingNew Zealand’s agricultural emissions. The process of gaining international recognition is currently underway, and ifsuccessful nitrification inhibitors will be the first approved mitigation technique for agricultural emissions.Fonterra has said that improving animal productivity can reduce methaneemissions for a set volume of milk. How does this work?Research has suggested that improving productivity will result in fewer emissions for a set volume of milk production(also referred to as lower emissions intensity).Methane emissions arise from the feed consumed by the animal for normal body maintenance, growth or milk production.So the more feed consumed the greater the quantity of methane emitted. Producing the same volume of milk with feweranimals means that less feed is needed for body maintenance, but the same amount of feed is needed for milk production.Therefore less feed in total is required to produce the same volume of milk, resulting in lower methane emissions.Increase productivity per animalDDMI Milk yield (kg/d) CH 4 (kg/d) % CH 4 associated with CH 4 /milk (g/kg)MaintenanceProduction7.9 12 206 51 49 17.210.5 20 272 39 61 13.611.7 24 305 34 66 12.7Source: O’Hare et al. (2003)If the dairy system is carbon in (pasture) and carbon out (milk), shouldn’tit be carbon neutral?Carbon is absorbed into the pasture from atmospheric carbon dioxide with approximately 75 per cent released backinto the atmosphere from plant respiration and decomposition. The remaining carbon in plant material is consumed bythe animal and provides the energy needed for its maintenance and milk production. The carbon in faeces, urine andmilk products is also eventually released back to the atmosphere as carbon dioxide. However, a small portion of thecarbon in pasture is released not as carbon dioxide (CO2), but as methane (CH4) which arises when feed is digested.Under the Kyoto protocol methane is considered to have 21 times the heat trapping ability of carbon dioxide over a100 year period. Therefore the carbon balance of the dairy farm system may be neutral but the problem is that thedairy cow changes a small proportion of carbon into something that has a greater impact on the atmosphere – leavingthe total dairy system in the red.There is some debate regarding the current treatment of methane under the Kyoto Protocol, including the differentatmospheric lifetimes of different gases and the comparability of warming at different times in the future fromdifferent gases. Fonterra is encouraging the New Zealand Government to ensure the science is clarified andappropriately reflected in any future international rules.14
sources of methane (Ch 4 ) in grazing ruminantsCh 4Ch 4Ch 4typically 5-8% of energy in food is lost as enteric methane.What about the carbon stored in my soil?Soils store large amounts of carbon. However, since the Kyoto Protocol compares everything back to a base year(1990), the issue for New Zealand is whether the amount of carbon stored under pastoral soils is higher or lower thanthe base year. If we have increases in soil carbon, then we are effectively removing it from the atmosphere and we willget credit for it. But if soil carbon declines, we are effectively releasing it back into the atmosphere and will thereforeincur a liability.There is a lot of uncertainty in this country as to whether pastoral soils are gaining or losing carbon. We’re workingunder the assumption that pastoral soils are not doing either and have opted not to account for carbon changes undersoil as part of our Kyoto commitment.So New Zealand won’t gain any credit for increases in pastoral soil carbon, but we also won’t incur liabilities associatedwith decreases. Research is continuing to improve our understanding of soil carbon dynamics, which includesinvestigating the potential for a new product, bio-char, to boost the quantity of carbon stored in pastoral soils.Why doesn’t the carbon absorbed by pasture plants on dairy farms countas part of the farm emissions balance?Plants absorb carbon dioxide from the atmosphere during photosynthesis, capturing carbon and energy in plantmaterial. However, half the carbon absorbed is released back into the atmosphere through plant respiration. A furtherquarter of the carbon absorbed is released back to the atmosphere via the decomposition of plant and root material.And the remainder is contained in leaves eaten by the cow. So rather than being stored in the pasture, carbon is cycledaround from the atmosphere, into the plant, and back to the atmosphere in a continuous process.The following table illustrates the working of carbon fluxes, the movement of carbon in and out of the atmosphereand carbon sinks (reservoirs that take in and store more carbon than they release).15
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Page 6 and 7: What is the New Zealand Government
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A Fonterra Guide to Climate Change

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