Publication Date:
2006-05-01
Description:
Carbon dioxide, methane and nitrous oxide emissions from agricultural sources have a significant role in the overall enhancement of the global greenhouse gas (GHG) effect. In research, measurements of GHG emissions are made to improve upon emission factors used in national inventories, identify and promote mitigation practices, and drive policy on GHG emissions in agriculture. These measurements are fundamental to the process of better management of GHG emissions. There is a variety of measurement techniques used in GHG research depending on the measurement environment and available resources. Techniques that use chambers or micrometeorological measurements are commonly employed for calculating emissions of GHG from point sources in agriculture, such as livestock and manure-holding facilities. This review examines these techniques, their limitations, and discusses methods to quantify their accuracy and precision. Emerging techniques like the use of dispersion models provide opportunities to directly determine emissions from whole farms. A few micrometeorological techniques (integrated horizontal flux and mass difference) are ideal for point sources such as manure storage facilities. For smaller sources, chambers are still recommended. In designing GHG emission studies, employing more than one technique when measuring GHG emissions is recommended, as often differences can exist due to technique. Ideally, a controlled release of the target gas, and its recovery, should also be conducted to evaluate techniques prior to their application. Although many techniques are often sensitive enough to quantify mitigation practices, i.e., the relative change in emissions, it is more difficult to determine “ true”emission factors as required for inventory work. It follows that the precision and accuracy of the techniques must accompany their application when estimating GHG emissions. Key words: Greenhouse gas, techniques, chambers, methane, agriculture, cattle
Print ISSN:
0008-4271
Electronic ISSN:
1918-1841
Topics:
Geosciences
,
Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
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