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Effect of exposed surface area on ammonia emissions from untreated, separated, and digested cattle manure

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Ammonia (NH 3) emissions from land-applied liquid manure (slurry) contribute to nitrogen deposition, acidification, and formation of fine particles in the atmosphere. Optimal management and field application techniques can reduce emission. A reduction in contact area between the slurry and the atmosphere is expected to reduce NH 3 emission. The objectives of this study were to develop a method for quantifying the exposed surface area (ESA) of field-applied slurry over time, and determine the degree to which ESA explains differences in NH 3 emission. Two experiments were conducted in which untreated, separated, and digested slurry was applied in bands on two different soils with spring oats stubble. Emission data were obtained from online wind tunnel measurements and slurry characteristics such as surface pH, viscosity, and particle size distribution were measured. The new ESA method relies on fluorescent dye added to the slurry prior to field application, followed by imaging. The results show that the ESA measurements can give new insight into the soil-slurry interactions after manure application, and this may help explain why some types of slurry and application techniques lead to successful abatement under some circumstances, but not under others. Furthermore, a pH-, TAN-, temperature-, and ESA-normalised NH 3 emission were estimated, helping idetify the effects of infiltration.

Original languageEnglish
JournalBiosystems Engineering
Pages (from-to)66-78
Number of pages13
Publication statusPublished - Feb 2021

    Research areas

  • Ammonia volatilisation, Band application, Manure surface pH, Normalised emission, Wind tunnels

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