The contribution of cattle urine and dung to nitrous oxide emissions: Quantification of country specific emission factors and implications for national inventories
Date
2018-04-24
Journal Title
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Publisher
Elsevier
Abstract
Urine patches and dung pats from grazing livestock create hotspots for production and emission of the greenhouse
gas, nitrous oxide (N2O), and represent a large proportion of total N2O emissions in many national agricultural
greenhouse gas inventories. As such, there is much interest in developing country specific N2O emission
factors (EFs) for excretal nitrogen (EF3, pasture, range and paddock) deposited during gazing. The aims of this
study were to generate separate N2O emissions data for cattle derived urine and dung, to provide an evidence
base for the generation of a country specific EF for the UK from this nitrogen source. The experiments were
also designed to determine the effects of site and timing of application on emissions, and the efficacy of the nitrification
inhibitor, dicyandiamide (DCD) on N2O losses. This co-ordinated set of 15 plot-scale, year-long field experiments
using static chambers was conducted at five grassland sites, typical of the soil and climatic zones of
grazed grassland in the UK. We show that the average urine and dung N2O EFs were 0.69% and 0.19%, respectively,
resulting in a combined excretal N2O EF (EF3), of 0.49%, which is b25% of the IPCC default EF3 for excretal
returns from grazing cattle. Regression analysis suggests that urineN2O EFs were controlledmore by composition
than was the case for dung, whilst dung N2O EFs were more related to soil and environmental factors. The urine
N2O EF was significantly greater from the site in SW England, and significantly greater from the early grazing season urine application than later applications. Dycandiamide reduced the N2O EF fromurine patches by an average
of 46%. The significantly lower excretal EF3 than the IPCC default has implications for the UK's national inventory
and for subsequent carbon footprinting of UK ruminant livestock products
Description
Publication history: Accepted - 10 April 2018; Published online - 24 April 2018.
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Article
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Keywords
Grassland, Greenhouse gas, Nitrous oxide, Cattle, Urine patch, Dung pat, Nitrification inhibitor
Citation
Chadwick, D. R., Cardenas, L. M., Dhanoa, M. S., Donovan, N., Misselbrook, T., Williams, J. R., Thorman, R. E., McGeough, K. L., Watson, C. J., Bell, M., Anthony, S. G. and Rees, R. M. (2018) ‘The contribution of cattle urine and dung to nitrous oxide emissions: Quantification of country specific emission factors and implications for national inventories’, Science of The Total Environment, 635, pp. 607–617. doi: 10.1016/j.scitotenv.2018.04.152.