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| Titel |
Ammonia emissions from cattle urine and dung excreted on pasture |
| VerfasserIn |
J. Laubach, A. Taghizadeh-Toosi, S. J. Gibbs, R. R. Sherlock, F. M. Kelliher, S. P. P. Grover |
| Medientyp |
Artikel
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| Sprache |
Englisch
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| ISSN |
1726-4170
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| Digitales Dokument |
URL |
| Erschienen |
In: Biogeosciences ; 10, no. 1 ; Nr. 10, no. 1 (2013-01-23), S.327-338 |
| Datensatznummer |
250017475
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| Publikation (Nr.) |
 copernicus.org/bg-10-327-2013.pdf |
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| Zusammenfassung |
| Twelve cattle were kept for three days in a circular area of 16 m radius on
short pasture and fed with freshly-cut pasture. Ammonia (NH3) emissions
from the urine and dung excreted by the cattle were measured with a
micrometeorological mass-balance method, during the cattle presence and for
10 subsequent days. Daily-integrated emission rates peaked on Day 3 of the
experiment (last day of cattle presence) and declined steadily for five days
thereafter. Urine patches were the dominant sources for these emissions. On
Day 9, a secondary emissions peak occurred, with dung pats likely to be the
main sources. This interpretation is based on simultaneous observations of
the pH evolution in urine patches and dung pats created next to the circular
plot. Feed and dung samples were analysed to estimate the amounts of
nitrogen (N) ingested and excreted. Total N volatilised as NH3 was
19.8 (± 0.9)% of N intake and 22.4 (± 1.3)% of N
excreted. The bimodal shape of the emissions time series allowed to infer
separate estimates for volatilisation from urine and dung, respectively,
with the result that urine accounted for 88.6 (± 2.6)% of the
total NH3 emissions. The emissions from urine represented 25.5 (± 2.0)% of the excreted urine-N, while the emissions from dung amounted to
11.6 (± 2.7)% of the deposited dung-N. Emissions from dung may
have continued after Day 13 but were not resolved by the measurement
technique. A simple resistance model shows that the magnitude of the
emissions from dung is controlled by the resistance of the dung crust. |
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