Abstract
area of 16m radius on short pasture and fed with freshlycut
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.
Original language | English |
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Pages (from-to) | 327 - 338 |
Number of pages | 12 |
Journal | Biogeosciences |
Volume | 10 |
Issue number | 1 |
DOIs | |
Publication status | Published - 2013 |
Externally published | Yes |