New Zealand Journal of Agricultural Research abstracts
A review of emissions of methane, ammonia, and nitrous oxide from
animal excreta deposition and farm effluent application in grazed
pastures
Surinder Saggar1
N. S. Bolan2
R. Bhandral2
C. B. Hedley1
J. Luo3
1Landcare Research
Private Bag 11 052
Palmerston North, New Zealand
2Department of Soil and Earth Sciences
Institute of Natural Resources
Massey University
Private Bag 11 222
Palmerston North, New Zealand
3Land and Environmental Management
AgResearch Ltd
Ruakura Research Centre
Private Bag 3123
Hamilton, New Zealand
Abstract The agricultural sector in New Zealand is
the major contributor to ammonia (NH3), nitrous oxide (N2O),
and methane (CH4) emissions to the atmosphere. These gases
cause environmental degradation through their effects on soil
acidification, eutrophication, and stratospheric ozone depletion. With
its strong agricultural base and relatively low level of heavy
industrial activity, New Zealand is unique in having a
greenhouse-gas-emissions inventory dominated by the agricultural trace
gases, CH4 and N2O, instead of carbon dioxide
which dominates in most other countries. About 96% of this
anthropogenic CH4 is emitted by ruminant animals as a
by-product during the process of enteric fermentation. Methane is also
produced by anaerobic fermentation of animal manure and many other
organic substrates. In pastoral soils, NH3 and N2O
gases are generated from N originating from dung, urine, biologically
fixed N2, and fertiliser. The amount of these gaseous
emissions depends on complex interactions between soil properties,
climatic factors, and agricultural practices. In this review paper, the
animal-excretal inputs and farm-effluent applications to New Zealand
pastures are quantified. Data from overseas and New Zealand studies on
CH4, NH3, and N2O emissions from
excretal deposition and animal effluents, and the factors affecting
these emissions, are synthesised with an aim to improve the New Zealand
estimates of emissions from these sources. The practical implications
of these emissions are described in relation to environmental impacts
and management strategies for reducing these emissions.
Keywords ammonia; best management practices;
effluent; grazed pasture; manure slurry; methane; nitrous oxide
A04068; ; Online publication date 15 December 2004Received 30 June
2004; accepted 6 September 2004
New Zealand Journal of Agricultural Research, 2004, Vol. 47:
513–544
0028–8233/04/4704–0513 © The Royal Society of New Zealand 2004
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