Download Nitrous oxide emissions and relationships with ammonia oxidisers

Nitrous oxide emissions
and relationships with ammonia oxidisers, soil conditions,
and application of a nitrification inhibitor
Professor Hong J DiA
Keith CameronA, Andriy PodolyanA, Bruce BallB and Jizheng HeC
A
Lincoln University, New Zealand
B Scottish Rural University College, Scotland
C Chinese Academy of Sciences
New Zealand research is a
collaborative partnership
funded by
Sources of nitrous oxide in New Zealand
• Nearly half (48.4%) of all NZ’s
greenhouse gas emissions in
2013 came from agriculture.
• NZ’s GHG reduction target:
11% below 1990 by 2030.
• Agricultural N2O emissions in
2013 were 23% higher than
1990.
Nitrous oxide emissions from Agricultural soils
Greenhouse
gas
as a percentage of
New emissions
Zealand's total Agricultural
gas emissions in 2003
from NZ Greenhouse
agriculture
(2013)
Nitrous
oxide 22%
Nitrous oxide
(34.9% )
Other (1.7% )
Other
Methane 73%
Methane (63.4% )
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collaborative partnership
funded by
Sources of direct and
indirect N2O emissions
in grazed pastures:
N2O
emissions
 Urine
patches are the
main sources of both
direct and indirect N2O
emissions.
losses from N
fertilisers are relatively
small.
700 kg N/ha
 Direct
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collaborative partnership
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NO3-
N2O emissions in winter forage grazing
• Extremely high stocking density
• High number of urine patches
• Soils are wet, favouring NO3leaching and N2O emissions
• Trampling and soil compaction
• How do soil moisture and animal
trampling affect N2O emissions?
• How effective are nitrification
inhibitors?
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collaborative partnership
funded by
Can N2O emissions be reduced by inhibiting ammonia oxidisers
under these conditions?
DCD
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collaborative partnership
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Research conducted
• A series of experiments conducted to determine:
• Effect of soil moisture content on ammonia oxidisers (AOB,
AOA) and N2O emissions;
• Effect of animal trampling on AOB and AOA and N2O emissions;
• Effect of nitrification inhibitor on AOB and AOA and N2O
emissions.
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collaborative partnership
funded by
Methods include laboratory incubation, field plots and lysimeters
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Ammonia oxidizing bacteria (AOB) grew rapidly after urine
application at 130% FC and was inhibited by DCD
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Di et al., 2014
Copyright © 2010 New Zealand Agricultural Greenhouse Gas Research Centre
15 FEBRUARY 2016 |
8
Ammonia oxidizing bacteria (AOB) at 60% FC did not grow
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collaborative partnership
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Copyright © 2010 New Zealand Agricultural Greenhouse Gas Research Centre
15 FEBRUARY 2016 |
9
AOA grew in the Control at 130% FC;
Urine-N inhibited AOA growth at 130% FC.
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AOA amoA gene abundance
copies g-1 dry soil
Dry soil conditions inhibited AOA growth
9.0E+07
60% Control
8.0E+07
60% Urine
7.0E+07
60% Urine + DCD
6.0E+07
5.0E+07
4.0E+07
3.0E+07
2.0E+07
1.0E+07
0.0E+00
0
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collaborative partnership
funded by
50
100
150
Days since treatment application
200
250
N2O emissions were strongly influenced by soil moisture status
• Emissions at 130% FC were 45 times higher than at 100% FC, and
400 times higher than at 60% FC;
• DCD was highly effective in reducing N2O emissions under wet
conditions
Di et al., 2014
New Zealand research is a
collaborative partnership
funded by
Copyright © 2010 New Zealand Agricultural Greenhouse Gas Research Centre
12
A field study showed that animal trampling reduced
air permeability
(Ball et al., 2012)
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collaborative partnership
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15 FEBRUARY 2016 |
13
Copyright © 2010 New Zealand Agricultural Greenhouse Gas Research Centre
Animal trampling increased N2O emissions;
DCD was highly effective in reducing N2O emissions
New Zealand research is a
collaborative partnership
funded by
15 FEBRUARY 2016 |
14
Copyright © 2010 New Zealand Agricultural Greenhouse Gas Research Centre
Nitrous oxide emissions are related to AOB abundance
a
N2O flux (kg N2O-N ha-1)
50
y = 23.4 - 24.3EXP(-0.031x)
2
R = 0.47; P < 0.01
40
Measured
Modelled
30
20
10
0
0
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collaborative partnership
funded by
20
40
60
80
100
120
-1
AOB amoA gene copy numbers (million copies g soil)
140
N2O emissions not related to AOA population abundance
b
N2O flux (kg N2O-N ha-1)
50
40
30
20
10
0
0
2
4
6
8
10
AOA amoA gene copy numbers (million copies g-1 soil)
New Zealand research is a
collaborative partnership
funded by
12
14
Summary
• Soil moisture content has a major influence on AOB
and AOA growth; as well as on N2O emissions.
• Animal trampling can significantly increase N2O
emissions.
• In the high N urine patch soil, AOB play the dominant
role in ammonia oxidation.
• N2O emissions are related to AOB growth not AOA.
• DCD is highly effective in inhibiting ammonia oxidisers
and mitigate N2O emissions under wet and trampled
soil conditions.
New Zealand research is a
collaborative partnership
funded by
Acknowledgements
New Zealand funding provided through the NZAGRC-PGgRc science programme. Research is carried out under
contract between the researcher’s home organisation, the NZAGRC and the PGgRc.
New Zealand funding provided by the New Zealand Government to support the objectives of the Livestock
Research Group of the Global Research Alliance on Agricultural Greenhouse Gases. Any view or opinion expressed
does not necessarily represent the view of the Global Research Alliance on agricultural greenhouse gases.
New Zealand funding provided by the New Zealand Government through the Sustainable Land Management and
Climate Change (SLMACC) research programme. Any view or opinion expressed does not necessarily represent the
view of the New Zealand Government.
New Zealand research is a
collaborative partnership
funded by