Nitrous oxide and the NZ ETS
Prof. Tim Clough
New Zealand’s specialist land-based university
IPCC AR4
New Zealand’s specialist land-based university
Comparison of annual N2O ODP-weighted emissions from the 1990s [IPCC, 2007 (18, 23)] with
emissions of other ozone-depleting substances in 1987, when the emissions of chlorine- and
bromine-containing ODSs were near their highest amount, and for 2008. (Ravishankara et al.
2009, Science)
N2 O → N 2 + O
N2O + O → 2NO
NO + O3 → NO2 + O2
O + NO2 → NO + O2
net: O + O3 → 2O2
New Zealand’s specialist land-based university
Between 1860 to 2005 Davidson
(2009) suggests that roughly 2.0%
of annual manure-N production
and 2.5% of fertilizer-N
production have been converted
to N2O…these percentage
contributions explain the entire
pattern of increasing nitrous
oxide concentrations over this
period
Nature Geoscience 2, 659 - 662 (2009)
New Zealand’s specialist land-based university
Wrage et al. 2001 Soil Biol. & Biochem.
Nitrification
New Zealand’s specialist land-based university
Wrage et al. 2001 Soil Biol. & Biochem.
Nitrifier-Denitrification
New Zealand’s specialist land-based university
Need to reduce agriculture’s impact on climate
change

Greenhouse gas (GHG)
emissions:
 Agriculture accounts for
50% of NZ’s total GHG.
 Nitrous oxide (N2O) has a
global warming potential
298 times greater than
CO2 over a 100 year
period.
New Zealand’s specialist land-based university
Nitrous oxide emissions from Agricultural soils
Greenhouse
gas emissions
as a percentage of New Zealand's
total Agricultural
Greenhouse gas emissions in 2003
from NZ agriculture
Nitrous
Nitrous oxide oxide
(34.9% )
34%
Methane 64%
(10%>1990)
Methane (63.4% )
(27% > 1990
levels)
Other (1.7% )
In grazed pastures urine patches are the main sources of nitrous
oxide emissions and nitrate leaching
1,000 kg N/ha in urine patch ( = 2 t Urea/ha)
New Zealand’s specialist land-based university
Urea fertiliser only applied at 30 kg N/ha
What can we do about N2O?
New Zealand’s specialist land-based university
Covered feed & loafing pad
(Cecile De Klein, AgResearch)
New Zealand’s specialist land-based university
•
•
•
•
Low-nitrogen pasture plants
A major new research programme is among
the first to be funded by the New Zealand
Agricultural Greenhouse Gas Research Centre.
Led by Dr Susanne Rasmussen, it focuses on
the feasibility of growing high-yielding pasture
species with a lower nitrogen content.
If results prove that growing the species will
be viable, this would open up the possibility of
farmers being able to maintain pasture
productivity while reducing the amount of
nitrogen excreted.
The outcome would be multiple
environmental benefits, for example a
reduction in greenhouse gas emissions. Lownitrogen plants would also address the
problem of nitrogen leaching into waterways,
helping to improve water quality
New Zealand’s specialist land-based university
Nitrification rate is related to Ammonia
Oxidising Bacteria (AOB) population
(Di et al., 2009. Nature Geoscience: 2: 621-624 )
(a)
NO 3--N (mg N kg -1 soil)
1000
800
600
y = 847.9 - 739.6EXP(-0.018x)
R 2 = 0.56; P < 0.001
400
200
Fitted curve
Observed values
0
0
20
40
60
80
100
120
AOB amoA gene copy numbers (million copies g-1 soil)
New Zealand’s specialist land-based university
140
Nitrification inhibitor temporarily blocks
the active site of a specific enzyme
(ammonia monooxygenase)
inhibitor
New Zealand’s specialist land-based university
Nitrification inhibitors can reduce nitrous oxide emissions
and nitrate leaching
N 2O
NH4+
---Cation exchange
Nitrification inhibitor
slows down the rate of
nitrate production and
thus reduces the
nitrogen
New Zealand’s
specialistlosses
land-based university
NO3-
Nitrification inhibitor thus restricts ammonia oxidising
bacteria (AOB) population growth in soil
(Di et al., 2009. Nature Geoscience: 2: 621-624 )
(a)
Copy numbers g -1 soil
5.0E+07
Control
Urine
Urine + DCD
4.0E+07
3.0E+07
2.0E+07
1.0E+07
0.0E+00
0
20
40
60
Days since start of treatments
New Zealand’s specialist land-based university
80
100
AOB activity data show response to urine and
inhibition by DCD nitrification inhibitor
RNA copy numbers
µg-1 RNA
(Di et al., 2009. Nature Geoscience: 2: 621-624 )
5.0E+04
4.0E+04
3.0E+04
2.0E+04
1.0E+04
0.0E+00
Control
Urine
Urine +
DCD
Control
AOB
AOA
Treatments
New Zealand’s specialist land-based university
Urine
Urine +
DCD
Nitrification inhibitor reduces the nitrate
concentration in soil
(Di et al., 2009. Nature Geoscience: 2: 621-624 )
(c)
NO 3--N (mg kg -1 soil)
1200
Control
Urine
Urine + DCD
1000
800
600
400
200
0
0
20
40
60
Days since start of treatments
New Zealand’s specialist land-based university
80
100
Inhibitor is applied in April/May and July
because most leaching occurs in the winter/early spring
CHRISTCHURCH: Mean Soil Temperature (at 10cm) and
Estimated Drainage (mm)
50
20
Estimated Drainage (mm)
inhibitor
18
inhibitor
16
35
14
30
12
25
10
20
8
15
6
10
4
5
2
0
0
0
40
Jan
Feb
Mar
Apr
May
Jun
Jul
Aug
Sep
Oct
Nov
Dec
Months
New Zealand’s specialist land-based university
Soil Temperature
45
Drainage (mm)
Soil Temp (C)
Nitrous oxide gas emissions from gas chambers placed on
lysimeters for a standard 40 minutes each day.
New Zealand’s specialist land-based university
DCD reduced N2O emissions by 81% in the
Waikato
Horotiu soil (Di et al., 2010)
1600
Urine
Urine + Eco-N
Control
Daily N2O flux (g N2O-N ha-1 d-1)
1400
1200
1000
800
600
400
200
0
3/05/06
23/05/06
New Zealand’s specialist land-based university
12/06/06
Sampling date
2/07/06
22/07/06
Soil
Location of
soil
irrigation
(mm/y)
DCD
EF3
(%)
in EF3 (%)
Di & Cameron
(2002)
Spring
Lismore
Canterbury
1,360
No
3.8
-
Soil Use &
Management
18, 395-403.
Lismore
Canterbury
1,360
Yes
0.7
82
Lismore
Canterbury
850
No
2.2
-
Autumn
Autumn
Autumn
Spring
Spring
Spring
Spring
Lismore
Lismore
Lismore
Lismore
Lismore
Lismore
Lismore
Canterbury
Canterbury
Canterbury
Canterbury
Canterbury
Canterbury
Canterbury
850
850
850
850
850
850
850
Yes
Yes
Yes
No
Yes
Yes
Yes
0.6
0.6
0.4
1.5
0.4
0.4
0.2
73
73
82
73
73
87
Di & Cameron
(2006)
Autumn
Lismore
Canterbury
1,050
No
1.9
-
Autumn
Autumn
Spring
Spring
Autumn
Autumn
Autumn
Lismore
Lismore
Lismore
Lismore
Lismore
Templeton
Templeton
Templeton
Canterbury
Canterbury
Canterbury
Canterbury
Canterbury
Canterbury
Canterbury
Canterbury
1,050
1,050
1,050
1,050
1,050
1,050
1,050
1,050
Yes
Yes
Yes
No
Yes
No
Yes
Yes
0.7
0.6
0.5
2.6
0.7
3.1
1.2
1.4
65
70
73
73
61
56
Winter
Templeton
Canterbury
1100
No
2
Winter
Autumn
Autumn
Autumn
Autumn
Spring
Spring
Templeton
Lismore
Lismore
Horotiu
Horotiu
Taupo
Taupo
Canterbury
Canterbury
Canterbury
Waikato
Waikato
Taupo
Taupo
1100
1100
1100
1100
1100
1100
1100
Yes
No
Yes
No
Yes
No
Yes
0.5
0.8
0.3
0.6
0.2
0.1
0.02
Lismore
Lismore
Mataura
Mataura
Harihari
Harihari
Lismore
Lismore
Mataura
Mataura
Harihari
Harihari
Canterbury
Canterbury
Southland
Southland
West Coast
West Coast
Canterbury
Canterbury
Southland
Southland
West Coast
West Coast
1100
1100
1100
1100
1100
1100
2200
2200
2200
2200
2200
2200
No
Yes
No
Yes
No
Yes
No
Yes
No
Yes
No
Yes
3
1.4
2
0.9
1.9
0.8
3.9
1
1.5
1
1.4
0.4
Reference
Season
Spring
Di & Cameron
(2003)
Autumn
Soil Use &
Management
19, 284-290
Biology &
Fertility of Soils
42, 472-480.
Autumn
Di et al.
(2007)
Soil Use &
Management
23, 1-9.
Di et al.
(2009) in press Autumn
Autumn
Autumn
Autumn
Autumn
Autumn
Autumn
Autumn
Autumn
Autumn
Autumn
Autumn
73
63
67
80
54
55
58
74
33
71
New
university
Average
EF3Zealand’s
reductionspecialist
(%) for all land-based
trials
68%
(s.e. = 2.5)
57% ( 3.1)
•A consolidated table of all NZ published data on N2O reductions by
DCD (de Klein et al. 2011) .
•Data from over 45 New Zealand trials under a wide range of soil,
environment and management conditions.
•The average N2O reduction with DCD was 57% ( 3.1).
“The United Nations Framework Convention on
Climate Change (UNFCCC) Expert Review Team
commended New Zealand for incorporating the
effect of the nitrification inhibitor, dicyandiamide
(DCD), into its country-specific emissions factors, as
DCD represents a potentially significant mitigation
option that may gain increased use over time”
http://www.maf.govt.nz/news-resources/news/more-accurate-science-improvesagriculture%E2%80%99s-green
New Zealand’s specialist land-based university
Nitrate leaching losses
New Zealand’s specialist land-based university
Soil lysimeter facilities in different regions
Waikato: Horotiu soil
New Zealand’s specialist land-based university
Canterbury: Templeton and Lismore
Taupo pumice soil
DCD reduced nitrate leaching from a
Canterbury Lismore soil (Di et al., 2009)
NO3--N concentration (mg L-1)
300
Urine
Urine + DCD
250
200
150
100
50
0
0
50
100
150
200
Cumulative drainage (mm)
New Zealand’s specialist land-based university
250
300
350
NO3--N leaching loss (kg ha-1)
Nitrate leaching losses reduced in a range of South
Island soils (Di et al. 2009)
56%
600
67%
71%
44%
56%
Urine only
500
Urine plus eco-n (May +
Aug)
400
300
200
100
0
Urine
Urine +
DCD
Canterbury
Urine
Urine +
DCD
Southland
Urine
Urine +
DCD
West Coast
1100 mm rainfall
New Zealand’s specialist land-based university
Urine
Urine +
DCD
Southland
Urine
Urine +
DCD
West Coast
2200 mm rainfall
Treatments
Nitrate leaching losses reduced in North Island Soils
Data from Shepherd et al. 2009 (AgResearch).
FLRC Conference Proceedings.
700
Urine only
NO3- - N leaching loss (kg ha-1)
31%
35%
55%
600
33%
Urine plus eco-n (May +
Aug)
500
400
300
200
100
0
urine
urine+DCD
urine
Waikato
urine+DCD
Northland
1100mm rainfall
New Zealand’s specialist land-based university
urine
urine+DCD
Waikato
urine
urine+DCD
Northland
2200mm rainfall
Treatments
AgResearch study showed DCD reduced nitrate leaching
lost by between 21 and 56%, depending on the year of
study (P < 0.05)
New Zealand’s specialist land-based university
(Monaghan et al. 2009. NZJ Agricultural Research 52; 145-159)
FertResearch Fact Sheet #11
“Nitrification Inhibitors”
Paddock scale reduction in nitrate leaching
PER HECTARE PER YEAR
10-30%
25-40%
North Island
South Island
http://www.fertresearch.co.nz/code-of-practice/factsheets
New Zealand’s specialist land-based university
DCD degradation and soil temperature
160
NZ data
Half life, days
120
80
40
International literature (4 studies)
0
0
10
20
Temperature, deg C
Kelliher & Clough et al. Soil Biol. Biochem. 2008
New Zealand’s specialist land-based university
30
Inhibitor effects on other soil microbes?
AgResearch study concluded that:
• “DCD had little impact on the overall soil bacterial activity.
• In contrast the microbes targeted by DCD, the ammoniumoxidising bacteria, were significantly affected by DCD with
reductions in population size and altered activity.
• The results suggest that application of DCD to pasture is a
relatively benign intervention that has an important role to
play in mitigating the environmental hazards imposed by
ongoing land use intensification.”
New Zealand’s specialist land-based university
Pasture Production
New Zealand’s specialist land-based university
Retaining more nitrogen in the soil can produce more pasture
growth
Lincoln University
Lincoln University
Control plot: no ‘eco-n’
‘eco-n’ plot
New Zealand’s specialist land-based university
National Trial Series shows significant increases in pasture
growth from dicyandiamide.
(132 data sets from 37 large on-farm grazed pasture trials)
Increase in DM response (%)
30%
25%
20%
15%
10%
5%
0%
North Island
South Island
NZ overall
Carey et al. (2011).
New Zealand’s specialist land-based university
Thank you
New Zealand’s specialist land-based university
Calculating DCD emission factors (EF)
EF1 ' plusDCD '  ( IPCC default EF1)  ( IPCC default EF1 
50% 5 months

)  0.0099
100% 12 months
kg N2O/kg fertiliser-N
EF 3PRP ' plus DCD  n'  ( IPCC default EF 3PRP)  ( IPCC default EF 3PRP 
50% 5 months

)  0.0079
100% 12 months
kg N2O/kg excreta-N
(Clough etspecialist
al. 2007 land-based
Nutr. Cycl. Agroecosyst.
New Zealand’s
university 78:1-14. )
Table 8
Module
Submodule
Worksheet
Sheet
Pasture, range and paddock
AWMS
PRP nil DCD
PRP plus DCD
2003 Agriculture (New Zealand)
Agricultural soils
4.5 (3 of 5)
Direct nitrous oxide emissions from animal production (grazing
animals)
N excretion
Emission
Total direct
Total direct
for AWMS
factor for
animal prodn.
animal
PRP
AWMS (EF3
emissions
prodn.
(kg N)
of N2O-N (Gg)
emissions
PRP)
(kg N2O-N/kg
of N2O (Gg)
N)
1,386,897,313
143,375,290
#Assumes 25% of dairy cattle under eco-n regime
New Zealand’s specialist land-based university
0.0100
0.0079
13.869
0.836
21.794
1.314
Effect of eco-n on N2O inventory
nil eco-n
N2 O emissions relative to 1990 (%)
eco-n 5 month effective period
eco-n 5 month effective period but weighted emissions of 84%
130
128
126
124
122
120
118
116
114
0
10
New Zealand’s specialist land-based university
20
30
40
50
60
% dairy cattle under eco-n regime
70
80
New Zealand’s specialist land-based university