new zealand’s specialist land-based university nitrous oxide and the nz ets prof. tim clough

New Zealand’s specialist land-based university

Nitrous oxide and the NZ ETS

Prof. Tim Clough


IPCC AR4


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)

N2O → N2 + O

N2O + O → 2NO

NO + O3 → NO2 + O2

O + NO2 → NO + O2

net: O + O3 → 2O2


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)


NitrificationWrage et al. 2001 Soil Biol. & Biochem.


Nitrifier-DenitrificationWrage et al. 2001 Soil Biol. & Biochem.


Need to reduce agriculture’s impact on climate changeGreenhouse 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.

Nitrous oxide emissions from Agricultural soilsas a percentage of New Zealand's total Agricultural

Greenhouse gas emissions in 2003

Methane (63.4%)

Other (1.7%)

Nitrous oxide(34.9%)

Greenhouse gas emissions from NZ agriculture

Nitrous oxide 34%

(27% > 1990 levels)

Methane 64% (10%>1990)


1,000 kg N/ha in urine patch ( = 2 t Urea/ha) Urea fertiliser only applied at 30 kg N/ha

In grazed pastures urine patches are the main sources of nitrous oxide emissions and nitrate leaching


What can we do about N2O?


Covered feed & loafing pad

(Cecile De Klein, AgResearch)


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. Low-nitrogen plants would also address the problem of nitrogen leaching into waterways, helping to improve water quality


Nitrification rate is related to Ammonia Oxidising Bacteria (AOB) population(Di et al., 2009. Nature Geoscience: 2: 621-624 )

0

200

400

600

800

1000

0 20 40 60 80 100 120 140

AOB amoA gene copy numbers (million copies g-1 soil)

NO

3- -N

(m

g N

kg

-1 s

oil

)

Fitted curveObserved values

y = 847.9 - 739.6EXP(-0.018x)

R 2 = 0.56; P < 0.001

(a)


Nitrification inhibitor temporarily blocks the active site of a specific enzyme (ammonia monooxygenase)

inhibitor


NH4+

- - - -

NO3-

Cation exchange

Nitrification inhibitor slows down the rate of nitrate production and thus reduces the nitrogen losses

Nitrification inhibitors can reduce nitrous oxide emissions and nitrate leaching

N2O


Nitrification inhibitor thus restricts ammonia oxidising bacteria (AOB) population growth in soil (Di et al., 2009. Nature Geoscience: 2: 621-624 )

(a)

0.0E+00

1.0E+07

2.0E+07

3.0E+07

4.0E+07

5.0E+07

0 20 40 60 80 100

Days since start of treatments

Co

py

nu

mb

ers

g-1

so

il

ControlUrineUrine + DCD


AOB activity data show response to urine and inhibition by DCD nitrification inhibitor(Di et al., 2009. Nature Geoscience: 2: 621-624 )

0.0E+00

1.0E+04

2.0E+04

3.0E+04

4.0E+04

5.0E+04

Control Urine Urine +DCD

Control Urine Urine +DCD

Treatments

RN

A c

op

y n

um

ber

s

µg

-1 R

NA

AOB AOA


Nitrification inhibitor reduces the nitrate concentration in soil(Di et al., 2009. Nature Geoscience: 2: 621-624 )

(c)

0

200

400

600

800

1000

1200

0 20 40 60 80 100

Days since start of treatments

NO

3- -N

(m

g k

g-1

so

il)

ControlUrineUrine + DCD


Inhibitor is applied in April/May and Julybecause most leaching occurs in the winter/early spring

CHRISTCHURCH: Mean Soil Temperature (at 10cm) and Estimated Drainage (mm)

0

5

10

15

20

25

30

35

40

45

50

Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov DecMonths

Est

imat

ed D

rain

age

(mm

)

0

2

4

6

8

10

12

14

16

18

20

Soi

l Tem

pera

ture

0

Drainage (mm)

Soil Temp (C)

inhibitor inhibitor


Nitrous oxide gas emissions from gas chambers placed on lysimeters for a standard 40 minutes each day.


DCD reduced N2O emissions by 81% in the Waikato Horotiu soil (Di et al., 2010)

0

200

400

600

800

1000

1200

1400

1600

3/05/06 23/05/06 12/06/06 2/07/06 22/07/06Sampling date

Da

ily N

2O f

lux

(g

N2O

-N h

a-1 d

-1)

UrineUrine + Eco-NControl


Reference Season Soil Location ofRainfall/ irrigation DCD EF3

Reduction in EF3 (%)

soil (mm/y) (%)

Di & Cameron (2002) Spring Lismore Canterbury 1,360 No 3.8 -Soil Use & Management 18, 395-403. Spring Lismore Canterbury 1,360 Yes 0.7 82

Di & Cameron (2003) Autumn Lismore Canterbury 850 No 2.2 -Soil Use & Management 19, 284-290 Autumn Lismore Canterbury 850 Yes 0.6 73

Autumn Lismore Canterbury 850 Yes 0.6 73Autumn Lismore Canterbury 850 Yes 0.4 82Spring Lismore Canterbury 850 No 1.5 -Spring Lismore Canterbury 850 Yes 0.4 73Spring Lismore Canterbury 850 Yes 0.4 73Spring Lismore Canterbury 850 Yes 0.2 87

Di & Cameron (2006) Autumn Lismore Canterbury 1,050 No 1.9 -

Biology & Fertility of Soils 42, 472-480. Autumn Lismore Canterbury 1,050 Yes 0.7 65

Autumn Lismore Canterbury 1,050 Yes 0.6 70Autumn Lismore Canterbury 1,050 Yes 0.5 73Spring Lismore Canterbury 1,050 No 2.6 -Spring Lismore Canterbury 1,050 Yes 0.7 73Autumn Templeton Canterbury 1,050 No 3.1 -Autumn Templeton Canterbury 1,050 Yes 1.2 61Autumn Templeton Canterbury 1,050 Yes 1.4 56

Di et al. (2007) Winter Templeton Canterbury 1100 No 2Soil Use & Management 23, 1-9. Winter Templeton Canterbury 1100 Yes 0.5 73

Autumn Lismore Canterbury 1100 No 0.8Autumn Lismore Canterbury 1100 Yes 0.3 63Autumn Horotiu Waikato 1100 No 0.6Autumn Horotiu Waikato 1100 Yes 0.2 67Spring Taupo Taupo 1100 No 0.1Spring Taupo Taupo 1100 Yes 0.02 80

Di et al. (2009) in press Autumn Lismore Canterbury 1100 No 3

Autumn Lismore Canterbury 1100 Yes 1.4 54Autumn Mataura Southland 1100 No 2Autumn Mataura Southland 1100 Yes 0.9 55Autumn Harihari West Coast 1100 No 1.9Autumn Harihari West Coast 1100 Yes 0.8 58Autumn Lismore Canterbury 2200 No 3.9Autumn Lismore Canterbury 2200 Yes 1 74Autumn Mataura Southland 2200 No 1.5Autumn Mataura Southland 2200 Yes 1 33Autumn Harihari West Coast 2200 No 1.4Autumn Harihari West Coast 2200 Yes 0.4 71

Average EF3 reduction (%) for all 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-improves-agriculture%E2%80%99s-green


Nitrate leaching losses


Soil lysimeter facilities in different regions

Canterbury: Templeton and Lismore

Waikato: Horotiu soil

Taupo pumice soil


DCD reduced nitrate leaching from a Canterbury Lismore soil (Di et al., 2009)

0

50

100

150

200

250

300

0 50 100 150 200 250 300 350

Cumulative drainage (mm)

NO

3- -N

co

nce

ntr

atio

n (

mg

L-1

)

UrineUrine + DCD


Urine only

Urine plus eco-n (May + Aug)

Nitrate leaching losses reduced in a range of South Island soils (Di et al. 2009)

0

100

200

300

400

500

600

Urine Urine +DCD

Urine Urine +DCD

Urine Urine +DCD

Urine Urine +DCD

Urine Urine +DCD

Treatments

NO

3- -N le

achi

ng lo

ss (k

g ha

-1)

1100 mm rainfall 2200 mm rainfall

Canterbury West CoastSouthland Southland West Coast

56% 67% 71% 44% 56%


Urine only

Urine plus eco-n (May + Aug)

Nitrate leaching losses reduced in North Island Soils Data from Shepherd et al. 2009 (AgResearch). FLRC Conference Proceedings.

0

100

200

300

400

500

600

700

urine urine+DCD urine urine+DCD urine urine+DCD urine urine+DCD

Treatments

NO

3- -

N leach

ing

lo

ss (

kg

ha-1)

Waikato Northland Waikato Northland

1100mm rainfall 2200mm rainfall

55% 35% 33%31%


AgResearch study showed DCD reduced nitrate leaching lost by between 21 and 56%, depending on the year of study (P < 0.05)

(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% North Island25-40% South Island

http://www.fertresearch.co.nz/code-of-practice/fact-sheets


DCD degradation and soil temperature

0

40

80

120

160

0 10 20 30

Temperature, deg C

Hal

f lif

e, d

ays

NZ data

International literature (4 studies)

Kelliher & Clough et al. Soil Biol. Biochem. 2008


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 ammonium-

oxidising 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.”

(O’Callaghan et al. 2010)


Pasture Production


Lincoln University

Control plot: no ‘eco-n’

Lincoln University

‘eco-n’ plot

Retaining more nitrogen in the soil can produce more pasture growth


National Trial Series shows significant increases in pasture growth from dicyandiamide. (132 data sets from 37 large on-farm grazed pasture trials)

Carey et al. (2011).


Thank you


Calculating DCD emission factors (EF)

0099.0)12

5

%100

%501()1(''1

months

monthsEFdefaultIPCCEFdefaultIPCCplusDCDEF

0079.0)12

5

%100

%503()3(''3

months

monthsEFdefaultIPCCEFdefaultIPCCnDCDplusEF PRPPRPPRP

kg N2O/kg fertiliser-N

kg N2O/kg excreta-N

(Clough et al. 2007 Nutr. Cycl. Agroecosyst. 78:1-14. )


Table 8 Module Submodule Worksheet Sheet

2003 Agriculture (New Zealand) Agricultural soils 4.5 (3 of 5) Direct nitrous oxide emissions from animal production (grazing animals)

Pasture, range and paddock AWMS

N excretion for AWMS

PRP (kg N)

Emission factor for

AWMS (EF3

PRP) (kg N2O-N/kg

N)

Total direct animal prodn.

emissions of N2O-N (Gg)

Total direct animal prodn.

emissions of N2O (Gg)

PRP nil DCD 1,386,897,313 0.0100 13.869 21.794 PRP plus DCD 143,375,290 0.0079

0.836 1.314

#Assumes 25% of dairy cattle under eco-n regime


114

116118

120

122

124126

128

130

0 10 20 30 40 50 60 70 80% dairy cattle under eco-n regime

N2O

em

issi

ons

rela

tive

to

1990

(%

)

nil eco-n

eco-n 5 month effective period

eco-n 5 month effective period but weighted emissions of 84%

Effect of eco-n on N2O inventory

new zealand’s specialist land-based university nitrous oxide and the nz ets prof. tim clough

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