uruguay reducing n o emissions from grazed pasture … · tim clough lincoln university new zealand...

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18/08/2008 1 Reducing N 2 O emissions from grazed pasture systems and options for including these in national inventories Tim Clough Lincoln University New Zealand URUGUAY N 2 O emissions: 9.7 MtCO 2 -e Desechos Excremento humano 1% Agricultura - Suelos agrícolas (Emisiones directas)6% Agricultura - Suelos de pastoreo (Emisiones - 99% of N 2 O emissions in 2002 originated in agriculture, - 90% of them from grazing animals (dung and urine deposited by free-range grazing animals). Agricultura - Suelos agrícolas (Emisiones indirectas)33% pastoreo (Emisiones directas por excreta de animales)60% (Luis Santos 2007) 2 2 2 N O N NO NO Denitrification N 2 O formation pathways 2 2 2 2 3 O N N NO NO OH NH NH 3 NO O N 2 Pathway: Nitrifier Denitrification Nitrification Denitrification Wrage et al. 2001 Soil Biology & Biochemistry NH 4 + ---- NO 3 - Cation exchange

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18/08/2008

1

Reducing N2O emissions from grazed pasture systems and options for including these in

national inventories

Tim Clough

Lincoln UniversityNew Zealand

URUGUAYN2O emissions: 9.7 MtCO2-e

Desechos Excremento humano1%

Agricultura -Suelos agrícolas (Emisiones directas)6%

Agricultura - Suelos de pastoreo (Emisiones

- 99% of N2O emissions in 2002 originated in agriculture, - 90% of them from grazing animals (dung and urine deposited by free-range grazing animals).

Agricultura - Suelos agrícolas (Emisiones indirectas)33%

pastoreo (Emisiones directas por excreta de animales)60%

(Luis Santos 2007)

222 NONNONO →→→−

Denitrification

N2O formation pathways

22223 ON NNONOOHNHNH →→→→→ −

3NOON2

Pathway: Nitrifier Denitrification

NitrificationDenitrification

Wrage et al. 2001 Soil Biology & Biochemistry

NH4+

- - - -

NO3-

Cation exchange

18/08/2008

2

Factors affecting denitrification rates in soils

Manage-

TemperatureTemperature

pHpH

DenitrificationDenitrificationNONO33 →→ NN22O & NO & N22

Soil type

Stocking rate Stocking type

Manage-ment

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

90

120

150

ion

(mg

N/L

)

Urine 1x500Urine 1x1000Urea 4x100

Nitrate leaching is greatest below the animal urine patch

Over 90% of total leaching in grazed

pasture comes from urine patches.

0

30

60

90

0 200 400 600 800

Cumulative drainage (mm)

Nitr

ate

N c

once

ntra

ti Control

< 10% of leaching comes from fertiliser

N2O emissions from urine amended soil

Canterbury moderately drained silt loam

0.8

1.0

1.2

g N

/m2 . h

our)

Cow urine

Control

0.0

0.2

0.4

0.6

9-Apr-00 28-May-00 16-Jul-00 3-Sep-00 22-Oct-00 10-Dec-00 28-Jan-01 18-Mar-01

Date

N2 O

em

issi

on (m

g

Source: Sherlock et al. (unpubl. data)

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How can we mitigate N2O emissions from excreta N?

• Change the animals diet?– modify the C/N ratio?

• Stand-off/feed pads?

Covered feed & loafing pad

(Cecile De Klein, AgResearch 2008)

Uncovered feed & loafing pad

(Cecile De Klein, AgResearch 2008)

How can we mitigate excreta N?

• Change the animals diet?– Increase C and modify the C/N ratio?– Stand-off/feed pads

Use nitrification inhibitors e g dicyandiamide– Use nitrification inhibitors e.g. dicyandiamide (DCD)

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4

Nitrosomonas

Nitrification inhibitor

DCD reduces the activity of the Nitrosomonas bacteria in the soil

(Bacteriostatic effect)

Ammonium + oxygen Nitrite

(NH4+)

Nitrobacter

Nitrite + oxygen Nitrate (NO3

-)

Nitrous oxide gas loss

Nitrate leaching loss

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

NH4+

- - - -

NO3-

Cation exchange

Nitrification inhibitor slows

down the rate of nitrate

production and thus reduces the nitrate leaching

loss

Recommend DCD is applied in May and August because most losses occur between late autumn and early spring

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

35

40

45

50

age

(mm

)

14

16

18

20

ure

C)

DCD DCD

0

5

10

15

20

25

30

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

Est

imat

ed D

rain

a

0

2

4

6

8

10

12

Soil

Tem

pera

tu0C

Drainage (mm)

Soil Temp (C)

Drainage

18/08/2008

5

Daily N2O-flux, Templeton lysimeters Winter Run Off Trial - 2005/06

500

600

700

800

(g/h

a/da

y)

Control

eco-n (10) 21st June

U1000 (3rd June)

U1000 (3rd June) eco n (10) 21st

DCD reduced N2O emissions by 73% on Templeton soil in Canterbury, NZ (Di et al. 2007).

0

100

200

300

400

9/06/2

005

24/06

/2005

9/07/2

005

24/07

/2005

8/08/2

005

23/08

/2005

7/09/2

005

Sampling date

N2O

-N fl

ux ( U1000 (3rd June) eco-n (10) 21st

N2O emissions reduced by 67% in the Canterbury Lismore soil (Di et al., 2007)

300

400

O-N

ha-1

day-1

) Urine 1000

Urine 1000 + DCD

0

100

200

29/04/05 29/05/05 28/06/05 28/07/05 27/08/05 26/09/05Sampling date

Dai

ly N

2O fl

ux (g

N2

N2O emissions reduced by 61% in the Waikato Horotiu soil (Di et al., 2007)

300

400

N2O

-N h

a-1 da

y-1) Control

Control + DCDUrine 1000Urine 1000 + DCD

0

100

200

05/05/05 04/06/05 04/07/05 03/08/05Sampling date

Dai

ly N

2O fl

ux (g

N

N2O emissions reduced by 69% in the Taupo pumice soil lysimeters (Di et al., 2007)

40

50

N h

a-1 d

ay-1

)

ControlControl + DCDUrine 700Urine 700 + DCD

0

10

20

30

3-Aug-05 2-Sep-05 2-Oct-05Sampling date

Dai

ly N

2O fl

ux (g

N2O

-N

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6

Nitrate leaching reduced by 76% from urine applied to Templeton soil (Di and Cameron, 2004. NZ J Agr. Res. 47)

60

80

100

tion

(mg

L-1)

Urea 200/Urine 1000

Urea 200/Urine 1000/Eco-N (May + Aug.)

0

20

40

60

0 50 100 150 200 250 300

Cumulative drainage (mm)

NO

3- -N c

once

ntra

Nitrate-N Leaching - Waihora, Taupo

250

300

350

400

/ha/

yr)

Urine alone

Urine + eco-n

no urine

no urine + eco-n

DCD reduced nitrate

leaching by 30 – 40%

3 year trial shows that DCD inhibitor significantly reduced nitrate leaching losses from Taupo pumice soils

0

50

100

150

200

2003 2004 2005 3 year AverageN

itrat

e-N

(kg

N/

Soil lysimeter facilities in different regions

Waikato: Horotiu soil

Canterbury: Templeton and Lismore Taupo pumice soil

Lincoln UniversityControl plot

Lincoln UniversityDCD plot

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7

Internationally peer reviewed and published literature:

• Di, H.J., Cameron, K.C., 2002. The use of a nitrification inhibitor, dicyandiamide (DCD), to decrease nitrate leaching and nitrous oxide emissions in a simulated grazed and irrigated grassland. Soil Use and Management 18, 395-403.

• Di, H.J., Cameron, K.C., 2003. Mitigation of nitrous oxide emissions in spray - irrigated grassland by treating the soil with dicyandiamide, a nitrification inhibitor. Soil Use and Management 19, 284-290.

• Di, H.J., Cameron, K.C., 2004a. Effects of the nitrification inhibitor dicyandiamide on potassium, magnesium and calcium leaching in grazed grassland. Soil Use & Management 20 2-7Management 20, 2 7.

• Di, H.J., Cameron, K.C., 2004b. Treating pasture soil with a nitrification inhibitor, eco-nTM, to decrease nitrate leaching in a deep sandy soil under spray irrigation - a lysimeter study. New Zealand Journal of Agricultural Research 47, 351-361.

• Di, H.J., Cameron, K.C., 2004c. Effects of temperature and application rate of a nitrification inhibitor, dicyandiamide (DCD), on nitrification rate and microbial biomass in a grazed pasture soil. Australian Journal of Soil Research 42, 927-932.

• Di, H.J., Cameron, K.C., 2005. Reducing environmental impacts of agriculture by using a fine particle suspension nitrification inhibitor to decrease nitrate leaching from grazed pastures. Agriculture, Ecosystems and Environment 109, 202-212.

• Di, H.J., Cameron, K.C., 2006. Nitrous oxide emissions from two dairy pasture soils as affected by different rates of a fine particle suspension nitrification inhibitor, dicyandiamide. Biology and Fertility of Soils 42, 472-480.

Some of the data required to develop an N2O inventory consists of:

• Animal numbers• N excreta• Direct emission factors• Direct emission factors

– EF1 N2O emitted from fertiliser

– EF3PRP N2O emitted from urine and dung

• Indirect emission factors– EF5 N2O emitted from leached N

2006 IPCC guidelines for National Greenhouse Gas Inventories

For a mitigation to be included in an inventory we also must know:

• Animal numbers affected by mitigation tool?

• Changes in N excreted?• Time period of the year mitigation tool

works?• Changes in direct emission factors ?• Changes in indirect emission factors ?• Verification?

Summary of international peer reviewed literature: DCD effect on

direct N2O emissions

• The reduction in direct N2O emissionsEF3(PRP) averaged 67% ± 6% (std dev. n=4.)

18/08/2008

8

Summary of international peer reviewed literature:

DCD effect on NO3- leaching

• The reduction in nitrate leaching Frac(LEACH) averaged 74% ± 4% (std dev. n=5.)

Calculating DCD emission factors (EF)

0099.0)125

%100%501()1(''1 =××−=

monthsmonthsEFdefaultIPCCEFdefaultIPCCplusDCDEF

kg N2O/kg fertiliser-N

0079.0)125

%100%503()3(''3 =××−=−

monthsmonthsEFdefaultIPCCEFdefaultIPCCnDCDplusEF PRPPRPPRP

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

Emission factor for

AWMS (EF

Total direct animal prodn.

i i

Total directanimal

dPRP (kg N)

AWMS (EF3

PRP) (kg N2O-N/kg

N)

emissions of N2O-N (Gg)

prodn.emissions

of N2O (Gg)

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

0.836 1.314

#Assumes 25% of dairy cattle under DCD regime

126128130

to 1

990

(%)

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

Effect of DCD on N2O inventory

114116118120122124

0 10 20 30 40 50 60 70 80% dairy cattle under DCD regime

N2O

em

issio

ns r

elat

ive

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Verification ???

GPS certified records of DCD application

DCD application map – providing proof of placement

Date and time of application

Paddock details

Customer details

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GPS certification of DCD application:

Dates & areas

Cow numbers:

Dates & areas

New Zealand default and/or DCD Emission factors

Fertiliser usage/application:

(Fertiliser receipts)

Peer reviewed science

Calculate farm N2O flux(Fertiliser receipts)

Dates & areas

Calculate mitigation achieved

Calculate Carbon credit

$ $ $ $ $

$ $ $ $ $

Extra Dry Matter$

Summary• Identify main N2O sources and mitigation strategy.• Peer reviewed science of mitigation tool.

– Changes in N excreted?– Duration of mitigation effect(s)?– Changes in direct emission factors ?– Changes in indirect emission factors ?

• Verification.– Animal numbers affected by mitigation tool?– Land area affected by mitigation tool - Use technology!

e.g. GPS.

18/08/2008

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DCD degradation and microbiology

• Soil bacteria utilise and degrade DCD.

• Numbers of nitrifiers not affected.

f ff C• N2-fixers not affected by DCD.

• Repeat application of DCD in laboratory studies has little or no effect on rate of DCD decomposition or ability of DCD to inhibit nitrification.

• Moir et al. (2007, Soil Use & Mgt) shows no change in response to DCD after four years of field data collection in NZ.

DCD degradation and soil temperature

120

160

days

Di & Cameron 2004

0

40

80

0 10 20 30

Temperature, deg C

Hal

f life

, d

International literature (4 studies)

Kelliher & Clough et al. 2008

Internationally peer reviewed and published literature:

• Di, H.J., Cameron, K.C., 2002. The use of a nitrification inhibitor, dicyandiamide (DCD), to decrease nitrate leaching and nitrous oxide emissions in a simulated grazed and irrigated grassland. Soil Use and Management 18, 395-403.

• Di, H.J., Cameron, K.C., 2003. Mitigation of nitrous oxide emissions in spray - irrigated grassland by treating the soil with dicyandiamide, a nitrification inhibitor. Soil Use and Management 19, 284-290.

• Di, H.J., Cameron, K.C., 2004a. Effects of the nitrification inhibitor dicyandiamide on potassium, magnesium and calcium leaching in grazed grassland. Soil Use & Management 20 2-7Management 20, 2 7.

• Di, H.J., Cameron, K.C., 2004b. Treating pasture soil with a nitrification inhibitor, eco-nTM, to decrease nitrate leaching in a deep sandy soil under spray irrigation - a lysimeter study. New Zealand Journal of Agricultural Research 47, 351-361.

• Di, H.J., Cameron, K.C., 2004c. Effects of temperature and application rate of a nitrification inhibitor, dicyandiamide (DCD), on nitrification rate and microbial biomass in a grazed pasture soil. Australian Journal of Soil Research 42, 927-932.

• Di, H.J., Cameron, K.C., 2005. Reducing environmental impacts of agriculture by using a fine particle suspension nitrification inhibitor to decrease nitrate leaching from grazed pastures. Agriculture, Ecosystems and Environment 109, 202-212.

• Di, H.J., Cameron, K.C., 2006. Nitrous oxide emissions from two dairy pasture soils as affected by different rates of a fine particle suspension nitrification inhibitor, dicyandiamide. Biology and Fertility of Soils 42, 472-480.

18/08/2008

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Scale – 20 cm x 20 cm = 400 cm2Scale – 20 cm x 20 cm = 400 cm2

Nitrosomonas bacteria are widespread throughout the soil and they all need to be treated.

18/08/2008

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