improving the uk agricultural n o inventory...improving the uk agricultural n 2 o inventory (inven 2...

Improving the UK Agricultural N2O

inventory (InveN2Ory project)

Chris Adams [email protected] www.wensumalliance.org.uk

Chris Adams

Kevin Hiscock, Faye Outram

Dave Chadwick, Julian Andrews

http://www.defra.gov.uk/index.htm

Content • Background

– Current GHG inventory methodology

– Trends in Emissions

– Why we need to change our approach

• Nitrous Oxide: Sources + sinks

• Components of the new InveN2Ory project

– Direct Emissions

– Indirect Emissions and the DTC projects

• Preliminary Results

• Current and future work

www.wensumalliance.org.uk

Current UK agriculture N2O inventory methodology

• Essentially Tier 1

• Using year 1996 Guidelines, 2000 Good Practice Guidance

– IPCC standard Emission Factors (EFs)

– UK activity data

• livestock numbers

• fertiliser N use

• N excretion values

• Manure management systems


Trends in GHG emissions from UK agriculture

• Driven by change in stock numbers and fertiliser use

• Insensitive to farm system management and efficiencies

• Insensitive to adoption of abatement strategies


Why change to a Tier 2 approach? • Tier 1 is a blunt reporting tool

• UK set challenging targets

• Industry GHG roadmaps

• Need a reporting tool that better reflects: – Soil types

– Rainfall zones

– Management of nitrogen sources

– Specific mitigation strategies

• Apportion uncertainty to specific parts of the inventory www.wensumalliance.org.uk

The InveN2Ory project: improving the UK agricultural GHG inventory (nitrous oxide)

http://www.abdn.ac.uk/index.php

http://www.ceh.ac.uk/index.html

/

http://www.rothamsted.bbsrc.ac.uk/index.html

InveN2Ory - Aims

• To generate an improved N2O inventory that reflects the range of soil types, climate and N sources of UK agricultural systems

– To generate Tier 2 (and potentially Tier 3) emission factors through measurements and modelling

– To verify emission factors and inventory totals and test appropriate cost-effective mitigation methods.

• To quantify uncertainty of the improved N2O inventory, and ascribe to the different stages of inventory building

Generate an improved inventory for reporting and methodology to

track changes in N2O emissions against the challenging reductions

that have been set

• Direct N2O emissions (from soils)

– Soil type, soil wetness

– N form: urine, dung, manure type, fertiliser N types

– Rate of N application

– Timing of N application (RB209 +

• Country specific activity data (spatial/temporal)

• Indirect N2O emissions (drainage, rivers & groundwater)

– Country specific fracleach values

– Country specific N deposition


Components of the new InveN2Ory project

NH3 (g)

NH4+

Org-N

NO2-

NO3-

N2 (g)

N2O (g)

Crop Uptake

Fertiliser Grazing returns

Nitrogen fixation

Atmospheric deposition

Denitrification

Direct Emissions

from soils

Direct Emissions

Experimental Platforms ( )

and Soil Typology

• Selection of sites and treatment combinations

• Standard experimental protocols

– treatments, plot size, chamber design,

chamber deployment, sampling method,

sampling frequency, GC testing,

data handling

• Identification of proxies

– Soil parameters (for modelling at field scale)

• Modelling

Standard Experimental Protocols

Direct N2O emissions:

•static chambers (40 x 40 x 30 cm)

•5 chambers per plot (stackable)

•3 replicate plots per treatment

•Plots are zoned

•Up to 11 treatments per experiment

(up to 165 chambers per experiment)

•Chambers must be installed at least 24

hours before sampling

•Chambers remain in same position

Emission factor measurements Tillage land:

N fertiliser (45) (Gilchristan, Rosemaund,

Woburn)

Control

AN rate 1 (RB209 timings)



AN rate 4 (RB209 recommended rate, RB209 timings)

AN rate 5 (> RB209 rate, RB209 timings)

AN rate 4 (RB209 timings) + DCD

Urea at rate 4 (RB209 timings)

Urea at rate 4 + DCD

AN at rate 4 (5 splits instead of 3)

Livestock manure (7) (Rosemaund,

Wensum, Gilchristan)

Control

FYM Autumn

Poultry litter autumn

Poultry litter spring

Layer manure autumn

Layer manure spring

Slurry surface broadcast - autumn

Slurry trailing shoe – autumn

Slurry surface broadcast – spring

Slurry trailing shoe - spring

Fertiliser N rate vs N2O flux – arable

Site 2

y = 0.0089x + 1.0425

R2 = 0.92

Site 3

y = 0.02x + 2.5783

R2 = 0.82

0

1

2

3

4

5

6

7

8

0 100 200 300 400

Application rate (kg N ha-1

)

Cu

mu

lati

ve N

2O

(kg

N2O

-N h

a-1

)

Site 1 Site 2 Site 3

Site 1

y = 0.707 +

0.145 (1.00994x)

R2 = 0.95

Source: Project AC0101

WP2: Emission factor measurements

Grassland: N fertiliser (24)

(Hillsborough, Crichton, Pwllpeiran, Drayton, North Wyke)

1. Control

2. AN* 70 (RB209 timings)





7. AN* 210 (RB209 timings) + DCD

8. Urea 210 (RB209 timings)

9. Urea 210 (RB209 timings) + DCD

10 . AN* 280 (3 splits 1st cut, 2 splits 2nd and 3rd cut)

* N Ireland will use

CAN

Non-linearity of N2O emissions from fertilised grazed grassland

Year 1

Year 2

Agriculture, Ecosystems & Environment

Volume 136, Issues 3–4, 15 March 2010, Pages 218–

226


Year 1

Year 2



226

NH3 (g)

NH4+

Org-N

NO2-

NO3-

N2 (g)

N2O (g)

Crop Uptake


Nitrogen fixation


Denitrification

Direct Emissions

from soils

Indirect Emissions


Year 1

Year 2



226

NH3 (g)

NH4+

Org-N

NO2-

NO3-

N2 (g)

N2O (g)

Crop Uptake


Nitrogen fixation


Denitrification

Direct Emissions

from soils

Indirect Emissions

NH4+

NO2-

NO3-

N2O

NH3 (g)

NH4+

Org-N

NO2-

NO3-

N2 (g)

N2O (g)

Crop Uptake


Nitrogen fixation


N2O

Denitrification

Direct Emissions

from soils

Indirect Emissions

NH4+

NO2-

NO3-

N2O

NH3 (g)

NH4+

Org-N

NO2-

NO3-

N2 (g)

N2O (g)

Crop Uptake


Nitrogen fixation


N2O

Denitrification

Direct Emissions

from soils

Indirect Emissions

Indirect Emissions

NH4+

NO2-

NO3-

N2O

Indirect Emission factors

EF-5 groundwater, drainage, rivers, estuaries

• Method 1: Used by the IPCC

dissolved N2O / dissolved nitrate

Problems

NO3- can be reduced and utilised

N2O can be produced

consumed

degassed


(current estimates)

• Applied nutrients

• % of applied nutrients leached

IPCC 2006 default value of 0.3 (0.1–0.8)

• % of leached nutrients converted to N2O

and lost to the atmosphere


Indirect Emission factors

EF-5 groundwater, drainage, rivers, estuaries

• Method 2:

(current estimates)

Indirect Emissions • Work within the Defra Demonstration Test Catchment

(DTC) research platform to improve indirect EFs of N2O

Avon (Hampshire) Mixed lowland farming

Consortium includes ADAS, University of Reading, University of Bristol, QMUL,

ENTEC and others...

Wensum (Norfolk)

Arable farming Consortium includes

University of east Anglia, Scott Wilson, Cranfield

University, British Geological Survey, Entec,

NIAB and others....

Eden (Cumbria) Livestock & mixed

farming Consortium includes Lancaster University, Newcastle University, Durham University,

University of Cumbria, Eden Rivers Trust, CEH

and others....

Catchment wide sampling Land use and sampling points in

the Wensum catchment

Catchment nitrous oxide vs. nitrate:

Feb 2011 – March 2012

High range of emission factors

0

0.5

1

1.5

2

2.5

3

3.5

4

4.5

0 2 4 6 8 10 12

N2O

N µ

g L-1

NO3- N mg L-1

Feb '11 March '11 April '11 June '11 July '11 Aug '11 Sept '11 Oct '11 Nov '11 Dec '11 Jan '12 Feb '12 March '12 Atmospheric Equilibrium

0

20

40

60

80

100

120

140

160

0 2 4 6 8 10 12 14 16 18 20

W12 W11 W21 W14 W15 W16 W17 W18 W13 W20 W05 W06 W01 W02 W03 W04 W07 W08 W09 W10

Chalk

Till

Feb Mar Apr May June July Aug Sep Oct Nov Dec Jan Feb Mar Apr May June


Chalk

Till

16 months of catchment wide grab sampling in the Wensum (N2O and N species):


Improved indirect EF (Method 2)

• Applied N Land use, farm business survey data, general activity data

• % of nutrients leached Nutrient samples & EA flow

records

• % of leached nutrients converted to N2O and lost from the system

N2O measurements (air and water) gives both fluxes and EFs

Next steps

Summary: catchment wide sampling

• Gives significant improvements over current EFs and flux estimates

• BUT only covers a medium range of flow and drainage conditions

• Does NOT utilise the high resolution temporal data of the DTC projects


Wensum DTC mini-catchments

Sub-catchment sampling

● Nutrient and flow data: every 30 minutes

● N2O data at stations A-F: every week

● Hourly N2O data at A, B and E: every month

Sub-catchment sampling

0.4

0.6

0.8

1

1.2

1.4

1.6

1.8

400 500 600 700 800 900 1000 1100 1200 1300

A

B

E

Noon Dusk

Night

Minutes

µg

N2O

N L

-1

Diurnal patterns and in stream production of N2O

September 2011

Remaining Issues • N2O data not spatially robust due to uncertainty in in-

stream processes (N2O can be lost, used, produced or mixed)


Streams are not simply mixing but have multiple inputs along their courses

Remaining Issues • N2O data not spatially robust due to uncertainty in in-

stream processes (N2O can be lost, used, produced or mixed)


A

B

E

Limited

headwater

sampling

Field drains

Field drains

DTC mini sites

DTC high spec site

~300 m

Samples every 15-30 meters and at all main

field drains in DTC mini-catchments A, B and E

Remaining Issues

• N2O Measurements do not represent all flow conditions

• N2O data is IPCC compliant and at least as good as other studies but not as temporally robust as the high resolution nutrient data available from the DTCs

• Misses some key events


Rain event

Rain event

Storm event

Solutions: What now?

• Increased sample capacity

• New equipment

• Increased temporal resolution

–Diurnal sampling

– Increased sampling rain and storm events at DTC sites and field drains


Final Points

• New GHG Inventory being assembled

• Tier 2 Inventory : UK data, UK farms, UK activity

• Track changes in N2O emissions due to changing practices and future mitigation measure

• Reductions in GHG not limited to the gases themselves but integral to agricultural nutrients cycles and practices

• Requires projects like the DTC to feed back nutrient data but also to fully understand our varying catchments


More info:

• http://www.ghgplatform.org.uk/

• [email protected]

• [email protected]


http://www.ghgplatform.org.uk/



mailto:[email protected]@uea.ac.uk



Emission factor Default value Uncertainty range

EF1 Direct emissions from

managed soils. 0.01 0.003 – 0.03

EF3 Direct emissions from

livestock urine and

manure deposited by

grazing animals.

0.02 0.007 – 0.06

EF5g Indirect emissions

from groundwater 0.002

EF5r Indirect emissions

from rivers 0.0075

(EF5 total)

0.0005 – 0.025

EF5e Indirect emissions

from estuaries

0.0025

IPCC emission factors for N2O

Source: IPCC (2006)

• Used by the IPCC to estimate N2O fluxes

• Relate N2O fluxes to the nitrogen in the system

General, not regional or

catchment specific

Nitrogen leaching rate calculation Period: 21/3/11 00:00 to 27/3/11 15:00 (= 6.625 days) Mean flow rate = 0.045 m3/s Mean nitrate concentration = 6.25 mg N/L Nitrate-N flux = 24.3 kg N/day Leaching rate for mini-catchments A and B (579.8 ha) = 15.3 kg N/ha/a (~7 – 8 % of applied N amount) Leaching factor of 0.07-0.08 much lower than the IPCC value of 0.3 (0.1-0.9)


Example nitrous oxide flux and EF calculation Mean flow rate = 0.045 m3/s Dissolved N2O concentration = 1.06 µg N/L Dissolved N2O N flux = 0.004 kg N/day Emission factor for mini-catchments A and B : 0.004/24.3 = 0.00016 Lower than the IPCC value of 0.002


improving the uk agricultural n o inventory...improving the uk agricultural n 2 o inventory (inven 2...

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