Towards More Efficient Soil Towards More Efficient Soil Carbon Measurement and Carbon Measurement and

MonitoringMonitoring

Alex. McBratneyBudiman Minasny

Australian Centre for Precision AgricultureFaculty of Agriculture Food & Natural

Resources

Rationale

• Soil stores a lot of carbon• The win-win of storing carbon

Soil stores a lot of carbon 1

• Global organic C storage (0-1 m):

1,200 – 1,600 Petagrams

Soil carbonate carbon larger

0.01

0.1

1

10

100

C O

rg (

%)

-50 -40 -30 -20 -10 0 10 20 30 40 50 60 70

Lat

Atmosphere 770

Vegetation 600

Oceans 40 000

Global NPP 57

Petagram = 1015g = 1012 kg = 109 tonnes

Soil stores a lot of carbon 2

• Globally NPP: 57 x 109 t C y-1

• Edgeroi (150 000 ha): Corg Storage (to 1m) : 13 x 106 t

C• IA Watson (427 ha)

Corg Storage (to 1m) : 25 x 103 t C

0 - 5

5 - 6

6 - 7

7 - 8

8 - 9

9 - 10

10 - 11

11 - 12

12 - 14

14 - 16

16 - 18

18 - 20

Carbon Storage (0-1 m) (kg m-2)

1 = kg m-2 = 10 tonnes/ha 0 10,000 20,0005,000 Meters

K

Z

Slope

Aspect

TWI

Land Use

H1

H2

H3

Ca

Cb

k

Input Hiddenlayer

Output

ˆ ˆ expa bC C k z C

z0

0.2

0.4

0.6

0.8

1

1.2

1.4

0.0 0.5 1.0 1.5 2.0 2.5

C (kg m-3)

Dep

th (m

)

CALCAROSOL

CHROMOSOL

DERMOSOL

KANDOSOL

RUDOSOL

SODOSOL

VERTOSOL

Rudosol

Vertosol

Dermosol

Calcarosol

Kandosol

Chromosol

Sodosol

0 - 5

5 - 6

6 - 7

7 - 8

8 - 9

9 - 10

10 - 11

11 - 12

12 - 14

14 - 16

16 - 18

18 - 20

C Storage Edgeroi

The win-win of storing carbon

• Results from StrucCStrucC – Malamoud, McBratney, Minasny & Field 2008

FOM input

Per month

TYPE 1

CO2

CO2

Clay content

SOCm

Clay mass

Complexed clay

NCOC

RPM CO2 CO2

NCOC = f(SOC,clay)

TYPE 2

TYPE 3

Initial bulk density

CC = f(SOC,clay)

DPM

CO2

Non-complexed clay

Is used to calculate

Goes to

Lost

CO2

Fresh matter / pools calculated in the same manner as RothC-26.3

Aggregated and non-aggregated carbon pools

Struc-C

The proposition

• A soil carbon accounting and trading scheme

A soil carbon accounting and trading scheme

Independent auditor Carbon Emitter

Landholder

Government

Buy C offsetCertified Carbon Emission Reduction

credits

Offsetting company

soil carbon sequestrationcontract

Carbon emission target

Audit soil Cat beginning and end of

sequestration contract

soil carbon audit reporting trail

soil C auditing TOOL

(Research)

Advisor of Land management system

Management to optimise C sequestration

Ongoing Land Management and Soil Research

reporting

reporting

e.g. C-Lock

The problem

• Soil carbon is difficult and relatively expensive to measure and monitor

• Two aspects

Cost of measuring soil C

• Soil sampling ~ $100/profile

• Each profile: 4 layers, total C measurement: $40

• Cost per profile: $140

0

1

2

3

4

5

6

0 10 20 30 40 50

No. samples

Std

. d

ev.

C e

stim

ates

Variation of soil carbon with depth and across space

0

0.2

0.4

0.6

0.8

1

1.2

1.4

0 10 20 30 40 50

C (kg m-3)

Dep

th (

m)

Changes over time

0.0

0.5

1.0

1.5

2.0

2.5

0 5 10 15 20 25 30

No. years cleared

To

tal C

(d

ag

kg

-1)

C = 0.7 exp(-0.13 years) + 0.8

Odeh et al. (2002)

And by the way …..

0.0

0.5

1.0

1.5

2.0

2.5

0 5 10 15 20 25 30

No. years in irrigated cultivation

Tot

al C

(da

g kg

-1)

SEQUESTRATION POTENTIAL

General trend of total soil C storage decline ~0.6 kg m-2 in 20 years

Over the whole area (427 ha) ~ 2700 ton C

4

56

78

910

1112

C S

tora

ge (

kg/m

2)

1985 2007Year

Changes over time

Solutions ……

• Cheaper measurement

• Defining the object

• Monitoring scheme

• Stochastic contracts

Cheaper measurement

• Lab and field NIR/MIR, LIBS, INS

• Cheaper but less precise

Cheaper measurement

• field NIR - profiler

• Cheaper but less precise

Cheaper measurement

• field NIR –

• on-the-go

• Faster, one depth Cheaper but less precise

Inelastic neutron scattering

Wielopolski et al., 2008 Nondestructive System for AnalyzingCarbon in the Soil.Soil Sci. Soc. Am. J. 72, 1269-1277

Defining the object

• What should the object be?

• Paddock, landuse etc.

• Need to measure C

1 2t tC C C

2 1

1

A

C z z dA

x

x x x

Monitoring scheme

• Scheme to measure C with minimised known uncertainty

1 1 22 1 2 2t t t t t tV C V C C V C V C V C V C

Monitoring scheme

• Too expensive?

• Something simpler required

• Need whole paddocks or properties

Source: Australian Natural Resources Atlas

http://www.anra.gov.au/topics/soils/monitoring/index.html

Nowley Liverpool Plains 2008

stratified random stratified random

sampling schemesampling scheme

1 Crop

2 Drainage

1 Remnant

2 Crop

1 Pasture

2 Pasture

3 Crop

3 Drainage

3 Pasture

4 Crop

4 Remnant

5 Pasture

4 Pasture

Sample location

N

6-1011-1516-2021-2526-3031-35

Total C kg/m3

N

STRATUM Total Carbon

(kg/m3)Stratu

m Area %

Stratum Area (ha)

Carbon (Mg =

tonne)

4 cropping 13.4 34.5 247 33105

1 pasture 14.9 3.0 7 1086

4 pasture 15.1 1.7 169 25614

2 cropping 15.2 1.3 175 26532

2 drainage 16.6 16.0 10 1679

3 cropping 18.3 9.9 534 97741

3 drainage 18.4 10.9 46 8503

3 pasture 19.9 0.7 46 9212

1 cropping 20.5 4.5 12 2439

4 remnant veg 22.8 0.5 20 4459

1 remnant veg 23.0 11.3 70 16088

2 pasture 26.0 0.8 153 39821

5 pasture 27.1 5.1 79 21346

Total C to 1 m = 287 627 tonnesTotal area of Nowley = 1570 ha

• STILL TOO EXPENSIVE!!?

Carbon calculators

Indicative

Not accurate

Suggestion “Moral hazard reduction”

contracts

• Inevitable uncertainty in C.

• Pay carbon sequesterer on, say, lower 95% confidence value

• But if producer wants higher payment then he can invest in more measurement to reduce C uncertainty.

Latest developments

• We have a 3-year Australian Research Council Linkage project to work on this – awarded Oct. 2008, begins Mar. 2009

• Partners USyd ACPA, EES and 3DAg.

Summary

Independent auditor Carbon Emitter

Landholder

Government

Buy C offsetCertified Carbon Emission Reduction

credits

Offsetting company

soil carbon sequestrationcontract

Carbon emission target

Audit soil Cat beginning and end of

sequestration contract

soil carbon audit reporting trail

soil C auditing TOOL

(Research)

Advisor of Land management system

Management to optimise C sequestration

Ongoing Land Management and Soil Research

reporting

reporting

e.g. C-Lock

Conclusion

Soil carbon auditing as part of carbon emissions offsets trading

• There’s a good reason to do it

• There are some obstacles

• We need to find solutions quickly but we’re on the way

1 - 16.6016.61 – 20.4820.49 – 22.9923.00 – 27.05

results

N

Total C kg/m3