Towards More Efficient Soil Carbon Measurement and Monitoring Alex. M c Bratney Budiman Minasny Australian Centre for Precision Agriculture Faculty of Agriculture Food & Natural Resources

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

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 Atmosphere 770 Vegetation 600 Oceans 40 000 Global NPP 57 Petagram = 10 15 g = 10 12 kg = 10 9 tonnes

Global organic C storage (0-1 m):

1,200 – 1,600 Petagrams

Soil carbonate carbon larger

Soil stores a lot of carbon 2 Globally NPP : 57 x 10 9 t C y -1 Edgeroi (150 000 ha): C org Storage (to 1m) : 13 x 10 6 t C IA Watson (427 ha) C org Storage (to 1m) : 25 x 10 3 t C

Globally NPP : 57 x 10 9 t C y -1

Edgeroi (150 000 ha):

C org Storage (to 1m) : 13 x 10 6 t C

IA Watson (427 ha)

C org Storage (to 1m) : 25 x 10 3 t C

Carbon Storage (0-1 m) (kg m -2 ) 1 = kg m -2 = 10 tonnes/ha C Storage Edgeroi 0 - 5 5 - 6 6 - 7 7 - 8 8 - 9 9 - 10 10 - 11 11 - 12 12 - 14 14 - 16 16 - 18 18 - 20 0 - 5 5 - 6 6 - 7 7 - 8 8 - 9 9 - 10 10 - 11 11 - 12 12 - 14 14 - 16 16 - 18 18 - 20

The win-win of storing carbon Results from StrucC – Malamoud, McBratney, Minasny & Field 2008

Results from StrucC – Malamoud, McBratney, Minasny & Field 2008

The proposition A soil carbon accounting and trading scheme

A soil carbon accounting and trading scheme

A soil carbon accounting and trading scheme Independent auditor Carbon Emitter Landholder Government Buy C offset Certified Carbon Emission Reduction credits Offsetting company soil carbon sequestration contract Carbon emission target Audit soil C at 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

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

Soil sampling ~ $100/profile

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

Cost per profile: $140

Variation of soil carbon with depth and across space

Changes over time 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 Total C (dag kg -1 ) SEQUESTRATION POTENTIAL

Changes over time 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

Solutions …… Cheaper measurement Defining the object Monitoring scheme Stochastic contracts

Cheaper measurement

Defining the object

Monitoring scheme

Stochastic contracts

Cheaper measurement Lab and field NIR/MIR, LIBS, INS Cheaper but less precise

Lab and field NIR/MIR, LIBS, INS

Cheaper but less precise

Cheaper measurement field NIR - profiler Cheaper but less precise

field NIR - profiler

Cheaper but less precise

Cheaper measurement field NIR – on-the-go Faster, one depth Cheaper but less precise

field NIR –

on-the-go

Faster, one depth Cheaper but less precise

Inelastic neutron scattering Wielopolski et al., 2008 Nondestructive System for Analyzing Carbon 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

What should the object be?

Paddock, landuse etc.

Need to measure  C

Monitoring scheme Scheme to measure  C with minimised known uncertainty

Scheme to measure  C with minimised known uncertainty

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

Too expensive?

Something simpler required

Need whole paddocks or properties

Nowley Liverpool Plains 2008 stratified random sampling 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

Total C kg/m 3 N 6-10 11-15 16-20 21-25 26-30 31-35

STRATUM Total Carbon (kg/m 3 ) Stratum 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 tonnes Total area of Nowley = 1570 ha

STILL TOO EXPENSIVE!!?

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.

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.

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 offset Certified Carbon Emission Reduction credits Offsetting company soil carbon sequestration contract Carbon emission target Audit soil C at 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

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

results N Total C kg/m3 1 - 16.60 16.61 – 20.48 20.49 – 22.99 23.00 – 27.05