Case Study 1Canadian Prairies: Soil C management

Biophysical information

M. Boehm, B. McConkey & H. Janzen

Agriculture and Agri-Food Canada

How can we vertically integrate biophysical, economic, and policy analyses into credible mitigation programs?How can we vertically integrate biophysical, economic, and policy analyses into credible mitigation programs?

Kyoto Protocol created a need for GHG mitigation science and policy

but, the policy environment was uncertain

• Would the Kyoto Protocol include sinks? • Will Kyoto become international law?

Needed “no-regrets” policy options

1

1. Soil C management on the Prairies as GHG mitigation - background & national circumstances

2. Current knowledge and models

3. How models can contribute to further understanding

Outline

3

~80% of Canadian agricultural land is on the Prairies

4

with young grassland soils ...

Chernozems (Mollisols) withChernozems (Mollisols) withhigh organic C and N contentshigh organic C and N contentsChernozems (Mollisols) withChernozems (Mollisols) with

high organic C and N contentshigh organic C and N contents5

and young agriculture. Farmers and scientists arrived together

Photo: saskinteractive.usask.ca Photo: Henry Janzen 6

Shutt 1910Shutt 1910

Indian Head Experimental Farm, 1899

Indian Head Experimental Farm, 1899

and the impact of agriculture on SOC and land quality was documented

Photos: saskinteractive.usask.ca 7

1900 1920 1940 1960 1980 20000

10

20

30

40

50

So

il C

(M

g C

ha-1

)

~ Initialcultivation

Ellert and Janzen (unpubl.)

Organic C in surface soil (2000 Mg)

Cereal-fallow rotation

Indian Head Experimental FarmIndian Head Experimental Farm

Early research led to recognition that maintaining SOC (soil conservation) is a key to maintaining land quality …

8

No agricultural country has ever prospered for more than a generation or two that has not made provision for maintaining the nitrogen and organic matter content of the soil.

No agricultural country has ever prospered for more than a generation or two that has not made provision for maintaining the nitrogen and organic matter content of the soil.

John Bracken. 1920Professor, Univ. Sask.

John Bracken. 1920Professor, Univ. Sask.Photo – Henry Janzen

Changes in land management that farmers are making for economic and conservation reasons

have become GHG mitigation strategies

9

… and now, SOC is also linked to atmospheric quality

0

2

4

6

8

10

12

1991 1996 2001

ZT

SF

Million haMillion haReduced summerfallow Minimum and ZTPermanent cover Forage production

But, agriculture most soil sinks only recover CO2 that was emitted after cultivation – not an offset for fossil emissions

Grassland

Conventional tillage

energyenergy

productproduct

CO2CO2

OrganicOrganicmattermatter

CC

Ecosystemboundary

Ecosystemboundary

NO3-NO3-

N2N2

fertilizerfertilizer

energyenergy

NN

N2ON2O

CH4CH4

and GHG mitigation through land managementis more than C sequestration

11

• Land has to be managed for net GHG removals

• Agriculture is a biological production system •The C and N cycles are linked

Current models and knowledge

12

Depth

(cm)

1996 to 1999 SOC change (Mg ha-1)

Prairie Soil Carbon

Balance Project

Measurements

CENTURY

Simulation

of PSCB

fields

C factors from

long-term experiments

IPCC

Guidelines (1996)

Mean 95% C.L

0-15 -- 1.05 --

0-20 1.02 +/-0.67 0.91 -- --

0-30 1.21 +/-0.80 -- -- 0.97

Reasonable understanding of SOC change

N2O emission rates more uncertain

Canadian Economic and Emission Model for Agriculture (CEEMA)

• Policy tool – estimate national GHG mitigation potential• Canadian Regional Agricultural Model + GHG module

13

75

SINK PRAIRIE SOIL ZONES NON-ACTIVITIES BRN D BRN BLK PRAIRIES (Mg CO2 ha-1 yr-1)

Zero Tillage 0.73 0.73 1.34 0.54Reduce SF* 0.15 0.16 0.08 Increase forage 0.94 2.44 2.44Permanent cover 0.88 1.15 3.3 3.3

SINK PRAIRIE SOIL ZONES NON-ACTIVITIES BRN D BRN BLK PRAIRIES (Mg CO2 ha-1 yr-1)

Zero Tillage 0.73 0.73 1.34 0.54Reduce SF* 0.15 0.16 0.08 Increase forage 0.94 2.44 2.44Permanent cover 0.88 1.15 3.3 3.3

Mt CO2e

BAU emissions

35

40

45

50

55

60

65

70

75

1990 1999 2010

C management mitigation potentialfor first commitment period

15

BAU sinks

Additional sinks e.g. offset trading

Next generation of models – greater spatial and activity resolution

• NCGAVS - National Greenhouse Gas and Carbon Accounting and Verification System (for agriculture)

• Component of the national Land Use, Land-use Change and Forestry - Measurement, Accounting and Reporting System LULUCF MARS

• Reporting LULUCF sector E/R under the UNFCCC and Kyoto Protocol

• Mitigation testing• Develop factors – eg., for offset system protocols

16

SLC Polygon Land Use-

Management Database

Regional Account (Grouped SLC Polygons)

ProvincialAccount

NationalAccount

Carbon sink/source and N2O Accountfor SLC Polygon

SLC Polygon Land Quality

Database

Factors - Estimators of SOCand N2O emissions

+

SLC Land Use-Management-Landscape – N2O- C

Database

NCGAV System

Ag. CensusAg. CensusRemote sensingRemote sensing

CanSISCanSIS

18

SoilsSoils

C and N2O Factors

CenturyCenturyDAYCENT DAYCENT

DNDCDNDCEmpirical dataEmpirical data

CenturyCenturyDAYCENT DAYCENT

DNDCDNDCEmpirical dataEmpirical data

19

Activity changes:• Tillage (eg., ZT, minimum till)• Summerfallow frequency• Perennial crops• Crop mix

LandscapeLandscape

Activity change Activity change

HistoryHistory

Regional Account (Grouped SLC Polygons)

ProvincialAccount

NationalAccount

Carbon sink/source and N2O Accountfor SLC Polygon

SLC Polygon Land Database

SLC Polygon Land Use-

Management Database

Factors - Estimators of SOCand N2O emissions

+

SLC Land Use-Management-Landscape – N2O- C

Database

NCGAV System

21

Scale up or drill down

Factor x Area

22

What can modeling contribute to what we don’t know yet?

It can held us look beyond laboratory research and field plots

• scale across space and time• integrate across systems – net GHG emissions• estimate uncertainty

24

Integration: Model Farm Research Project

25

• systematically integrate what we know • predict emissions as a function of farm properties/practices and land quality• establish boundaries and assess leakage associated with a change in management

• address gaps – i.e., research to reduce (large) uncertainty around N2O emissions

• better factors – net GHG emissions/removals and “rules of thumb”

Regional Account (Group of SLC Polygons)

ProvincialAccount

NationalAccount

Carbon sink/source and N2O Accountfor SLC Polygon

Soil Landscapes of Canada (SLC)Polygon Land Database

SLC Polygon Land Use-Management Database

Estimators soil carbon changeAnd nitrous oxide (N2O) emissions

+

SLC Land Use-Management-Landscape –N2O-C Change

Database

Regional Account (Group of SLC Polygons)

ProvincialAccount

NationalAccount

Carbon sink/source and N2O Accountfor SLC Polygon

Soil Landscapes of Canada (SLC)Polygon Land Database

SLC Polygon Land Use-Management Database

Estimators soil carbon changeAnd nitrous oxide (N2O) emissions

+

SLC Land Use-Management-Landscape –N2O-C Change

Database

National AccountUncertainty

Provincial AccountUncertainty

Pro

ba

bili

ty (

%)

Pro

ba

bili

ty (

%)

Pro

ba

bili

ty (

%)

Pro

ba

bili

ty (

%)

Uncertainties in Land Use-ManagementUncertainties in

Land Information

Pro

ba

bili

ty (

%)

Uncertainties in Factors

Estimating uncertainty

Monte Carlo Estimation

27

Making decisions under uncertainty

Is soil carbon management good mitigation policy?

Pro

bab

ility

(%

)

National Soil Carbon Account Uncertainty

Pro

bab

ility

(%

)

National Soil Carbon Account Uncertainty

Pro

bab

ility

(%

)

National Soil Carbon Account Uncertainty

28

Answer will depend on the cost and efficacy of alternatives

Representing timeO

rgan

ic C

Time

Old management New management

26

Steady-state?

verification?

SOC content?

2000 2010 2020 2030 2040 2050

0removeremove

ReplaceReplace

reducereduce

An

nu

al i

mp

act

of

mit

igat

ive

stra

teg

ies

(rel

ativ

e to

bu

sin

ess-

as-u

sual

)

What can our models contribute to what we don’t know yet - new mitigation strategies