1. Modelling Soil Carbon Stock Changes
Pete Smith
Royal Society-Wolfson Professor of Soils & Global Change, FSB, FRSE
Institute of Biological & Environmental Sciences,
School of Biological Sciences,
University of Aberdeen,
Scotland, UK
E-mail: pete.smith@abdn.ac.uk
EPA Modelling Workshop, 24th November 2010, Dublin, Ireland

2. Outline
• Model development and application
• Case study 1: RothC application in the UK
• Case study 2: RothC application in Europe
• Case study 3: ECOSSE application using
UK LULUCF Inventory data
• Conclusions

3. Outline
• Model development and application
• Case study 1: RothC application in the UK
• Case study 2: RothC application in Europe
• Case study 3: ECOSSE application using
UK LULUCF Inventory data
• Conclusions

4. Models we use regularly
RothC DayCent / CENTURY
DNDC ECOSSE

5. Example publications on each model
• RothC
– Smith, J.U. et al. 2005. Projected changes in mineral soil carbon of European
croplands and grasslands, 1990-2080. Global Change Biology 11, 2141–2152.
• DayCent
– Yeluripati, J.B. et al. 2009. Bayesian calibration as a tool for initialising the
carbon pools of dynamic soil models. Soil Biology & Biochemistry 41, 2579-
2583.
• DNDC
– Hastings, A.F. et al. 2010. Uncertainty propagation in soil greenhouse gas
emission models: An experiment using the DNDC model at the Oensingen
cropland site. Agriculture, Ecosystems & Environment 136, 97-110.
• ECOSSE
– Smith, J.U. et al. 2010a. Estimating changes in national soil carbon stocks
using ECOSSE – a new model that includes upland organic soils. Part I.
Model description and uncertainty in national scale simulations of Scotland.
Climate Research (in press) doi: 10.3354/cr00899.
– Smith, J.U. et al. 2010b. Estimating changes in national soil carbon stocks
using ECOSSE – a new model that includes upland organic soils. Part II.
Application in Scotland Climate Research (in press) doi: 10.3354/cr00902.

6. Available (global) data:
Model development Flux data Isotope natural abundance
Soil representation in models: data
Long-term soil C experiment
networks
Soil respiration data N. America:
Europe:
86 Experiments
10 Experiments 20 Models
7 Models
Asia:
10 Experiments
1 Model
S. America:
3 Experiments
DGVMs Soil models Ecosystem models Africa:
3 Experiments Australasia:
e.g. e.g. RothC e.g. CENTURY, 8 Experiments
3 Models
JULES, DNDC DayCent, DNDC Isotope pulse labelling data
ECOSSE
CENTURY
Model evaluation:
2002
100 25
management b
90
a)
60.00 b
80
c passive 50.00 temperature
20 b
40.00
c slow 30.00 global radiation
% C Remaining
70 20.00
10.00 15
RMSE
60 c active 0.00 precipitation
-10.00 a
50
40 c metab
atmospheric CO2
concentration
10
a a a a a Improved
30
20
c struct
pH
bulk density
clay content
5
Process
10
0
0 1 2 3 4 5
Year
6 7 8 9 10
0
RothC
CANDY
DNDC DAISY
CENTURY SOMM
ITE NCSOIL
Verberne Description:

7. Outline
• Model development and application
• Case study 1: RothC application in the UK
• Case study 2: RothC application in Europe
• Case study 3: ECOSSE application using
UK LULUCF Inventory data
• Conclusions

8. RothC
co 2
RESIDUE
soil surface
DPM RPM BIO HUM
k=10 y
-1
k=0.3 y
-1
k=0.66 y
-1
k =0.02 y -1
IOM

9. RothC application to UK LULUCF Inventory
Falloon et al. (2006)

10. Outline
• Model development and application
• Case study 1: RothC application in the UK
• Case study 2: RothC application in Europe
• Case study 3: ECOSSE application using
UK LULUCF Inventory data
• Conclusions

11. Climate data: 2080-1990 temperature
Note: 2080 and 1990 are 30 year averages of 2051-2080 and 1961-1990 respectively

12. Climate data: 2080-1990 water balance
Note: 2080 and 1990 are 30 year averages of 2051-2080 and 1961-1990 respectively

13. Soils data – SOC

14. Soils data – Clay %

15. Data
• NPP and litter input data
– NPP calculated using LPJ-DGVM for ATEAM grid
(g C m-2) and used directly for croplands and
grasslands

16. Climate-only impact on cropland and grassland
SOC - (effect of different climate scenarios)
(HadCM3)
100
95
SOC stock (t C ha-1)
Grassland
90
85
Cropland
80
75
1990
2000
2010
2020
2030
2040
2050
2060
2070
2080
Year
A1FI B1 B2 A2
J.U. Smith et al. (2005)

17. Change in grassland SOC – climate only
J.U. Smith et al. (2005)

18. Change in cropland SOC – climate only
J.U. Smith et al. (2005)

19. Change in SOC
- climate only
Temperature
SOC
Water
balance
Note: 2080 and 1990 are 30 year averages of 2051-2080 and 1961-1990 respectively

20. Comparing climate-only with climate&NPP
effects for croplands & grasslands
(HadCM3-A2)
110
105
Grassland
100
SOC stock (t C ha-1)
95
90
85
Cropland
80
75
70
1990 2000 2010 2020 2030 2040 2050 2060 2070 2080
Year
Climate Only Climate and NPP
J.U. Smith et al. (2005)

21. Effect of technology
in croplands & grasslands
(HadCM3-A2)
110
110
105
105
100 Grassland
SOC stock (t(t C ha-1)
C ha -1)
100
95
95
90
SOC stock
90
85
85
Cropland
80
80
75
75
70
70
1990 2000 2010 2020 2030 2040 2050 2060 2070 2080
1990 2000 2010 2020 2030 2040 2050 2060 2070 2080
Year
Year
Minimum
Climate Only Climate & NPP Climate & NPP & Tech Maximum
J.U. Smith et al. (2005)

22. Change in grassland SOC – climate&NPP&technology
Climate only
J.U. Smith et al. (2005)

23. Change in grassland SOC – climate&NPP&technology
Climate&NPP&technology
J.U. Smith et al. (2005)

24. Change in cropland SOC – climate&NPP&technology
Climate only
J.U. Smith et al. (2005)

25. Change in cropland SOC – climate&NPP&technology
Climate&NPP&technology
J.U. Smith et al. (2005)

26. Climate impact on mineral SOC
• Our results suggest that increased productivity
due to climate change will counteract its negative
impacts
• Inclusion of improved technology (in arable and
cropland) suggests that SOC in mineral soils
might increase in Europe over the next 75 years
• Even in the worst case, climate change could
account for a maximum of 10% of the SOC loss
reported by Bellamy et al. (2005).

27. CO2 sink (t CO2 ha-1 yr-1)
-20
0
20
40
60
80
100
120
140
160
Cropland - agronomy
Cropland - nutrients
Cropland - tillage&residue
Cropland - water
Cropland - setaside&LUC
Cropland - agroforestry
Practice
section…
Grazing land -
nutrient&grazing&species
Degraded land restoration
Manure application
Sequestration under
energy crops
Organic soil restoration
More work on organic soils needed. Organic soil
restoration vs. mineral soil sequestration. See next
Data from: Smith et al. (2008)

28. Outline
• Model development and application
• Case study 1: RothC application in the UK
• Case study 2: RothC application in Europe
• Case study 3: ECOSSE application using
UK LULUCF Inventory data
• Conclusions

29. ECOSSE
Soil C & N, mineral, organo-mineral and organic soil
SOC change and GHG fluxes. Developed specifically
for the soils of Scotland & Wales. Now part of
JULES. Very suitable for Irish soils?

30. Independent evaluation – CO2 release
70
60
Soil
50
Soil with litter
with litter
and fertiliser
40
30
Respiration (mgCO2-C kg-1 soil)
20
10
20
0
measured
simulatred Soil only
15
Soil
with fertiliser
10
5
0
0 50 100 150 200 250 0 50 100 150 200 250
time (days)
Respiration rate during laboratory incubation (Foereid et al., 2004)

31. Independent evaluation
– soil ammonium and nitrate in a peat in Finland
2D Graph 1
120
100
simulated NO3-
simulated NH4+
80
nitrogen (kg/ha)
measured NO3-
60
measured NH4+
fertiliser application
40
20
0
0 20 40 60 80 100 120 140 160
time (weeks)
Ammonium and nitrate simulated by ECOSSE for a peat cultivated with spring barley in
southern Finland (60o49’N, 23o30’E).

32. Independent evaluation
– soil ammonium in a cultivated peat in Finland
Potatoes NH4
30
25
20
kg/ha
Measured
15
Modelled
10
5
0
1
6
11
16
21
26
31
36
41
46
51
56
61
66
71
76
81
86
91
96
101
106
111
116
121
126
131
136
141
146
151
156
161
166
171
176
181
Week
Soil NH4 in a peat cultivated with spring barley in Southern Finland (60o49’N, 23o30’E)
(Regina et al, 2004). Calculations by M.Aitkenhead, UoA

33. Independent evaluation
– nitrous oxide emissions from a cultivated peat in Finland
Barley N2O
5
4.5
4
3.5
3
kg/ha
Measured
2.5
Modelled
2
1.5
1
0.5
0
1
6
11
16
21
26
31
36
41
46
51
56
61
66
71
76
81
86
91
96
101
106
111
116
121
126
131
136
141
146
151
156
161
Week
N2O emissions for a peat cultivated with spring barley in Southern Finland (60o49’N, 23o30’E)
(Regina et al, 2004). Calculations by M.Aitkenhead, UoA

34. Independent evaluation –
Mass loss & N from litter bags – more to do
120 2.2
2.0
100 Red pine Red pine
1.8
80 1.6
1.4
60
1.2
40 1.0
in pine
in pine in hardwood
0.8
% mass remaining
in hardwood simulated
20
% nitrogen in material
simulated
0.6
0 0.4
2.2
100
2.0 Red maple
Red maple
80 1.8
1.6
60
1.4
40 1.2
1.0
20
0.8
0 0.6
88 89 90 91 92 93 94 95 96 88 89 90 91 92 93 94 95 96
time (year) time (year)
Mass loss from litterbag experiment in Nitrogen content in remaining material
Harvard forest, US (Magill & Aber, 1998) from litterbag experiment in Harvard
forest, US (Magill & Aber, 1998)
Calculations by B. Foereid, UoA

35. Data used to run the model
New data on land use change 20km2
NCMS (National
Countryside
Monitoring Scheme)
MLC (Monitoring
Landscape Change)
Spatial scale: Counties (1971)
Spatial scale: LA groupings
Time periods: 1947-1969,
1969-1980 Time periods: 1947-1973,
1973-1988

36. Wales
Scotland
2000-2009
2000-2009
al. (2010a)
Jo Smith et
-2 -2
Change in soil C (kt C (20km) (10yrs) -1 Change in soil C (kt C (20km) (10yrs) -1
0
10
20
30
0
10
20
30
-50
-40
-30
-20
-10
-60
-50
-40
-30
-20
arable -10 arable
grassland grassland
forestry forestry
to arable
to arable
natural semi-nat
arable arable
grassland grassland
ECOSSE
ECOSSE
forestry forestry
to grassland
to grassland
natural semi-nat
CEH
CEH
arable arable
grassland grassland
forestry forestry
to forestry
to forestry
natural semi-nat
arable arable
grassland grassland
forestry forestry
to semi-natural
to semi-natural
natural semi-nat
ECOSSE simulation of change in soil C ECOSSE simulation of change in soil C
-2 -2
(kt C (20km) (10yrs) -1 (kt C (20km) (10yrs) -1
-100 -100
-80 -80
-60 -60
-40 -40
-20 -20
20
40
60
80
100
20
40
60
80
100
0
0
-80
-60
-40
-20
-80
-60
-40
-20
-100
-100
0 0
20 20
40 40
(kt C (20km)-2 (10yrs) -1
(kt C (20km)-2 (10yrs) -1
:1
:1
R2 = 0.9666
R2 = 0.982
60 60
1 Line
1 Line
CEH estimates of change in soil C
CEH estimates of change in soil C
80 80
100 100
National simulations compare well with LULUCF inventory

37. ECOSSE run for whole UK
Simulated changes in
(a)
soil carbon
(kt C 20km-2 (10 years)-1) Richards et al. (2010)
Jo Smith et
al. (2010b)
Tier 3 modelling. Baseline runs, runs with mitigation measures applied – in all
cases with uncertainty quantified

38. Outline
• Model development and application
• Case study 1: RothC application in the UK
• Case study 2: RothC application in Europe
• Case study 3: ECOSSE application using
UK LULUCF Inventory data
• Conclusions

39. Conclusions
• There are a range of tier 3 models that can be used
for LULUCF inventories to estimate SOC change,
including RothC, DayCent, DNDC and ECOSSE
• Some of these models (DayCent, DNDC, ECOSSE)
also simulate GHG fluxes
• ECOSSE was developed to work on the more
organic soils found in Scotland and Wales (as well as
mineral soils) – more suitable for Irish soils?

40. Thank you for your attention