Pat Bellamy, Peter Loveland, Ian Bradley,
Murray Lark (Rothamsted), Guy Kirk
Carbon losses from all
soils across England and
Wales 1978-2003
Nature 437, 245-248 (2005)
g.kirk@cranfield.ac.uk
Availability of Soil Surveys in Europe, 2000
1:250,000 scale
1:50,000 scale
The National Soil Inventory
Unbiased inventory of soil resources across England
& Wales at intersects of 5 km x 5 km grid
 Whole of E&W sampled in
1979-83 (5,662 sites)
 Approx. 40% of sites resampled: agricultural 1994-96,
non-agricultural 2002-03
 Organic carbon content of 015 cm soil (Corg) measured
 Sampling scheme designed to
detect changes of ± 2 g kg-1
Checks on methods – accuracy of
relocation
80
 Six surveyors instructed to
80
Site 2
60
60
60
40
40
40
20
20
20
0
Soil organic C content (g kg-1)
revisit 10 sites following
original protocols
 Locations recorded with
GPS; distance from target
measured subsequently
 Accuracy better than 20 m
on enclosed land, 50 m
on open land
 Given the variability of Corg
at this scale, this is
adequate
80
Site 1
0
80
10
50
0
0
80
Site 4
10
50
0
Site 5
60
60
40
40
40
20
20
20
0
80
10
50
0
80
Site 7
60
60
40
40
20
20
0
140
120
100
80
60
40
20
0
0
10
50
10
10
50
Site 8
50
Distance from original site (m)
0
10
0
250
200
150
100
50
0
0
Site 10
0
0
0
80
60
0
Site 3
50
10
50
Site 6
0
10 50
Site 9
0
10 50
Checks on methods – consistency of
lab. analyses
soils from original sampling
re-analysed in 2003
 Good agreement between
original and re-analysed
values with no systematic
deviation
(slope of reduced major axis
correlation = 1.05, concordance
correlation = 0.93)
500
Re-analysed Corg (g kg-1)
 Approx. 10% of archived
400
300
200
100
0
0
100
200
300
400
Original Corg (g kg-1)
500
Original soil organic carbon contents
(1978/83)
Original soil organic carbon contents
(1978/83) and rates of change
Li
th
om
or
p
Pe hic
Su
lo
rfa
B
G ce P ro sol
ro -w o w
un a dz n
d- ter ol
w g ic
at le
e
M rg y
an le
-m y
ad
Pe e
at
Co
De nife Ara
bl
ci ro
u
d
Ro u s B e
ta ou wo og
t s
Lo ion wo od
Pe w al o
rm la gr d
n a
Roane d h ss
ug nt ea
h gr th
gr as
Up
az s
la Up
nd la S ing
c
he nd ru
at gr b
h/ as
m s
oo
r
Rate of change
(g kg-1 yr-1)
Rates of change - grouped by
(a) soil type, (b) land use
(a) Soil type
(b) Land use
2
0
-2
-4
-6
Rates of change - grouped by
original Corg
(a) Arable/
(b) Permanent
rotational grass
grass
(c) Non-agricultural
Rate of change
(g kg-1 yr-1)
2
0
-2
-4
-6
-8
0
100
200 0
100
200 0
100
Corg (g kg-1)
200
300
400
500
Rates of change - grouped by
original Corg
All land uses
Rate of change
(g kg-1 yr-1)
2
0
-2
-4
-6
Eqn (1)
-8
0
100
200
300
400
500
Corg (g kg-1)
Eqn (1): Rate of change = 0.6 - 0.0187 Ч original C org
Original Corg (g kg-1)
2
1
0
-1
> 300
200-300
100-200
50-100
30-50
-3
20-30
-2
0-20
Rate of change, Mt yr-1
0
> 300
5
200-300
> 300
200-300
50-100
30-50
20-30
0
100-200
5
10
100-200
10
15
50-100
15
20
30-50
20
25
20-30
25
30
0-20
% of total OC stock
30
0-20
% of area of E&W
Estimated changes in carbon stocks
across England & Wales (and UK)
OC stock = Corg x BD x depth x area
where BD = 1.3 – {0.275 ln(Corg/10)}
Net rate of change in England & Wales = - 4.4 Mt yr-1
Net rate of change in UK ≈ - 4.4 x UK / E&W topsoil OC stock
≈ -13 Mt yr-1
-1
Pe
Rate
of
change,
Mt
yr
% of area
rm
Ro an
ta en Ara
tio t b
R
De ou na gra le
ci gh l g ss
du g ra
Co U ous raz ss
Up ni pla w ing
la fer nd oo
nd ou g d
he s wras
at o s
h/ od
m
Scoor
r
Boub
g
Changes in carbon stocks across
E&W – grouped by land use
40
30
20
10
0
1.0
0.5
0.0
-0.5
-1.0
-1.5
Dynamics of soil organic carbon
(SOC)
Plant
debris
CO2,
CH4
Carbon immobilization
(Fe, Al, clay
association)
Carbon mobilization
SOC ‘pools’
• fast
• intermediate
• slow
(high temperature,
rainfall, land use)
Carbon accumulation
input + immobilization >
< mobilization + output
Carbon loss
After Schultze, E.D. & Freibauer A. Nature 437, 205-206 (2005)
Leached
OC
Modelling soil carbon dynamics
SOIL POOLS
PLANT
DEBRIS
CO2
CO2
Fast SOC (C1)
decomp. rate = k1C1
Fast POC
Slow POC
CO2
CO2
Intermediate SOC (C2)
decomp. rate = k2C2
CO2
Slow SOC (C3)
decomp. rate = k3C3
Rate constants (ki) vary with soil temperature (T), moisture (θ), texture (t):
ki = f(T) f(θ) f(t) ki0
Su
rfa
Rate of change, Mt yr-1 % of area
Gr ce
ou -w B
nd at row
-w er n
at gle
e
Li P r g y
th od le
om zo y
or lic
Pe ph
lo ic
s
M
an Peol
-m at
ad
Ra e
w
Changes in carbon stocks across
E&W – grouped by soil type
40
30
20
10
0
0.5
0.0
-0.5
-1.0
-1.5
Most important soil types
Ah
A
E
Ah
Ea
Ea
Bh
Bh
Bs
Bs
BC&Ea
BC & Ea
B
BC&Bs BC & Bs
Surface water gleys
Podzolic soils
Peat soils
Slowly permeable,
seasonally wet
Acid sands or loams with
leached organic matter &
sesquioxides, wet or dry
Permanently or seasonally
wet
Modelling soil carbon dynamics
SOIL POOLS
PLANT
DEBRIS
CO2
CO2
Fast SOC (C1)
decomp. rate = k1C1
Fast plant OC
Slow plant OC
CO2
CO2
Intermediate SOC (C2)
decomp. rate = k2C2
CO2
Slow SOC (C3)
decomp. rate = k3C3
Rate constants (ki) vary with soil temperature (T), moisture (θ), texture (t):
ki = f(T) f(θ) f(t) ki0
Soil carbon map of Europe
Organic Carbon (%)
No Data
0-1
1-2
2-5
5 - 10
10 - 25
25 - 35
> 35
Data sources
Soil type
Land cover
Temperature
Rasterization
Soil type
Spatial layers derived by
rasterization of a
Triangulated Irregular
Network (TIN) model with
weighted distance
interpolation
Temperature
Future research
 Third sampling of NSI
- plus carbon fluxes (to air and water)
- plus additional data
 Modelling
- statistical
- semi-empirical
- predictive
 Similar studies elsewhere