Major J, B,
Nguyen
Lehmann
Lehmann
J, Rondon
J, Hockaday
M, Goodale
WC, Joseph
C (2010a)
S, Masiello
Fate ofCA
soil-applied
(2010) Temperature
black carbon:
sensitivity
downward
of black
migration,
carbonleaching
decomposition
and soiland
respiration.
oxidation.
Glob
Environ
Change
SciBiol
Tech16:1366-1379
DOI: 10.1021/es903016y
Modeling black carbon in the environment
Bente Foereid, Johannes Lehmann, Julie Major
Crop and Soil Sciences, Cornell University
•Black carbon (BC) is produced in fires and is assumed to be stable in the environment
•“Biochar” is BC intentionally produced for soil amendment
•BC has not yet been explicitly introduced into carbon turnover models
•Here we make a simple model accounting for loss of BC by decomposition and horizontal
as well as vertical movement out of the area
Results
Lab data for decomposition
2000
1800
-1
day )
1600
Measured
Simulated
0.5
1400
-2
2
y=1.452ln(x)-2.4599
r2=0.7094
1
2200
0
Model structure
Field data for leaching
1000
0.4
RMSD=0.24
20
40
0.2
0.1
0.0
Decomposition
CO2
600
400
30
Simulated
Measured
25
20
15-30 cm
15
10
60
Temperature (oC)
800
-2
0.3
-1
0
0-15 cm
1200
Black carbon in layer (g m )
3
CO2 production from BC (g CO 2-C m
Temperature modifier
4
2400
0.6
Nguyen et al., 2010 Environ Sci Tech 44, 3324–3331
Whitman , 2010 M.Sc. thesis, Cornell University
5
2600
100
200
300
400
500
600
700
800
5
Time since BC application (days)
Predicted and measured CO2
production. Data from Major et al.
2010
0
0
Added black carbon
2500
0-15 cm
2000
standard
stable pool decomposition rate
erosion rate
moisture modifier
temperature modifier
1500
CO2
Labile
Erosion
-1
15 cm
Major et al., 2010
Glob Change Biol 16:1366-1379
Stable
CO2
Labile
1000
Time since BC application (days)
Predicted and
measure BC in topand sub-soil. Data
from Major et al.
2010
500
0.3
30 cm
100 y
0.1
standard
erosion rate
slow pool decomposition rate
temperature sensitivity
400
0.2
Conclusions
600
0
15-30 cm
Leaching
400
500
BC in 0-30 cm soil (gm-2)
Stable
BC in soil layer (g m )
Erosion
200
300
2000 y
200
100
•Erosion is poorly quantified, but probably
Effect of changing parameter values, erosion
the largest flux of BC out of a given area
rate ± 50%, slow pool turnover rate 500-5000
•A two pool model can adequately
y, alternative values for temperature and
moisture modifier
describe BC decomposition dynamics
Next step – earth system model, CLM
•Decomposition rate of the slowest
carbon pool is unimportant on time-scales
< 100 y
•Downwards movement is small as a mass
flux, but not the only downward flux of
BC
0.0
0
0
20
40
60
Time since BC application (years)
80
100
0
500
1000
Time (years)
1500
2000