Modeling black carbon in the environmentBente Foereid, Johannes Lehmann, Julie Major

Crop and Soil Sciences, Cornell University

Lab data for decomposition

y=1.452ln(x)-2.4599r2=0.7094

Temperature (oC)

0 20 40 60

Tem

pera

ture

mod

ifier

-1

0

1

2

3

4

5

0-15 cm

0

500

1000

1500

2000

2500

standardstable pool decomposition rateerosion ratemoisture modifiertemperature modifier

15-30 cm

Time since BC application (years)

0 20 40 60 80 100

BC

in s

oil l

ayer

(g m

-1)

0.0

0.1

0.2

0.3

Conclusions•Erosion is poorly quantified, but probably the largest flux of BC out of a given area •A two pool model can adequately describe BC decomposition dynamics•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

Major et al., 2010 Glob Change Biol 16:1366-1379

Nguyen et al., 2010 Environ Sci Tech 44, 3324–3331Whitman , 2010 M.Sc. thesis, Cornell University

Time (years)

0 500 1000 1500 2000B

C in

0-3

0 cm

soi

l (gm

-2)

0

100

200

300

400

500

standarderosion rateslow pool decomposition ratetemperature sensitivity

•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

Stable

Stable

Labile

Labile

CO2

Leaching

Erosion Erosion

Decomposition

15 cm

30 cm

Added black carbon

CO2

CO2

0-15 cm

400

600

800

1000

1200

1400

1600

1800

2000

2200

2400

2600

15-30 cm

Time since BC application (days)

0 200 400 600

Bla

ck c

arbo

n in

laye

r (g

m-2

)

0

5

10

15

20

25

30

SimulatedMeasured

RMSD=0.24

Time since BC application (days)

100 200 300 400 500 600 700 800

CO

2 pr

oduc

tion

from

BC

(g C

O2-

C m

-2da

y-1)

0.0

0.1

0.2

0.3

0.4

0.5

0.6

MeasuredSimulated

Field data for leaching

Results

Predicted and measured CO2 production. Data from Major et al. 2010 Predicted and

measure BC in top- and sub-soil. Data from Major et al. 2010

Effect of changing parameter values, erosion rate ± 50%, slow pool turnover rate 500-5000 y, alternative values for temperature and moisture modifier

Major J, Lehmann J, Rondon M, Goodale C (2010a) Fate of soil-applied black carbon: downward migration, leaching and soil respiration. Glob Change Biol 16:1366-1379Major J, Lehmann J, Rondon M, Goodale C (2010a) Fate of soil-applied black carbon: downward migration, leaching and soil respiration. Glob Change Biol 16:1366-1379Major J, Lehmann J, Rondon M, Goodale C (2010a) Fate of soil-applied black carbon: downward migration, leaching and soil respiration. Glob Change Biol 16:1366-1379Major J, Lehmann J, Rondon M, Goodale C (2010a) Fate of soil-applied black carbon: downward migration, leaching and soil respiration. Glob Change Biol 16:1366-1379Major J, Lehmann J, Rondon M, Goodale C (2010a) Fate of soil-applied black carbon: downward migration, leaching and soil respiration. Glob Change Biol 16:1366-1379Nguyen B, Lehmann J, Hockaday WC, Joseph S, Masiello CA (2010) Temperature sensitivity of black carbon decomposition and oxidation. Environ Sci Tech DOI: 10.1021/es903016y

Next step – earth system model, CLM

Model structure

100 y 2000 y