The document discusses soil erosion modeling tools and their significance in understanding soil carbon dynamics and the global carbon cycle. It highlights the importance of lateral fluxes and the cumulative effect of soil erosion as a carbon sink, which amounts to 90 Tg by the end of the observed period. Key factors influencing this sink include climate change, land use change, and the burial of eroded carbon in floodplains.

1. Soil erosion modelling tools
for the use in Earth system
Models
V.Naipal1, R.Lauerwald2, P.Ciais3, B.Guenet3, Y.Wang3
1 Ludwig-Maximilian University, Germany
2 Université Libre de Bruxelles, Belgium
3 Laboratoire des Sciences du Climat et de l'Environnement, CEA-CNRS-UVSQ,
France
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2. 2
INTRODUCTION CE-DYNAM RESULTS CONCLUSIONS
The importance of lateral fluxes in the global
carbon cycle

3. 3
INTRODUCTION CE-DYNAM RESULTS CONCLUSIONS
SOC sequestration and climate mitigation

4. Soil redistribution and C dynamics
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INTRODUCTION CE-DYNAM RESULTS CONCLUSIONS
Sediment and C fluxes at landscape level as represented in the model. Black arrows are
sediment fluxes while red arrows are C fluxes
Naipal et al., 2015, GMD
Naipal et al., 2016, ESD
Naipal et al., 2018, BGS
Naipal et al., 2019,
submitted GMD
Mineralization
Agriculture
Forest
Hillslope
Burial &
Dynamic replacement
Erosion
Transport/
Deposition
Export of sediment and
carbon fluxes
Import of sediment and
carbon fluxes

5. Modelling tools
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INTRODUCTION CE-DYNAM RESULTS CONCLUSIONS

6. The vertical discretization scheme
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Carbon density
Depth
Δz
Litter input Soil respiration
Net Erosion
layer-dependent
respiration
Carbon density
Depth
Δz
Litter input Soil respiration
layer-dependent
respiration
Sediment
export
Sediment
import
INTRODUCTION CE-DYNAM RESULTS CONCLUSIONS
Net Deposition
Hillslope

7. 7
The Rhine catchment
INTRODUCTION CE-DYNAM RESULTS CONCLUSIONS
Topography Soil erosion in the year 2005

8. 8
Erosion change during 1850-2005
INTRODUCTION CE-DYNAM RESULTS CONCLUSIONS

9. INTRODUCTION CE-DYNAM RESULTS CONCLUSIONS
Net Mineralization
21%
Hillslope
Floodplain
deposition
64%
Hillslope
deposition
37%
C erosion
1.02 Tg C year-1
Dynamic replacement
94%
Net
Mineralization
36%
POC export
0.25%
Hillslope
Net ecosystem productivity
163%
Floodplain
Net ecosystem productivity
68%
C budget 1995-2005
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10. INTRODUCTION CE-DYNAM RESULTS CONCLUSIONS
The erosion-induced C sink
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The effect of land use change only
Without erosion
With erosion
Erosion effect

11. INTRODUCTION CE-DYNAM RESULTS CONCLUSIONS
Conclusions
Soil erosion leads to a cumulative net C sink of 90 Tg by the end
of the period, which is equal to one fourth of the cumulative
land C sink of the Rhine without erosion.
It is important to take global changes such as climate change into
account to better quantify the net effect of erosion on the C
cycle.
The burial of eroded C in floodplains plays an essential role in the
strength of the erosion-induced C sink.
Initial climate and land cover conditions and the transient period
over which erosion under global changes takes place are
essential for the determination if soil erosion is a net C sink or
source and to what extent.
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