This presentation was presented during the 2 Parallel session on Theme 3.1, Managing SOC in: Soils with high SOC – peatlands, permafrost, and black soils, of the Global Symposium on Soil Organic Carbon that took place in Rome 21-23 March 2017. The presentation was made by Mr. He Hongxing, from University of Gothenburg - Sweden, in FAO Hq, Rome

1. Re-wetting drained peatlands can reduce
large greenhouse gas emissions
Hongxing He, Åsa Kasimir
Department of Earth Sciences
University of Gothenburg
Global symposium on soil organic carbon
21-23 March 2017 FAO-Rome
1

2. Natural peatlands store carbon and plant
nutrients
C
N
N2O ≈ zero
CH4
Peat
CO2

3. C N
CO2
N2O
Ditch
CH4
Peat

4. Skogaryd
• Spruce forest on drained soil earlier used for agriculture
• >1 m deep fertile peat
• A lot of measurement data

5. Calibration data: 2007-2009:
• Net solar radiation
• Soil emission N2O and CO2
• Soil temperature
• Soil water
• Groundwater level
• NEE
• Soil energy flow
CoupModel
• One dimentional soil layered model
• Simulate water and energy flow; and C and N cycling
Hongxing He et al. (2016a), Ecological Modelling
Coupled heat and mass transfer model for soil-plant-atmosphere systems
Upscale 1951-2031:
• Tree ring derived biomass data
Hongxing He et al., (2016b), Biogeosciences

6. Four scenarios modelled by CoupModel
80 years
Increasing wetness
Spruce, ~40 ± 20
cm water depth
(business as usual)
Willow, ~20 ± 10
cm water depth
Reed canary
grass, ~10 ± 5
cm water depth
Wetland, (~0 cm)
water in the soil
surface
1 2 3 4

7. 7
Scenario prediction
Annual emissions of 80 years
CO2
-0,8 -0,6 -0,4 -0,2 0,0
CO2(MgCO2eqha-1yr-1)
0
10
20
Scenario 1 Spruce
Scenario 2 Willow
Scenario 3 RC Grass
Scenario 4 Wetland
N2O
Ground water level, meter
-0,8 -0,6 -0,4 -0,2 0,0
CH4
-0,8 -0,6 -0,4 -0,2 0,0
Emissions(MgCO2equha-1yr-1)
Groundwater level (m)
CO2
-0,8 -0,6 -0,4 -0,2 0,0
CO2(MgCO2eqha-1yr-1)
0
10
20
Scenario 1 Spruce
Scenario 2 Willow
Scenario 3 RC Grass
Scenario 4 Wetland
N2O
-0,8 -0,6 -0,4
Spruce GHG savings compared to Spruce
Willow 25%
Reed canary grass 44%
Wetland 7%

8. 8
Draining:
Peat decomposition increases more than plant growth

9. Message
• Re-wetting drained forests on
fertile peatlands can potentially
reduce GHG emissions by 44%.
Wetlands; 1/5 of Sweden area