Soil organic carbon sequestration potential for croplands in Finland
Scientists at the Natural Resources Institute Finland (Luke) have investigated the extent and rates of SOC sequestration potential between 2021-2040 under different scenarios of climate change and Sustainable Soil Management (SSM) practices.
The researchers quantified the impacts of carbon inputs and climate change on SOC sequestration for croplands across Finland at a resolution of 1 km as a part of CarboSeq project. Firstly, the annual plant carbon inputs were calculated. Then a soil carbon model (RothC) was run to calculate the size of the SOC pools under different scenarios of climate change and SSM practices. Finally, factorial simulation experiments were conducted to quantify the impacts of climate change and SSM practices, alone and in combination, on SOC sequestration potential (Fig.1).
Under the combined impacts of climate change and SSM practices, the SOC sequestration potential during 2021-2040 relative to 2020 is on average -0.03 t C ha-1 yr-1 with carbon input being unchanged, and 0.13 t C ha-1 yr-1 with a 20% carbon input increase. Therefore, a 20% increase in C input to soil will not be enough to obtain a 4 ‰ increase per year over the 20-year period in Finland. Carbon input promotes SOC sequestration potential, but climate change will reduce it.
Across the cropland in Finland, on average, the relative contributions to SOC sequestration potential will be 56% for carbon input, 24% for temperature change, and 20% for precipitation change (Fig.2). The SOC sequestration potential will be relatively high and dominated by carbon input in west and southwest Finland. By contrast, it will be relatively low and dominated by climate in north and east Finland, and the central part of southern Finland.
These findings provide the information as to where, how much, and which SSM practices could be applied for enhancing SOC sequestration. It is essential for stakeholders to increase cropland SOC sequestration efficiently.
Highlights:
- IPCC tier 3 approach was applied to quantify cropland SOC sequestration potential
- 20 % increase in C input would not be enough to meet the 4 ‰ target over 2021-2040
- Climate change would reduce SOC sequestration on average by 0.28 t C ha-1yr-1
- Contribution of C input, temperature, precipitation to SOC sequestration is 56%, 24%, and 20%
Reference
Fulu Tao, Taru Palosuo, Aleksi Lehtonen, Jaakko Heikkinen, Raisa Mäkipää. 2023. Soil organic carbon sequestration potential for croplands in Finland over 2021–2040 under the interactive impacts of climate change and agricultural management, Agricultural Systems, 209, 103671.