Scoping study to identify current soil organic carbon stocks and the potential for increasing carbon sequestration in Scottish soils
Read the full reportThe report estimates that Scottish soils hold around 3,000 Mt of organic carbon, with the highest concentrations in uplands and the lowest in arable lands. While there is potential to store an additional 148 Mt of carbon in grassland and arable topsoils, there is also a risk of losing up to 112 Mt. The only significant increase in soil organic carbon over time was observed in woodland soils.
This report evaluates the status of organic carbon in Scottish soils, including its distribution, changes over time, and potential for gain or loss.
The total stock of soil organic carbon to 100 cm depth in Scottish soils is estimated to be around 3000 Mt C.
Soil carbon distribution is highest in uplands and lowest in eastern lowlands.
Cultivated land, especially arable land has the least soil organic carbon. Soil carbon concentrations are higher in rotational grassland, and highest in permanent grassland and upland soils.
There is potential to store an additional 60 Mt C in grassland topsoils and 88 Mt C in arable land topsoils, but also a risk of losing up to 112 Mt C.
The only significant increase in SOC stocks over time was observed in woodland soils.
Recommendations for policy implementation
- Suggested methods to increase SOC include reduced or no tillage, increased residue returns, fertilising, liming, organic manures, growing catch crops, crop rotation, and changes in grazing intensity.
- Implement consistent protocols for sampling and monitoring SOC to assess changes over time accurately.
- Incorporate SOC improvement methods into broader agricultural and environmental policies to maximise co-benefits, such as improved soil structure and water retention.