Soils play an important role in the carbon cycle. The total carbon content in the soil (1500 Gton) is twice as large as the amount of carbon in the atmosphere. Much of this carbon is stored in peat soils. Small changes in this stock can therefore have a big influence on the emissions of CO2.
Of the total carbon emissions, about half end up in the atmosphere. The other half is absorbed in euqal measure by oceans and forests, each accounting for 2.6 Gton CO2. CO2 storage is not limited to trees, it is also – and can be even more so - captured in agricultural and forestry soils.
Carbon sequestration in the soil
It is possible to capture carbon in the soil. Dutch agricultural land could theoretically sequestrate 5 Mton CO2 per year by making use of different methods, such as:
- Ploughing little
- Reintroducing crop residues in the soil
- Administrating manure and/ or compost
- Making use of suitable crop rotation schemes
Costs and agricultural constraints, however, cause the realistic potential to be much lower: 1Mton CO2 per year. This corresponds to 40% of the overall carbon sequestration of Dutch forests. Avoiding emissions from peat lands in the Netherlands - now over 4Mton CO2 per year - may very well have a higher climate mitigation potential. However, this requires (major) changes in the management of the peatland areas.
In addition to the role of soils in climate change mitigation through carbon sequestration, the soil also plays an important role in climate change adaptation. Soils are vulnerable to climate change: for example salinization of soils caused by less rainfall, increased risk of erosion by heavier rainfall and water shortage by longer periods of drought. A more climate resilient soil can provide a better water retention capacity and higher yield, a larger role in (surface) water management focused on retention and disposal, and has an improved soil structure and soil life and thus soil fertility.