Peatlands : Sustainable management of organic soils

Organic soils or peatlands are suitable for agriculture or forestry only after intensive drainage. Drainage triggers fast mineralisation of carbon that has been sequestered for millennia. Drainage of organic soils is responsible for an equivalent of 14 per cent of annual greenhouse gas emissions from agricultural soil loss and subsidence. Although there is an awareness of this fundamental problem, these soils are not targeted by specific management regulations.

The aim of the project was to establish which characteristics of organic soils are the main causes of mineralisation and to identify policy instruments effective in promoting a more sustainable management of the remaining peat soils.

There is no sustainable, economically promising way of managing organic soils in an intensive way and of conserving the carbon store at the same time. Extensively managed organic soils contain more labile carbon and bear a huge emission potential with intensification. Land management is no major factor for the degree of soil degradation. Plant litter application aimed at reducing the mineralisation of peatlands and carbon accumulated from Miscanthus (a bioenergy plant) cultivation cannot compensate for peat carbon loss.

Indicators for assessing the impact of agricultural production on peatlands were developed for three levels (plot, farm, regional). Farmers’ decisions were simulated under alternative agri‐environmental payment schemes. The tested payment schemes incentivise cooperation between farmers towards a more extensive use.

• Peat composition must be considered when assessing the future emission of an organic soil. The classical von Post method to define peat humification on site delivers promising results in this context.
• Recent plant residues accumulating over years in soil are more labile than the peat itself.
• Indicators for the analysis and comparison of different agricultural production systems were developed.
• Peat soil management from an agricultural and economic perspective were analysed.
• The question of an optimal design of “agglomeration payments” was addressed in a framed and dynamic experiment.

Less degraded peatlands exhibit the biggest CO2 emission potential when drained. Hence previously established protection measures have to be maintained or fortified. All intensive forms of land‐use currently practiced in Switzerland degrade the peat, including Miscanthus cultivation. By addressing indicators for the agricultural use of peatlands and how different management practices perform, the project provides means for a comprehensive assessment of potential future targets regarding peatland use and conservation. By capturing the need for cooperation between farmers and variability of farmers’ opportunity costs for changing soil management, the project team identifies policy instruments to foster a change in soil management. The calibration of the experiment with actual economic data enables an estimation of the implementation costs of such policy instruments.

Sustainable Management of Organic Soils