Emissions from Organic Soils

Subsidence of a drained organic soil used for arable crops

Switzerland’s organic soils have already lost a large part of their peat owing to historic land use, but still store around 32 million tonnes of carbon. Nevertheless, organic soils used for agriculture are steadily losing carbon – about 600,000 tonnes CO2 equivalent per year.

Old peat-cutting sites and drained organic soils in Bannriet, canton of Sankt Gallen.

Carbon losses (mainly oxidative losses as CO2) are due to drainage of the land in question for forestry and agriculture. Since 1850, carbon losses from organic soils in Switzerland have been considerable: by contrast, carbon losses due to peat extraction over the same period were low. The latter half of the 20th century in particular saw a rise in emissions despite the ban on peat extraction, because of the intensified farming of organic soils.

Measuring CO2 and methane fluxes on peatlands in Switzerland’s Seeland region

Large expanses of intensively used agricultural land with organic soils are located in flat, wide valley floors, e.g. in Switzerland’s Seeland region. Here, over two years, Agroscope specialists determined the carbon loss of an agriculturally-used former fen using a micrometeorological method, with a view to improving the emission factors used in the Swiss Greenhouse Gas Inventory.

Agroscope is currently studying two options for reducing the greenhouse-gas emissions of agriculturally-used organic soils: mineral soil coverage and wet rice cultivation.