Emissions from Organic Soils

Measurement of CO2 and methane flows on peatlands in Switzerland’s Seeland region

Despite their previous use, around 30 million tonnes of carbon are still stored in organic soils. However, these soils are continually losing carbon – around 600,000 tonnes CO2-equivalent per annum in the case of those used for agriculture. Larger areas of agriculturally intensively used organic soils are found in flat, broad valley floors such as Switzerland’s Seeland region. Here, we quantified the carbon loss of a highly degraded, agriculturally managed former fen over a two-year period by means of micrometeorological methods. Further details can be found here: 
ScienceDirect: Carbon budget response of an agriculturally used fen to different soil moisture conditions.

Since 2018, at a site in the St. Gallen Rhine Valley, we have been studying whether carbon loss in organic soils can be reduced – in spite of agricultural use – by ‘cover-sanding’ with mineral soil material. For this, CO2, methane and nitrous oxide greenhouse-gas exchange is being measured continuously over a period of several years. Using isotopes (14C), we can analyse the origin of the emitted  COand thus check whether the mineral cover protects the underlying peat from decomposition. Further details can be found here:
ScienceDirect: Soil carbon loss from drained agricultural peatland after coverage with mineral soil

The influence of mineral cover-sanding on the nitrogen cycle is being traced using isotopes (15N). Our measurements from both sites will be included in the Swiss Greenhouse Gas Inventory.

Measurement of CO2, methane and nitrous oxide flows on cover-sanded organic soils

In addition to measuring the current emissions, we estimated the historic emissions of Switzerland’s organic soils since the early 18th century : 
Land use-driven historical soil carbon losses in Swiss peatlands.

The cumulative oxidative losses of carbon (mainly as CO2) from organic soils in Switzerland are considerable. Compared to these, carbon losses over the same period from peat extraction are low. In the second half of the 20th century in particular, emissions rose – despite the ban on peat extraction – owing to the intensified management of organic soils. 

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