The 2024 estimate of Switzerland’s organic soil surface is an update of the 2015 estimate of organic soils. As in the 2015 map, it used the approach of collating existing information sources (e.g., soil maps, geology maps, forest habitat maps, historical observations of peatlands, as well as inventories of fens and raised bogs) to generate an estimate or the current extent of organic soils. In a first and important step, four important data sets were updated: Soil maps, geology maps, the national inventory of raised and transitional bogs, and the forest habitat maps. This update encompasses approximately ten years of newly available data. In a second step, all data sets were harmonized and inserted into a data model, allowing the semi-automatic combination of the various data sets. In a third step, the data sets were combined (more specifically, overlain) and a rule-based method was used to characterise the resulting surfaces as organic soil, or not organic soil. In a fourth step, information on the mineral soil surface was used to delete surfaces for which the evidence of mineral soil was stronger. The soil surface recommended for use in most applications is 32,702 ha, which corresponds to the ‘less conservative’ estimate of organic soils. Because of the heterogeneous nature of the information sources that were used to generate this indicator map, it is not possible to define the scale for which this map is appropriate. The following recommendation can however be made: The map is suitable for use at the regional scale (e.g., cantonal or district, ca. 1:100,000) and larger scale only; it is unsuitable for field-scale use. The two publications (Wüst-Galley, C. and J. Leifeld (2025) “The distribution and (future) use of Switzerland’s organic soils” Mires and Peat 32(4): 1-17, DOI: 10.19189/001c.130819 and Wüst-Galley, C., A. Grünig and J. Leifeld (2015) “Locating organic soils for the greenhouse gas inventory” Agroscope Science 26, 100 pp.) describe the methodology and updated data sets in detail, and it is strongly recommended that both publications should be read by anybody wanting to use this data set.
