Soil Moisture Maps

Last changed: 10 November 2023
Soil moisture map

The SLU Soil Moisture Map is a high-resolution map that shows soil moisture on a scale from 0 to 100, where low values indicate dry soil and high values indicate wet soil. The colours on the map "blend together" to illustrate smooth transitions. On the SLU Soil Moisture Map, red areas indicate dry soil, yellow areas mesic soil, green areas mesic-moist soil, turquoise areas moist soil and blue areas wet soil.

The color shades reflect more the natural variations in the landscape where there are rarely sharp boundaries between different soil moisture classes. The color shades also provide the opportunity to interpret seasonal variations in the map.

The classified SLU Soil moisture map is a high-resolution map that shows soil moisture in three classes; wet - moist, moist - mesic and mesic - dry. If you want to use a classifed map instead of the continuous one, this is the one we recommend. Reclassifying the continuous map does not give as good results.

The soil moisture maps are calculated with artificial intelligence. By combining the information in many different map layers as input into the model and training the model on field data from the national forest inventory, the model learns how topography, climate and soil types control soil moisture in different parts of the country. For those who want to understand the calculations in depth, we refer to the research article.

SLU Soil moisture map was primarily developed for use in forest planning, but can also have other uses. How dry or wet an area is at a certain time depends on how the weather has been. On the SLU Soil Moisture Map, blue and turquoise areas show where the soil can be expected to be wet and moist for most of the year. Green areas show mesic-moist soil where soil moisture can be expected to change more. On such ground you can walk dry footed with shoes in summer, but not after heavy rains or after snowmelt. The green-marked areas risk being connected to nearby watercourses when the runoff is high. In order to protect surface waters, one should therefore be extra careful in both blue and green marked areas on the SLU Soil Moisture Map by, for example, avoiding fertilization, soil preparation and rutting. The SLU soil moisture map also provides information on soil moisture in drier areas. For forestry planning, this information can be useful, for example, when planning roads.

Anyone has the right to download and use the SLU Soil Moisture Map.

 

The maps are found HERE

For publication, state the source: SLU Soil moisture map, Dept. of Forest Ecology and Management, Swedish University of Agricultural Sciences. 

The method-development for the map is described in Ågren, A. M., J. Larson, S. S. Paul, H. Laudon, and W. Lidberg (2021) Use of multiple LIDAR-derived digital terrain indices and machine learning for high-resolution national-scale soil moisture mapping of the Swedish forest landscape. Geoderma, 404, 115280, https://doi.org/10.1016/j.geoderma.2021.115280

Facts:

  • The SLU Soil Moisture Map consists of information with a high degree of detail over most of Sweden's forest land.
  • The basic format is raster data with a resolution of 2×2 meters in the SWEREF99TM projection.
  • The classified SLU Soil moisture map contains information on soil moisture in three classes; wet - moist, moist - mesic and mesic - dry.
  • The map is produced for the entire landscape, but as the map is trained on data from forest land, it means that the results cannot be assessed for quality on land other than forest land.
  • The maps that form the basis of the calculations come from Lantmäteriet, SGU and SMHI.
  • By processing the national elevation model (NNH), SLU has developed a series of variables that can model soil moisture. The map is produced by combining the information from many maps with the help of artificial intelligence (AI).
  • The AI model learns how topography, climate and soil types control soil moisture in different parts of the country.

Contact

Kontaktinformation

Anneli Ågren 
Forskare vid Institutionen för skogens ekologi och skötsel; Akvatisk landskapsanlays
Telefon: +46907868365, +46727144792
E-post: anneli.agren@slu.se