Soil - WRB groups

Definition: Thematic map layer in the soil dataset providing the dominating WRB-group for each soil polygon in accordance with the World Reference Base for Soil Resources (WRB) 1989. The Norwegian Soil survey is a systematic survey of soils on agricultural areas in mainland Norway. Data is collected by fieldwork which includes mapping the distribution of soil types by interpreting aerial photographs and verification and identification of soil types in the field using a soil auger. The boundaries between areas with different soil types are digitized in a GIS on site. Soil types are defined on the basis of major soil properties. The World Reference Base of Soil Resources (WRB) is linked as our national classification system, and is used as basis for our soil mapping units. A soil feature in the soil database is a continuous area with the same attributes assigned according to the classification criteria of soil types with a geometric representation as a polygon. Soil maps describes agricultural areal according to a national standardized classification systems of soil and other local attributes such as slope. Around 55 % of the country’s agricultural land has been mapped so far. As the soil survey will in foreseeable future only have partial national coverage, an area frame survey has been implemented in order to provide national and regional soil statistics. Plots of 0,9 km2 has been established in a 9 x 9 km grid across Norway, and all agricultural areas on these plots are classified and mapped for soil properties using the same approach as in the ordinary soil survey. The result is a representative sample used to provide estimates of soil types and properties at the national and regional level.