Soil polygons classified according to soil quality into three classes (1 Very good; 2 Good; 3 Less good). The classification is based on considerations of soil attributes important for the agronomical use and slope. The classification has not considered climate and assume that the soil has been subject to appropriate agronomical practices. The classification scheme is adapted to use in land use planning.

The Norwegian Soil survey is a systematic survey of the soils on agricultural areas. 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 quality feature in the soil database is a continuous area with the same attributes assigned according to the classification criteria of soil quality with a geometric representation as a polygon. Soil quality is derived from information in the soil database.

Agricultural soil quality combines soil resource classes based on the limitations for agricultural use and terrain properties such as slope, and it divides the agricultural areas into three classes, high, medium and low soil quality.

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.