Soil Classification

The importance of soil classification

Soil classification concerns the grouping of soils with a similar range of properties (chemical, physical and biological) into units that can be geo-referenced and mapped.

Soils are a complex natural resource, much more so than air and water. They contain all naturally occurring chemical elements simultaneously in solid, liquid and gaseous states. Soils are ‘dirty’ systems.

The number of physical, chemical and biological characteristics and their combinations in soils are nearly endless. It’s no wonder then that many different approaches have been proposed to grouping soils. Soil classification systems are specially designed to cope with the landscapes and soils they intercept. Australia, with its large areas of very old soils, uses the Australian Soil Classification. This classification system uses diagnostic horizons and soil features to group and separate soils.

Soil classification systems have also been developed for different purposes:

  • Soil Taxonomy: soil survey interpretation
  • The FAO Legend: global distribution and geography of soils
  • WRB: correlates different soil classification systems;

In Australia the National Committee on Soil and Terrain (NCST) is the peak government committee providing national leadership and coordination on the assessment of soil and terrain in Australia.