Soil Science

Soil Classification

Soils are difficult to classify because they do not form more-or-less distinct entities like plant and animal species do, for example. Throughout the world, many general soil classification schemes have been developed, and in Australia, there are three. It is not possible to give a full description of each scheme here.

To use them to classify a soil profile, you should consult the source documentation.

Great Soil Groups

There are 43 great soil groups in this scheme. The soil profile is matched to one of the great soil groups based on its morphology (i.e., its appearance and properties) and on inferences as to how it was formed (e.g., the extent to which the profile has been leached). Examples of great soil groups are black earths, red podzolics, kastanozems, and red-brown earths.


Northcote's Factual Key

Northcote (1979) developed a key with which to classify soils entirely based on profile morphology. No interpretation of genesis is required. The final stage of the key fits a soil profile into one of 855 "principal profile forms", which are designated by a letter-number code (e.g., Dr4.21). In the past, it has been widely used in Australian soil mapping projects but is now being superseded by the Australian Soil Classification.


The Australian Soil Classification

This soil classification scheme is newer than the other two. Soils are classified using a key primarily based on profile morphology and use the terminology from McDonald et al. (1990). The initial division is into one of 14 soil orders.

 

 

 

 

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