Level Up

Appendix 1

Use of codes in recording classification of soil profiles

Confidence level of classification

In a number of instances it will not be possible to fully classify the soil because of a lack of laboratory data. It is desirable to indicate the level of confidence when any attempt at classification is made.
  1. All necessary analytical and/or morphological data are available.
  2. Analytical data are incomplete but are sufficient to classify the soil with a reasonable degree of confidence, e.g. free iron oxide data may be lacking but it is known that the soil is formed from basalt.
  3. No necessary analytical data are available but confidence is fair, based on a knowledge of similar soils in similar environments, e.g. presence of columnar structure is normally a reliable indicator of sodic soils.
  4. No necessary analytical data are available and the classifier has little knowledge or experience with this kind of soil, hence the classification is provisional.

Examples of a coded classification of a soil profile

The codes presented in these examples are listed in the following order:
Confidence level; Order; Suborder: Great group: Subgroup; Family criteria 1-5

This ordering is not prescriptive and the manner in which the classification is recorded on field data sheets is an operational matter. However, the national standard soil profile data base design, developed by the Australian Collaborative Land Evaluation Program (ACLEP), specifies that the coding system outlined in this classification is to be used for data exchange.

Example 1

1 CH AA AH AT A F L O T
This would decode as Bleached, Eutrophic, Red Chromosol; thin, slightly gravelly, loamy / clayey, very shallow. (Confidence level 1).

Example 2

If a level within the classification hierarchy is indeterminable from the available information this should be coded as [YY]:
4 KA AA YY BU
Ferric, ?, Red Kandosol (Confidence level 4).
where YY is defined as: Class undetermined.

Example 3

If there is no available class this should be coded as [ZZ]:
1 RU AO ZZ AR
Basic, n/a, Arenic Rudosol (Confidence 1evel 1)
where ZZ is defined as: No available class

Example 4

If only a subset of the family criteria has been recorded then this should be coded as follows:
1 TE IN EA AI A - K K -
Acidic, Petroferric, Red-Orthic Tenosol; thin, -, sandy / sandy, -, (Confidence level 1).
where - is defined as: Not recorded

In this example it is important to note that family criteria with a code of ‘K’ is valid for ‘A1 horizon texture’ and ‘B horizon maximum texture’. Recording of all the family criteria is essential. In order to avoid any future confusion or ambiguity, it is essential to record the family criteria in the same order as they are presented in the publication.