Brief description
The Atlas of Australian Soils (Northcote et al, 1960-68) was compiled by CSIRO in the 1960's to provide a consistent national description of Australia's soils. It comprises a series of ten maps and associated explanatory notes, compiled by K.H. Northcote and others. The maps are published at a scale of 1:2,000,000, but the original compilation was at scales from 1:250,000 to 1:500,000.Mapped units in the Atlas are soil landscapes, usually comprising a number of soil types. The explanatory notes include descriptions of soils landscapes and component soils. Soil classification for the Atlas is based on the Factual Key.
The Factual Key (Northcote 1979) was the most widely used soil classification scheme prior to the Australian Soil Classification (Isbell 2002). It dates from 1960 and was essentially based on a set of about 500 profiles largely from south-eastern Australia. It is an hierarchical scheme with 5 levels, the most detailed of which is the principal profile form (PPF). Most of the keying attributes are physical soil characteristics, and can be determined in the field.
A number of map unit interpretations have been developed to assist with national perspectives on soil information. They are also available for download.
1. Interpretations of soil properties based on the dominant Northcote classification (1992): The first set of interpretations of soil properties for the dominant soil of each landscape. Soil permeability, water holding capacity, texture, reaction trend, nutrient response and depth characteristics are assigned to relative classes. Report and many caveats are included.
2. Australian Soil Classification conversion (1996): A table that converts the Atlas of Australian Soils mapping units to an Australian Soil Classification soil Order was compiled to aid the production of Concepts and rationale of the Australian Soil Classification. Caveats and colours included.
3. Estimations of soil properties based on the dominant Northcote classification: McKenzie et al (2000) compiled tables estimating typical ranges for soil properties associated with each principal profile form (PPF) of the Factual Key. These tables were intended for use with the Atlas of Australian Soils, to provide estimates of specific soil properties for each map-unit.
Interpretations for each soil type were based on the range observed in approximately 7000 soil profiles held within the CSIRO National Soil Database, with ancillary data from Northcote et al. (1975). The systematic structure of the Factual Key makes interpolation between soil classes relatively straightforward. Soil properties were estimated using a simple two-layer model of the soil consisting of an A and B horizon. The following properties have been estimated for both the A and B horizon: horizon thickness, texture, clay content, bulk density, grade of pedality and saturated hydraulic conductivity. The estimates of thickness, texture, bulk density and pedality have been used to estimate parameters that describe the soil water retention curve - these allow calculation of the available water capacity for each layer. Interpretations relating to the complete soil profile are presence or absence of calcrete and gross nutrient status.
Caveats on the use of these interpretative tables to predict soil properties spatially are discussed by McKenzie et al (2000). A very large proportion of soil variation within a region occurs over short distances and cannot be resolved by reconnaissance scale maps. The qualitative nature of the Atlas and restrictions associated with the classification scheme and structure of the soil-landscape model impose further constraints. Technical reported included.
Lineage
In 1991, a digital version of the Atlas was created by the Bureau of Rural Science from scanned tracings of the published hardcopy maps. The Digital Atlas of Australian Soils is available as a shapefile. Additionally, there is a reliability map available, with a descriptive legend. The source of the reliability data is unknown.The Digital version of the Atlas of Australian Soils was constructed from scanned tracings of the published hardcopy source maps, the thirteen sheets of the Atlas of Australian Soils. Use of the hard copies was necessary as the original printer's separates could not be located. The positional errors inherent in the original source maps would have been added and errors introduced by subsequent processes, beginning with the natural process of paper stretch. This was followed by the data processing steps which were, in order of execution: tracing, manual digitizing, transformation of coordinates and rubber sheeting to edge-match the digital versions of the adjacent sheets.
Interpretations of the mapping units have led to the development of look-up tables for the atlas. It is important to note the many caveats are attached to these. Tables are supplied as ascii, comma delimited. Care must be taken when joining/linking the tables to the data, due to the use of mixed case in mapping unit codes.
Data time period: 1960-01-01 to 1991-01-01
Subjects
Environmental Sciences |
Soil Sciences |
Soil Australia Northcote Atlas |
Soil Sciences Not Elsewhere Classified |
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Identifiers
- Local : 102.100.100/264762
- DOI : 10.25919/5f1632a855c17
