DOI: 10.25919/5f1632a855c17
title: Atlas of Australian Soils (digital)

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.