Natural Resource Management in NSW

Soil Survey Standard Test Methods

The Department's Wellington laboratory has prepared instructions on sample preparation and 24 standard physical and chemical test methods for the use of soil surveyors and anyone else interested in interpreting or performing soil tests. The tests are reasonably simple and aim to ensure that accurate and consistent methods are used when conducting laboratory tests for soil survey. Most tests do not require expensive, sophisticated equipment or extensive resources. They can be performed in laboratories that have basic glassware, clean water, a drying oven and a top loading balance. Few tests are difficult, labour-intensive, tedious or time-consuming.

Preference is given towards more samples and more tests of lower precision to determine prevailing conditions over broad areas rather than fewer tests of higher precision. The work is used to characterise and screen large areas. For site-specific high precision results, more painstaking methods may be required.

This suite of tests is designed to provide information on a wide range of soil attributes, which can then be used to determine capability for specific land uses and to guide land management.

Most tests are performed on all samples, but some tests such as the Emerson Aggregate (P9B/2) and the Non-Wind Erodible Aggregates (P21A/1) tests require coherent samples. Other test methods such as Linear Shrinkage (P6A/1) are performed only on dispersible soils because dispersion can mask the shrink-swell response in Volume Expansion (P5A/1) (see Mills, JJ, Murphy, BW & Wickham, HG 1980, 'A study of three simple tests for the prediction of soil shrink-swell behaviour', Journal of the Soil Conservation Service of NSW 36: 77-82). The Citrate-Dithionite Extractable Iron test method (C15A/1) is only performed on subsoils suspected of being Ferrosols, so it is necessary to confirm Ferrosol classification (see Isbell, RF 1996, The Australian Soil Classification, CSIRO Publishing, Melbourne).

The tests are based on Soil Testing Procedures by B Craze, G Holman, GA Chapman and MJ Stone (Department of Conservation & Land Management, unpublished 1992) and can be used with Soil Landscape Reports and Maps. Where possible, the chemical test methods are equivalent to Rayment & Higginson’s Australian Laboratory Handbook of Soil and Water Chemical Methods (1992) .