Soil Sodicity in Victoria: an Overview | The Assessment of Soil Sodicity | Role of Sodicity in the Australian Soil Classification |
The sodic (i.e. Na-affected) character of soils has been the subject of a large volume of research both in Australia and around the world. A decision to map the global distribution of salt-affected soils at a scale of 1: 5 000 000 was made at an international meeting in Budapest in October 1967 and the paper entitled `Australian soils with saline and sodic properties' was the Australian contribution to the task (Northcote and Skene, 1972). This influential research formed the basis of sodic soil maps used in the `First National Conference and Workshop on Sodic Soils' conducted in Adelaide during 9-13 November 1992 (Naidu, 1993), the entire proceedings of which were published in the book entitled `Australian sodic soils: distribution, properties and management' (Naidu et al., 1995). Soil sodicity was an important factor in the Australian Soil Classification (Isbell, 1995; 1996). Further work on the subject was presented in the textbook edited by Sumner and Naidu (1998). Recently, an international conference on soil sodicity as it related to various agricultural industries was held in Tatura from 28 February to 1 March 2000 (Surapaneni, 2001) and some of the proceedings were published in the Australian Journal of Soil Research 39, 6 (2001) and the Australian Journal of Experimental Agriculture 42, 3 (2002). |
A Grey Sodosol near Chiltern. Note the presence of a bleached subsurface (A2) horizon overlying a dense and coarsely structured sodic clay subsoil - which significantly restricts root and water movement. Photograph: Mark Imhof. | |
The following two brochures were published by the Cooperative Research Centre for Soil and Land Management (Adelaide) and focus on the issue of soil sodicity/sodic soils and its/their associated problems. Permission to reproduce these brochures has been granted by the senior author, Dr P. Rengasamy. | |
Introduction to Soil Sodicity (P. Rengasamy and L. Walters) Relations between soil sodicity, salinity and soil structure are briefly outlined in this brochure. Particular emphasis has been placed on the origins, manifestations and reclamation of affected soils. Introduction to Soil Sodicity | |
Managing Sodic, Acidic and Saline Soils (P. Rengasamy and J. Bourne) Large areas of the Australian continent are affected by soil sodicity, salinity and acidity. The information contained in this brochure comprises a description of a field test to diagnose each of the above-mentioned problems as well as broad measures for remediation. Managing Sodic, Acid and Saline Soils prt 1 Managing Sodic, Acid and Saline Soils prt 2 Managing Sodic, Acid and Saline Soils prt 3 Managing Sodic, Acid and Saline Soils Appendix To view the information PDF requires the use of a PDF reader. This can be installed for free from the Adobe website (external link). |
Major Sodic Soil Classes of Victoria at a scale of 1: 2 000 000 (Ford et al. 1993). © CSIRO Reproduced with permission of CSIRO PUBLISHING. http://www.publish.csiro.au/journals/ajsr/ | Using the scheme presented by Rengasamy and Olsson (1991), which related sodicity to soil pH, Ford et al. (1993) noted that alkaline sodic soils covered 37.0 % of the State and were located in the Murray Basin and west Victorian volcanic plains. Neutral sodic soils occurred in the plains to the south and west of the State and occupied 10.0 % of the land area, whilst those in the acidic sodic class were found in the central uplands and on the south coast and comprised 12.0 % of Victoria. The following map was based on an enlarged and simplified of the map produced by Northcote and Skene (1972) (see map above) and adjusted according to the classes proposed by Rengasamy and Olsson (1991). Saline sodic soils were not mapped owing to a lack of suitable data (Ford et al. 1993). |
Dominant Soils of Victoria which relate to Sodic Soil Classes at a scale of 1: 2 000 000 (Ford et al. 1993). © CSIRO Reproduced with permission of CSIRO PUBLISHING. http://www.publish.csiro.au/journals/ajsr/ | The map of dominant soils as they were related to sodicity was a much simplified version of the Northcote Soil Map of Victoria in which 25 class units were reduced to 12. According to the scheme of Northcote (1979), the alkaline soils comprised red and yellow duplex soils, calcareous earths and self-mulching cracking clays whilst the neutral and acidic soil classes were predominantly yellow duplex types. A large area of red duplex soils marked to the northwest of Horsham as non-sodic has been recently reassessed as sodic by M. Imhof (pers. comm.). |