Australian Soils with Saline and Sodic Properties

Twenty-seven classes of based on defined chemical criteria for salinity, sodicity, and alkalinity were established, and in the context of this study 25 of these are regarded as salt-affected soil classes. Classification of about 1500 soil profiles of known morphology demonstrated that about 12 classes accomodated most of these profiles. A study of the relation between the morphology of these profiles as principal profile forms of the factural key for recognition of Australian soils and the salt-affected soil classes resulted in six broad categories of morphologic soil groupings, each with distinctive assemblages of the salt-affected soil classes. From these morphologic groupings and their salt-affected soil classes six broad mapping units were defined: SS, Saline Soils; AS1, Alkaline Strongly Sodic To Sodic Clay Soils; AS2, Alkaline Strongly Sodic to Sodic Coarse-To Medium- Textured soils; AS3, Alkaline Strongly Sodic to Sodic Duplex Soils; NS1, Non-Alkaline Sodic to Strongly Sodic Neutral Duplex Soils; NS2, Non-Alkaline Sodic to Strongly Sodic Acid Duplex Soils. The distribution of these six map units has been shown on the accompanying tentative map of Australian with saline and sodic properties by using those map units delineated on the Atlas of Australian Soils which are dominated by with morphologies associated with the salt-affected soil classes. The agricultural land use of these units is briefly reviewed and discussed, as is the question of secondary salinization. /A/