Salt-affected soils have undermined the effectiveness of agricultural development of considerable areas of the world, especially in the arid and semi-arid regions. This research is set out for the direct measurement of salt-affected soil. Two experiments were conducted to study the influence of different salt types and concentrations on spectral reflectance of soil. In the first experiment, five different salts (Na₂SO₄, NaHCO₃, CaCO₃, CaCl₂ and NaCl) were mixed individually with Gila soil at 0.51, 1.51 and 3.0% by weight. The second experiment was conducted to examine the spectral response of sodium sulfate and sodium bicarbonate (individually and in combination) in Gila soil at 3.0 and 6.0% by weight. Reflectance measurements were made over all soil treatments under different moisture conditions. Upon drying (24-hour after wetting), different salt types and concentrations showed different spectral response. The chemical analysis of soil samples have indicated some important relationships which influenced, directly and indirectly, the spectral reflectance of soil surfaces.

Bibliography: leaves 119-218. / xiv, 218 leaves : ill. (some col.), maps (some col.) ; 30 cm. / Title page, contents and abstract only. The complete thesis in print form is available from the University Library. / Salt Manager represents the software system developed by this thesis to implement an interactive land classification methodology. An Expert System (ES), a Geographic Information System (GIS), remotely sensed information and a relational database management system (RDBMS) have been utilised to construct the methodology. / Thesis (Ph.D.)--University of Adelaide, Dept. of Geography, 1995