Use of Landsat Imagery and Aerial Photographs for Delineation and Categorization of Salt-Affected Soils of Part of North-West India

Salt-affected soils in a part of north-west India have been studied using multispectral and multitemporal landsat data and aerial photographs. Different categories of such soils, based on the areal extent of the hazard, could be delineated on the landsat imagery (LI). Enlargements of landsat imagery from 1:1 m to 1:250,000 provided extra delineation of units but further enlargement to 1:120,000 scale did not prove to be of advantage. The approach for the interpretation of LI and air photos was same up to subland type, there fter a different approach had to be adopted for subdividing these units. A good coincidence was found in the boundaries of landsat imagery and air photo-interpretation maps. The LI interpretation units have also been correlated with air photo-interpretation units. Landsat data were useful for mapping at 1:250,000 scale or smaller.