Mapping of soil salinity and sodicity using digital image analysis and GIS in irrigated lands of the Indo-Gangetic Plain

Salt-affected soils in irrigation command of the Western Jamuna Canal were mapped using digital image analysis and GIS. Landsat TM data were assigned sample strip derived training sets for supervised classification using ILWIS software. The final map showed five salinity classes with an over all accuracy leyel of 85.6 per cent. Moderate and highly saline areas were easier to identify than the slightly saline areas. Combination of red and infrared bands was used for separating saline and sodic soils. A GIS overlay of spatial information was developed to generate base map. Additionally, the non-spatial information such as soil characteristics and salinity parameters were incorporated suitably into the information files as point information to integrate with remotely sensed data. Geo-referenced, digitized, spatial and point data sets were linked to rasterised map. Thus relating of salinity classes to topology and environmental attributes enhanced the use of database in salinity management of irrigated agriculture.