Landsat imagery for mapping saline soils and wet lands in north-west India

Soil salinity and waterlogging are two of the main soil limitations of irrigated agricultural lands. Full use of these resources requires up-to-date data on their areal extent and geographic distribution. This paper uses Landsat MSS data in imagery form of 1:250 000 scale for these purposes. The study area, forming a part of the Indo-Gangetic alluvial plain, is located in the Mathura district of Uttar Pradesh, India. Large-scale seepage from canals and irrigation channels and obstruction in natural drainage have caused waterlogging and salinity hazards. A collative approach comprising the use of Landsat imagery, Survey of India topomaps and limited field checks was followed for mapping purposes. The wet land soils appeared in bluish tones whereas both the saline and sandy soils appeared in white tones on the false colour composite imagery. Distinction between saline and sandy soils was made after carefully studying the unique patterns of shape and geomorphic setting. The study area covers 381 100 ha, out of which 14 035 ha are saline soils and 14 355 ha are waterlogged soils. Two maps showing areas under soil salinity and wet lands were also made.