Remote sensing-based assessment of waterlogging and soil salinity: A case study from Kerala, India

Waterlogging and raised soil salinity are leading to land degradation and desertification problems worldwide. It can significantly reduce the agricultural practices and crop yields of affected lands. The present study is attempted to map waterlogged and saline affected areas using LISS-III satellite imagery of pre-monsoon and post-monsoon season of the year 2012. It was observed that the total size of seasonal waterlogged (only Rabi or only Kharif) is 454.96 ha (2.37%) of the total area. The land covered with perennial waterlogged area was found to be 535.54 ha (2.79 %) of the entire command area. The waterlogged area concerning the depth of groundwater was further categorized into most critical, critical, less critical and non-critical. The identification and mapping of salt affected (saline) area was performed during Rabi and Kharif season. Only 0.46% of the command area identified as saline land either in both or single season patches, remaining 99.54% area comes under non saline category. Out of total command area 80.58 and 19.42% areas comes under non-saline and saline zones respectively. The saline area was further classified into medium, high and very high zones. The saline affected area covered with medium, high and very high salt categories is 2.25 ha (0.012%), 26.380 ha (0.137%), and 0.624 ha (0.003%), respectively. In-situ measurements such as pH, electrical conductivity (EC) and exchangeable sodium percentage (ESP) were also used to validate the results. The methodology proposed in this study can potentially be used for cost-effective mapping of soil salinity in other geographical regions.