SaltMod estimation of root-zone salinity Varadarajan and Purandara Application of SaltMod to estimate root-zone salinity in a command area

Abstract Waterlogging and salinity are the common features associated with many of the irrigation commands of surface water projects. This study aims to estimate the root zone salinity of the left and right bank canal commands of Ghataprabha irrigation command, Karnataka, India. The hydro-salinity model SaltMod was applied to selected agriculture plots at Gokak, Mudhol, Biligi and Bagalkot taluks for the prediction of root-zone salinity and leaching efficiency. The model simulated the soil-profile salinity for 20 years with and without subsurface drainage. The salinity level shows a decline with an increase of leaching efficiency. The leaching efficiency of 0.2 shows the best match with the actual efficiency under adequate drainage conditions. The model shows a steady increase, reaching the levels up to 8.0 decisiemens/metre (dS/m) to 10.6 dS/m at the end of the 20-year period under no drainage. If suitable drainage system is not provided, the area will further get salinised, thus making the land uncultivable. We conclude from the present study that it is necessary to provide proper drainage facilities to control the salinity levels in the study area.