Leaching of a Sodic Water Deteriorated Salty Soil

Desalinisation and desodification leaching curves were constructed on a sandy loam, saline sodic soil, using canal and poor quality (EC 1.4 mmhos/cm, SAR 14, RSC 4.2) waters. Excess neutral salts and high SAR in the soil had resulted due to prolonged irrigation with sodic water and poor drainage conditions. Empirical equations of the type Y=aX^−b were fitted to the experimental leaching curve data. It was found that 1 and 1.4 units of good and poor quality waters per unit depth of soil, respectively were required to be passed through soil for removal of 80% of the salts. In this soil, desalinisation was not entirely accompanied by desodification. Gypsum application was therefore, necessary for controlling SAR and for checking the alkalinity development as well as reduction in infiltration rate. Relatively higher infiltration rate was maintained during leaching with poor quality water. Results showed that for reclaiming such deteriorated soils, it would be necessary to apply gypsum and preferably leach them with good quality water. When such water is scarce, low salinity sodic water could also be used for leaching.