Salt leaching and the effect of gypsum application in a saline-sodic soil

Field leaching studies in representative mixed Hyperthermic Salic Calciorthids showed that for 80% reduction in profile salinity, 0.4 cm leaching water/cm soil depth was required to be passed through the soil. This corresponded to 1.14 pore volume displacement. From four different predictive models, Burns' model, which is theoretically based and requires knowledge of simple parameters, was found to be highly predictive. Dieleman's empirical relationship also adequately described field leaching data. Desalinization of the profile was accompanied by simultaneous reduction in the SAR of the soil solution. When leached in the presence of gypsum, the SAR was reduced to a greater extent in lower depths which would otherwise have been achieved by passing additional quantities of water. Results have been discussed in view of the possible need or otherwise of amendments during reclamation of soils having excess neutral salts and a high SAR of soil solution (saline-sodic soils).