Department of Soil Science, CCS Haryana Agricultural University, Hisar, Haryana, 125004.
* Present address: Department of Soil Science, College of Agriculture, Shahid Chamran University, Ahwaz, Iran.
Studies on Na-Ca exchange equilibria at five levels of total electrolyte concentration (i.e., TEC 25, 100,200 and 500 mequiv. VI) in relation to CaCO3 (i.e., 0 and 5%) were carried out in a loamy sand (Mayer), sandy loam (Bokhari) and clay loam (Hansi) soil samples from Haryana state. The results were analysed using different exchange equations. Statistical relationships were worked out between exchange selectivity coefficients and TEC (or ESR or ESP). The values of Gap on selectivity coefficient (KG*, calculated from concentrations) gradually increased with the increase in TEC. The other exchange selectivity coefficients (i.e., KG, KKDO' K and K calculated from activities) also increased with the increase in TEC. The effect of CaCO3 on KG* vs TEC was best fitted with the second degree polynomial and KG* vs ESR with a straight line fit.
Sodium-Ca exchange, electrolyte concentration, selectivity coefficients, calcium carbonate