Effect of Hydrated Lime and Gypsum on the Leachate and Sodium Removal from the B Horizon of a Natric Soil

Laboratory leaching studies on the B horizon of Huey silt loam, a natric soil in south-central Illinois were conducted to study the comparative effect of hydrated lime, gypsum applied as slurry and gypsum applied as dry powder on the leachate and sodium removal from the soil columns. The ameliorants were applied @ 0,1 and 2% by weight of soil. Three phases of leaching were used, each separated by about 6 weeks of drying between two successive phases. The effectiveness of the ameliorants was in the order of gypsum slurry ≈ gypsum dry > hydrated lime, and that of levels of ameliorants was in the order of 2% > 1% > 0%. Study of some physical and chemical properties of the soils from the leached columns indicated that hydrated lime decreased the bulk density and increased the amount of CaCO₃ compared to gypsum. It is suggested that much of the hydrated lime was used up in the formation of CaCO₃ and in pozzolanic reaction leaving little Ca⁺⁺ in soil system to replace Na⁺ from the exchange complex.