The effects of lime, gypsum and lime/gypsum combinations, after 2.5 years, on two sodic soils under dryland cropping conditions in the Macquarie Valley, NSW

Abstract

While gypsum, and to a lesser extent lime, are reported as ameliorants for soil sodicity, there is relatively little information concerning the use of these ameliorants in combination. This study investigates the use of lime and gypsum combinations on selected soil properties relating to sodicity on two different soils used for dryland cropping in the Macquarie Valley of New South Wales (NSW). Lime and gypsum treatments were applied to two soils (lime [L] and/or gypsum [G], applied at t/ha rates: L0G0 [control], L2.5G0, L0G2.5, L2.5G2.5, L2.5G5, L5G2.5, and L5G5) that were sampled after 2.5 years and analysed for soil pH, EC and aggregate stability. Changes in pH and EC, as well as correlations, suggest that lime has dissolved more readily in the presence of gypsum. While aggregate stability was not significantly enhanced, significant relationships between soil EC and aggregate stability were found.