Viability of lime and gypsum use in mitigating sodicity in an irrigated vertosol

Abstract

The use of gypsum, and to a lesser extent, lime to mitigate sodicity in dryland agriculture has been shown as viable. However, under an increased water application (i.e. irrigation) the dissolution of gypsum could be expected to be more rapid. Lime, due to a lower solubility, could provide a more constant source of calcium to the soil, especially when applied in combination with gypsum. This study investigates the effects of various rates of lime, gypsum and lime/gypsum combinations on an irrigated sodic Brown Vertosol in western NSW. The expected increase in soil EC due to gypsum was not evident after 6 months due to leaching. Additionally, only a high rate lime/gypsum combination was shown to have a positive effect on exchangeable calcium and sodium percentages, as well as aggregate stability. Short-term viability was not assessed efficacious after 6 months for any treatment. Potential for long-term viability was exhibited.