Dryland Salinity

Photo: Panorama of salinity site in western Victoria

The term dryland salinity is commonly used to describe the land degradation problems of increasing salt in soils and increasing salt concentrations in watercourses. The strict definition of dryland salinity refers to all salinity in non-irrigation areas, both that which has been around for thousands of years (primary or natural salinity) and that which has developed in the last two generations (secondary or induced salinity).

The increase in salt levels in the soil, which has come about through changes in land-use over the last 200 years, became evident in the 1940's. Tree clearing and common agricultural practices, such as fallowing, have caused groundwater levels to rise. The rising groundwater dissolves salt stored in soil and rock. Where the groundwater rises to within two metres of the ground surface, discharge of salty groundwater usually occurs to the soil.

The total area of secondary dryland salinity in Victoria is around 120 000 hectares. The salinity area is 1.0% of the dryland agricultural area in the state. Dryland agricultural area is land which is totally cleared (or naturally treeless) and that which is not irrigation or urban land. Dryland salinity is a soil problem that causes millions of dollars in lost productivity annually in dryland agricultural areas of Victoria.