For a snapshot on salinity and diagnosis refer to the MyCrop salinity fact sheet. More detailed information is provided below.
Estimating the extent of dryland salinity
Landholders and scientists have several ways of estimating the extent and location of dryland salinity, including estimating or measuring the actual area of salt scald (no plant growth), measuring areas of severely reduced plant growth, and calculating the area with shallow saline watertables (from bore data).
Monitoring trends in groundwater levels provides information needed to estimate the likelihood of dryland salinity expanding and the timing of the predicted expansion.
Estimates of current and projected extent of salinity in WA have been published by the Australian Bureau of Statistics, Department of Agriculture, National Land and Water Resources Audit, the Land Monitor project and Salinity Investment Framework.
The opportunity cost of lost agricultural production from dryland salinity in the south-west of WA was calculated to be at least $344 million per annum. Dryland salinity does not affect all farmers equally.
The last scientific evaluation of the extent of salinity in Western Australia identified between 0.9 and 1.1Mha was severely affected. Private land accounted for between 0.74 and 0.84Mha. The impact of dryland salinity on agricultural crops is variable.
Dryland salinity remains a potential threat to 2.8–4.5 million hectares of productive agricultural land and depending on future climate, the area actually affected will increase. The long-term extent of salinity may take decades to centuries to develop, especially in areas where clearing was staggered, the area cleared is small, or where watertables are deep.