Assessment methods

Some of the commonest methods for measuring salinization include:

  • Electrical conductivity as a measure of salinity: Salinity in soils can be estimated conveniently from the electrical conductivity (EC) of a soil solution.


  • Leaching fraction: Simple empirical approach developed by Shaw and Thorburn (1985) to predict salt leaching for dryland soils and which is also applicable to irrigation.


  • Root zone salinity: Plants respond to salinity throughout the root zone, so it is useful to be able to convert measurements at various depths in the root zone into a single number that can be used when considering plant response.


  • Sodicity in soils and waters
    • ESP (Exchangeable sodium percentage), which is the proportion of sodium adsorbed onto the clay mineral surfaces as a proportion of the total cation exchange capacity
    • SAR (Sodium adsorption ratio), which is the relative concentration of sodium to calcium and magnesium in the soil solution or (irrigation) water.


  • Salinization mapping

Remote sensing, contact & non-contact ground-based geophysical methods to assess:

  • The mass and extent of salt in the landscape can be estimated
  • Areas of potential salinity hazard and salt loads likely to be mobilised under a wetter equilibrium

Commonly used remote sensing methods:

  • Aerial photography
  • Thematic Mapping (TM)
  • Airborne multi-spectral scanner (MSS)
  • Airborne geophysics.