Soil Salinity Models
The majority of the computer models available for water and solute transport in the soil (e.g. SWAP, DrainMod-S, UnSatChem ), are based on Richard's differential equation for the movement of water in unsaturated soil in combination with a differential salinity dispersion equation.
The models require input of soil characteristics like the relation between unsaturated soil moisture content, water tension, hydraulic conductivity and dispersivity. These relations vary to a great extent from place to place and are not easy to measure. The models use short time steps and need at least a daily data base of hydrological phenomena. Altogether this makes model application to a fairly large project the job of a team of specialists with ample facilities.
Simpler models, like SaltMod, based on seasonal water and soil balances and an empirical capillary rise function, are also available. They are useful for long-term salinity predictions in relation to irrigation and drainage practices.
Spatial variations owing to variations in topography can be simulated and predicted using salinity cum groundwater models, like SahysMod.
Read more about this topic: Soil Salinity Control
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