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FAO SOILS PORTAL

Management of Salt Affected Soils

Salt crusts on top of ridges

When salts more soluble than calcium carbonate and gypsum are present in the soil and affect crop growth and yield of most crops these soils are considered salt affected. Most of these soils have an Electrical Conductivity of more than 4 Ohms/cm. Many of them are classified as Solonchakz. The presence of salts affects the plant uptake of nutrients and the microbiological activity in the soil. Salinity may also affect other soils to a lesser extent and may; lead to recognition of saline phases which also deserve attention when present under salt-sensitive crops (spinach, etc...).

Methods adopted to remove excess salts from the soil surface and the root zone in saline soils includes:

To prevent the excessive accumulation of salt in the root zone, irrigation water (or rainfall) must be applied in excess of that needed for the evaporation of the crop.  Leaching can be timed to precede the critical growth stages at which stress should be prevented. This can be timed through irrigation during dry seasons. Leaching at times of low evapo-transpiration demands is more efficient, for example, at night, during high humidity, in cooler weather or outside the cropping season.

Leaching is only effective when salty drainage water is discharged through subsurface drains that carry the leached salts out of the area under  reclamation (But one should avoid to  contaminate other areas under cultivation downstream).