Saline and Alkaline Soils

• Saline, alkaline, or saline-alkaline soils negatively affect plant growth and are called halomorphic soils.
• The type of halomorphic soil depends on the percent of total soluble salts that is sodium content.

Saline Soils

• Characterized by a high concentration of soluble salts.
• Impairs plant growth and productivity.
• Electrical conductivity (EC) of soil saturation extract exceeds 4 dS cm-1.
• pH is typically below 8.5.

Alkaline Soils

• Have a high pH.
• Contain a high proportion of exchangeable sodium ions.
• Leads to poor soil structure and reduced infiltration rates.
• pH is typically greater than 8.5.

Impact of Saline Soils

• Leads to reduced plant growth and crop yields
• Causes nutrient imbalances
• Results in soil structure degradation.

Impact of Alkaline Soils

• Leads to reduced plant growth and crop yields
• Causes nutrient deficiencies
• Creates difficulties in soil management and reclamation.

Salt-Affected Soil Locations

• Occur mainly in arid and semi-arid regions.
• Arid regions receive less than 25 centimeters of rain per year.
• Semi-arid regions receive 25 to 50 centimeters of rain per year.
• Agro-climatic conditions lead to accumulation of salts such as NaCl, Na2 SO4, MgSO4, MgCl2, CaSO4, or CaCO3 in the upper soil layers.

Conditions Causing Excess Salts

• Evapotranspiration in dry regions occurs in excess of precipitation, leaving a residue of inorganic salt on the soil surface.
• Rise in ground water carries salts to the surface, which remain after the water recedes.

Reclamation and Management

• Establish appropriate drainage systems to remove excess salty water, when poor drainage is the cause of salinity.
• Leaching excess salt involves heavy application of low salt irrigation water on permeable soils with adequate drainage.
• Applying organic mulch on the soil surface lowers surface evaporation and reduces salt movement.
• In saline-sodic and sodic (alkaline) soils, leach but avoid water low in salt to manage exchangeable sodium.

Further Management Methods

• Apply light irrigation frequently to keep soil moist and dilute salts to lessen toxic and osmotic effects.
• Avoid planting in the center of wide ridges and the tops of narrow ridges or moulds, as salt concentrations are high.
• Cultivate crops tolerant or resistant to salty environment, such as cotton, sorghum and barley, to manage saline and alkaline lands.
• Practice crop rotation to build up soil structure and improve its stability.