Soil salinity

Soil salinity is the accumulation of soluble salts in soil to levels that impair plant growth. It limits water uptake and can disrupt plant nutrition and soil structure.

Osmotic stress: Osmotic stress occurs when differences in solute concentration make water harder for cells to absorb or retain. Salty soil lowers water potential, making water uptake difficult even when soil appears moist.
Irrigation-induced salinity: Irrigation-induced salinity is salt accumulation caused by irrigation water and inadequate drainage or leaching. Poorly managed irrigation is a major cause of salinized agricultural land.
Soil leaching: Soil leaching is the downward transport of dissolved substances through soil by percolating water. Applying suitable water can move soluble salts below the crop root zone.
Land degradation: Land degradation is the persistent decline in land's biological or productive capacity. Severe soil salinity is one pathway by which productive land becomes degraded.
Sodicity: Sodicity is an excess of exchangeable sodium relative to other cations in soil. Sodium-rich salinity can disperse clay, reducing infiltration and damaging soil structure.
Saline groundwater: Saline groundwater contains dissolved salts at concentrations above those of fresh water. Shallow saline groundwater can move upward and leave salts near the soil surface.
Agricultural drainage: Agricultural drainage removes excess water from farmland through surface or subsurface systems. Drainage carries leached salts away and helps prevent their return to roots.
Crop yield: Crop yield is the harvested output of a crop per unit of land or production input. Salinity reduces yields by restricting water uptake and disturbing plant function.
Ion toxicity: Ion toxicity is cellular damage caused by excessive concentrations of particular ions. Plants in saline soils may accumulate toxic sodium or chloride in their tissues.
Evaporation: Evaporation is the change of liquid water into vapor at a surface. In dry climates, evaporation removes water while leaving dissolved salts behind.

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