salinization

Salinization is the accumulation of water-soluble salts in soil, on the soil surface, or in groundwater, leading to increased salinity that can impair plant growth and degrade soil structure and ecosystem functions. It occurs in natural conditions and as a result of human activities such as irrigation, drainage management, and land-use changes.

Natural salinization develops in arid and semi-arid regions where high evaporation concentrates salts in the soil and salts are slowly released from weathered minerals. Human-caused salinization often arises in irrigated lands when drainage is inadequate, irrigation water contains salts, or the water table rises and brings salts into the root zone through capillary rise. Coastal areas can experience groundwater salinization due to seawater intrusion, especially where freshwater supplies are depleted.

Common salts involved include sodium chloride, calcium and magnesium sulfates and chlorides, bicarbonates, and boron in some soils. The presence of soluble salts reduces soil fertility by creating osmotic stress for plants, limiting water uptake, and, in some cases, causing specific ion toxicities. Sodium can alter soil structure, reducing permeability and aeration, which exacerbates salinity effects over time.

Measurement and management: soil salinity is commonly assessed by the electrical conductivity of a soil paste or saturated extract (ECe). Management strategies include improving drainage, ensuring adequate leaching of salts, using salt-tolerant crops, adopting efficient irrigation practices, and applying soil amendments such as gypsum to sodic soils. In some cases, blending or treating irrigation water and restoring natural hydrology are pursued.

Salinization remains a significant concern in many arid and semi-arid regions, affecting agricultural productivity, water quality, and ecosystem health.