salinisering

Salinisering, or salinization, is the process by which soils and water bodies accumulate soluble salts to levels that impair agricultural production and ecosystem function. It is most common in arid and semi-arid regions and in areas where irrigation is used without adequate drainage, which concentrates salts in the root zone.

Causes and mechanisms: Natural weathering releases salts that can accumulate in soils. High evapotranspiration or limited leaching causes salts to be left behind as water evaporates. Irrigation with saline or poor-quality water, rising groundwater, and coastal intrusion of seawater can introduce or mobilize salts. When drainage is inadequate, capillary rise from groundwater brings salts into the root zone.

Indicators: Soil salinity is commonly measured by the electrical conductivity of soil water (ECe or ECw); high EC indicates salinity. The sodium adsorption ratio (SAR) and pH inform potential soil structural problems and sodicity, which can accompany salinization.

Effects: Elevated salinity reduces plant water uptake through osmotic stress and can cause ion toxicity, particularly from sodium and chloride. Salt-affected soils may crust, disperse their clays, reduce infiltration, and lower soil fertility. Crop yields decline, especially for salt-sensitive species.

Management and reclamation: Prevention emphasizes adequate drainage, leaching salts beyond the root zone, and using irrigation water with low salinity. Reclamation may involve improving drainage, controlled leaching, and amendments such as gypsum to displace sodium; selecting salt-tolerant crops; and adjusting irrigation timing and quantity to minimize salt buildup.

Global relevance: Salinization affects substantial areas of agricultural land worldwide, with notable impact in regions that rely on irrigation and have limited drainage.