Solonchaks are widespread in the arid and semi-arid climatic zones and coastal regions in all climates. The global extent of Solonchaks is estimated to be between 2.6 million and 3.4 million km2. The level of salinity for diagnostic purposes cause the differences in the estimations.
Solonchaks are a strongly saline soil types with high concentration of soluble salts. They occur where saline groundwater comes near to the surface or where the evapo-transpiration is considerably higher than precipitation, at least during a large part of the year. Salts dissolved in the soil moisture remain behind after evaporation of the water and accumulate at or near the surface. Their morphology, characteristics and limitations to plant growth depend on the amount, depth and composition of the salts.
Land use options on Solonchak soils are largely limited by the salt content. The salts magnify drought stress because dissolved electrolytes create an osmotic potential that affects water uptake by plants. A possible way of reclamation is to flush salts out from the soil. However, most Solonchaks can be used for extensive grazing. Solonchak soils in many cases form unique ecosystems worth protecting for their biodiversity and landscape values.
Solonchaks are often cited as saline soil and salt-affected soil in international nomenclatures.