Background and World-Wide Distribution of Salt-Affected Soils

Soil salinity is an increasing problem of global concern of environmental degradation and food insecurity. Primary salinization of soils results when precipitation exceeds evaporation. In addition, the influence of the sea and parent material of pedogenesis, which is rich in salts, may contribute to primary salinization. Ecologically valuable salt meadows are habitats of halophytes that are adapted to high salt concentrations. In contrast to primary salinization, secondary salinization is man-made due to improper irrigation and soil management. Fertile alluvial soils are prone to devastation particularly in semi-arid and arid countries if large amounts of salts are imported with irrigation water. Due to the distribution of salt-affected soils in the subtropical zones north and south of the equator, many low-income and lower-middle-income countries are endangered by food shortages. There are historical examples that food shortages caused by insufficient plant production after salinization of soils or water deficit contributed to the decline of advanced civilizations.