Aquisalid and landscape
Aquisalid Landscape, central Nevada — Salt crusts are visible at the soil surface in this Basin and Range landscape. Salts accumulate in low-lying areas of the basin as surface runoff and seasonal high water tables transport dissolved salts to or close to the soil surface. As water evaporates, the salts are left behind. Few plants are able to tolerate areas of the basin where high salt concentrations are greatest. (Image from the Soil Science Society of America Marbut Memorial Slide Set) (Notes and photo downloaded from: www.uidaho.edu/cals/soil-orders/aridisols)
Aquisalids are the salty soils in wet areas in the deserts where capillary rise and evaporation of water concentrate the salts near the surface. Some of these soils have redoximorphic depletions and concentrations. In other soils redoximorphic features may not be evident because of a high pH and the associated low redox potential, which inhibit iron and manganese reduction. These soils occur dominantly in depressional areas where ground water saturates the soils at least part of the year. The vegetation on these soils generally is sparse, consisting of salt-tolerant shrubs, grasses, and forbs. Although these soils may hold water at a tension less than 1500 kPa, the dissolved salt content makes the soils physiologically dry.
Salids are the Aridisols that have a salic horizon that has its upper boundary within 100 cm of the soil surface. Salids are most common in depressions (playas) in the deserts or in closed basins in the wetter areas bordering the deserts. In North Africa and in the Near East, such depressions are referred to as Sebkhas or Chotts, depending on the presence or absence of surface water for prolonged periods. Under the arid environment and hot temperatures, accumulation of salts commonly occurs when there is a supply of salts and a net upward movement of water in the soils. In some areas a salic horizon has formed in salty parent materials without the presence of ground water.
The most common form of salt is sodium chloride (halite), but sulfates (thenardite, mirabilite, and hexahydrite) and other salts may also occur. The concept of Salids is one of accumulation of an excessive amount of salts that are more soluble than gypsum. This is implicit in the definition, which requires a minimum absolute EC of 30 dS/m in 1:1 extract (about 2 percent salt) and a product of EC and thickness of at least 900. As a rule, Salids are unsuitable for agricultural use, unless the salts are leached out. Leaching the salts is an expensive undertaking, particularly if there is no natural outlet for the drainage water. Two great groups are recognized—Aquisalids, which are saturated with water for 1 month or more during the year, and Haplosalids, which are drier.
For additional information about U.S. Soil Taxonomy, visit:
www.nrcs.usda.gov/wps/portal/nrcs/detail/soils/survey/cla...
Aquisalid and landscape
Aquisalid Landscape, central Nevada — Salt crusts are visible at the soil surface in this Basin and Range landscape. Salts accumulate in low-lying areas of the basin as surface runoff and seasonal high water tables transport dissolved salts to or close to the soil surface. As water evaporates, the salts are left behind. Few plants are able to tolerate areas of the basin where high salt concentrations are greatest. (Image from the Soil Science Society of America Marbut Memorial Slide Set) (Notes and photo downloaded from: www.uidaho.edu/cals/soil-orders/aridisols)
Aquisalids are the salty soils in wet areas in the deserts where capillary rise and evaporation of water concentrate the salts near the surface. Some of these soils have redoximorphic depletions and concentrations. In other soils redoximorphic features may not be evident because of a high pH and the associated low redox potential, which inhibit iron and manganese reduction. These soils occur dominantly in depressional areas where ground water saturates the soils at least part of the year. The vegetation on these soils generally is sparse, consisting of salt-tolerant shrubs, grasses, and forbs. Although these soils may hold water at a tension less than 1500 kPa, the dissolved salt content makes the soils physiologically dry.
Salids are the Aridisols that have a salic horizon that has its upper boundary within 100 cm of the soil surface. Salids are most common in depressions (playas) in the deserts or in closed basins in the wetter areas bordering the deserts. In North Africa and in the Near East, such depressions are referred to as Sebkhas or Chotts, depending on the presence or absence of surface water for prolonged periods. Under the arid environment and hot temperatures, accumulation of salts commonly occurs when there is a supply of salts and a net upward movement of water in the soils. In some areas a salic horizon has formed in salty parent materials without the presence of ground water.
The most common form of salt is sodium chloride (halite), but sulfates (thenardite, mirabilite, and hexahydrite) and other salts may also occur. The concept of Salids is one of accumulation of an excessive amount of salts that are more soluble than gypsum. This is implicit in the definition, which requires a minimum absolute EC of 30 dS/m in 1:1 extract (about 2 percent salt) and a product of EC and thickness of at least 900. As a rule, Salids are unsuitable for agricultural use, unless the salts are leached out. Leaching the salts is an expensive undertaking, particularly if there is no natural outlet for the drainage water. Two great groups are recognized—Aquisalids, which are saturated with water for 1 month or more during the year, and Haplosalids, which are drier.
For additional information about U.S. Soil Taxonomy, visit:
www.nrcs.usda.gov/wps/portal/nrcs/detail/soils/survey/cla...