Natraqualf TH
A soil profile of a poorly drained Natraqualf in Thailand. The sandy surface layer is underlain by a pinkish gray subsoil beginning at a depth of about 15 cm. The subsoil has a weak grade of prismatic structure and a high content of sodium. This soil is used for rice production. Note the water table at a depth of about 145 cm. (Soil Survey Staff. 2015. Illustrated guide to Soil Taxonomy. U.S. Department of Agriculture, Natural Resources Conservation Service, National Soil Survey Center, Lincoln, Nebraska)
Natraqualfs have a clay-enriched subsoil with high levels of sodium saturation (natric horizon). Typically, ground water perches above the natric horizon at some period and saturates the soil at another period. Natraqualfs are allowed, but not required, to have a glossic (degraded argillic) horizon. In the United States, most of these soils have a mesic, thermic, or hyperthermic temperature regime but a few are frigid. If undisturbed,
Natraqualfs commonly have a thin A horizon overlying a thin albic (light-colored and leached) horizon that, in turn, overlies the natric subsoil horizon. If the soils are plowed, the two upper horizons and part of the natric horizon or only part of the two upper horizons may be mixed. In the United States, the vegetation on Natraqualfs before cultivation was most commonly grass or mixed grass and drought-tolerant trees. In humid regions where annual precipitation is 100 cm or more, the presence of sodium generally is attributed to very slow permeability in the natric horizon. The permeability is so slow that there is thought to be less leaching of sodium than there is release of sodium by the weathering of feldspars. Many Natraqualfs in the United States formed in loess or alluvium of Wisconsinan age. Some Natraqualfs are in basins or on lowlands and are subject to flooding, and the sodium in them may be supplied by salty ground water or sea water. Characteristically, areas of Natraqualfs are small
For additional information about soil classification, visit:
www.nrcs.usda.gov/wps/portal/nrcs/detail/soils/survey/cla...
Natraqualf TH
A soil profile of a poorly drained Natraqualf in Thailand. The sandy surface layer is underlain by a pinkish gray subsoil beginning at a depth of about 15 cm. The subsoil has a weak grade of prismatic structure and a high content of sodium. This soil is used for rice production. Note the water table at a depth of about 145 cm. (Soil Survey Staff. 2015. Illustrated guide to Soil Taxonomy. U.S. Department of Agriculture, Natural Resources Conservation Service, National Soil Survey Center, Lincoln, Nebraska)
Natraqualfs have a clay-enriched subsoil with high levels of sodium saturation (natric horizon). Typically, ground water perches above the natric horizon at some period and saturates the soil at another period. Natraqualfs are allowed, but not required, to have a glossic (degraded argillic) horizon. In the United States, most of these soils have a mesic, thermic, or hyperthermic temperature regime but a few are frigid. If undisturbed,
Natraqualfs commonly have a thin A horizon overlying a thin albic (light-colored and leached) horizon that, in turn, overlies the natric subsoil horizon. If the soils are plowed, the two upper horizons and part of the natric horizon or only part of the two upper horizons may be mixed. In the United States, the vegetation on Natraqualfs before cultivation was most commonly grass or mixed grass and drought-tolerant trees. In humid regions where annual precipitation is 100 cm or more, the presence of sodium generally is attributed to very slow permeability in the natric horizon. The permeability is so slow that there is thought to be less leaching of sodium than there is release of sodium by the weathering of feldspars. Many Natraqualfs in the United States formed in loess or alluvium of Wisconsinan age. Some Natraqualfs are in basins or on lowlands and are subject to flooding, and the sodium in them may be supplied by salty ground water or sea water. Characteristically, areas of Natraqualfs are small
For additional information about soil classification, visit:
www.nrcs.usda.gov/wps/portal/nrcs/detail/soils/survey/cla...