Arenic Plinthic Kandiudult
A representative soil profile of a loamy, kaolinitic, thermic Arenic Plinthic Kandiudult (Fuquay series) from North Carolina. (Photo and comments courtesy of Stan Buol, NCSU.)
This profile was photographed in Johnston County, North Carolina. These soils are common on nearly level surfaces in the upper coastal plain. This profile has a sandy surface, plowed to a depth of about 35 cm extending to between 50 and 100 cm, under lain by a fine-loamy Bt (kandic) horizon with a CEC7 less than 16 cmols kg-1 clay and an iron-rich plinthite layer between 135 and 160 cm.
The red and white mottled material below 160 cm does not harden when repeatedly wetted and dried thus is not plinthite. With the thick sandy surface such soils tend to be draughty but are excellent for flue cured tobacco production, often with supplemental irrigation.
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Arenic Plinthic Kandiudults have a layer, starting at the mineral soil surface, that has a sandy or sandy-skeletal particle-size class and is between 50 and 100 cm thick. They also have 5 to 50 percent (by volume) plinthite in one or more horizons within 150 cm of the mineral soil surface. These soils are of very small extent in the United States.
Kandiudults are the Udults that are very deep and have a kandic horizon and a clay distribution in which the percentage of clay does not decrease from its maximum amount by as much as 20 percent within a depth of 150 cm from the mineral soil surface, or the layer in which the clay percentage decreases has at least 5 percent of the volume consisting of skeletans on faces of peds and there is at least a 3 percent (absolute) increase in clay content below this layer. These soils do not have a fragipan or a horizon in which plinthite either forms a continuous phase or constitutes one-half or more of the volume within 150 cm of the mineral soil surface. Kandiudults are of moderate extent in the Southeastern United States.
Udults are the more or less freely drained, humus-poor Ultisols that have a udic moisture regime. They are in humid climates, and most receive well distributed rainfall. Most have light colored upper horizons, commonly a grayish horizon that rests on a yellowish brown to reddish argillic or kandic horizon. Some have a fragipan or plinthite, or both, in or below the argillic or kandic horizon. Udults developed in sediments and on surfaces that range from late Pleistocene to Pliocene or possibly older. Many are cultivated, either with the use of soil amendments or in a system in which they are cropped for a very few years and then are returned to forest to allow the trees to regather in their tissues the small supply of nutrients. Most of these soils have or had a forest vegetation, but some have a savanna that probably is anthropic.
For more information about describing soils, visit:
www.nrcs.usda.gov/Internet/FSE_DOCUMENTS/nrcs142p2_052523...
To download the latest version of Soil Taxonomy, 2nd Edition, 1999, visit:
www.nrcs.usda.gov/resources/guides-and-instructions/soil-...
For additional information about soil classification using Keys to Soil Taxonomy, 13th Edition, 2022, visit:
[www.nrcs.usda.gov/sites/default/files/2022-09/Keys-to-Soi...]
To download the latest version of Keys to Soil Taxonomy, 13th Edition, 2022, visit:
[www.nrcs.usda.gov/resources/guides-and-instructions/keys-...]
For an Illustrated Guide to Soil Taxonomy, visit:
www.nrcs.usda.gov/sites/default/files/2022-06/Illustrated...
Arenic Plinthic Kandiudult
A representative soil profile of a loamy, kaolinitic, thermic Arenic Plinthic Kandiudult (Fuquay series) from North Carolina. (Photo and comments courtesy of Stan Buol, NCSU.)
This profile was photographed in Johnston County, North Carolina. These soils are common on nearly level surfaces in the upper coastal plain. This profile has a sandy surface, plowed to a depth of about 35 cm extending to between 50 and 100 cm, under lain by a fine-loamy Bt (kandic) horizon with a CEC7 less than 16 cmols kg-1 clay and an iron-rich plinthite layer between 135 and 160 cm.
The red and white mottled material below 160 cm does not harden when repeatedly wetted and dried thus is not plinthite. With the thick sandy surface such soils tend to be draughty but are excellent for flue cured tobacco production, often with supplemental irrigation.
____________________________________
Arenic Plinthic Kandiudults have a layer, starting at the mineral soil surface, that has a sandy or sandy-skeletal particle-size class and is between 50 and 100 cm thick. They also have 5 to 50 percent (by volume) plinthite in one or more horizons within 150 cm of the mineral soil surface. These soils are of very small extent in the United States.
Kandiudults are the Udults that are very deep and have a kandic horizon and a clay distribution in which the percentage of clay does not decrease from its maximum amount by as much as 20 percent within a depth of 150 cm from the mineral soil surface, or the layer in which the clay percentage decreases has at least 5 percent of the volume consisting of skeletans on faces of peds and there is at least a 3 percent (absolute) increase in clay content below this layer. These soils do not have a fragipan or a horizon in which plinthite either forms a continuous phase or constitutes one-half or more of the volume within 150 cm of the mineral soil surface. Kandiudults are of moderate extent in the Southeastern United States.
Udults are the more or less freely drained, humus-poor Ultisols that have a udic moisture regime. They are in humid climates, and most receive well distributed rainfall. Most have light colored upper horizons, commonly a grayish horizon that rests on a yellowish brown to reddish argillic or kandic horizon. Some have a fragipan or plinthite, or both, in or below the argillic or kandic horizon. Udults developed in sediments and on surfaces that range from late Pleistocene to Pliocene or possibly older. Many are cultivated, either with the use of soil amendments or in a system in which they are cropped for a very few years and then are returned to forest to allow the trees to regather in their tissues the small supply of nutrients. Most of these soils have or had a forest vegetation, but some have a savanna that probably is anthropic.
For more information about describing soils, visit:
www.nrcs.usda.gov/Internet/FSE_DOCUMENTS/nrcs142p2_052523...
To download the latest version of Soil Taxonomy, 2nd Edition, 1999, visit:
www.nrcs.usda.gov/resources/guides-and-instructions/soil-...
For additional information about soil classification using Keys to Soil Taxonomy, 13th Edition, 2022, visit:
[www.nrcs.usda.gov/sites/default/files/2022-09/Keys-to-Soi...]
To download the latest version of Keys to Soil Taxonomy, 13th Edition, 2022, visit:
[www.nrcs.usda.gov/resources/guides-and-instructions/keys-...]
For an Illustrated Guide to Soil Taxonomy, visit:
www.nrcs.usda.gov/sites/default/files/2022-06/Illustrated...