LOCATION NELLA TN+AL AR GAEstablished Series
The Nella series consists of very deep, well drained, moderately permeable soils. These soils formed in alluvium or colluvium and in residuum of limestone, sandstone and shale. They are on hillsides, benches and foot slopes. Slopes range from 2 to 60 percent.
TAXONOMIC CLASS: Fine-loamy, siliceous, semiactive, thermic Typic Paleudults
TYPICAL PEDON: Nella cobbly loam--forested. (Colors are for moist soil)
A--0 to 1 inch; dark grayish brown (10YR 4/2) cobbly loam; weak medium and fine granular structure; very friable; many fine and medium roots; 20 percent angular fragments of sandstone up to 4 inches in diameter; strongly acid; abrupt smooth boundary. (0 to 5 inches thick)
E--1 to 8 inches; brown (10YR 5/3) cobbly loam; weak medium and fine granular structure; very friable; many fine and medium roots; 20 percent angular fragments of sandstone up to 4 inches in diameter; strongly acid; clear smooth boundary. (0 to 8 inches thick)
BE--8 to 14 inches; strong brown (7.5YR 5/6) cobbly loam; weak medium and fine subangular blocky structure; friable; many fine and medium roots; 20 percent angular fragments of sandstone up to 4 inches in diameter; strongly acid; clear smooth boundary. (0 to 8 inches thick)
Bt1--14 to 24 inches; yellowish red (5YR 4/6) cobbly clay loam; moderate medium subangular blocky structure; friable; common fine and medium roots; 15 percent angular fragments of sandstone up to 5 inches in diameter; common faint clay films on faces of peds; strongly acid; gradual smooth boundary.
Bt2--24 to 36 inches; yellowish red (5YR 5/6) cobbly clay loam; few fine distinct red (2.5YR 4/6) and few medium prominent yellowish brown (10YR 5/4) mottles; moderate medium subangular blocky structure; friable; few fine roots; 20 percent angular fragments of sandstone up to 5 inches in diameter; common distinct clay films on faces of peds; very strongly acid; gradual smooth boundary.
Bt3--36 to 50 inches; yellowish red (5YR 5/6) cobbly clay loam; common medium distinct red (2.5YR 4/6), dark red (2.5YR 3/6), and few fine prominent yellowish brown (10YR 5/6) mottles; moderate medium subangular blocky structure; friable; few fine roots; 25 percent angular fragments of sandstone up to 5 inches in diameter; common distinct clay films on faces of peds; very strongly acid; gradual smooth boundary.
Bt4--50 to 70 inches; red (2.5YR 5/6) cobbly clay loam; many medium faint dark red (2.5YR 3/6) and common medium and fine prominent strong brown (7.5YR 5/6) mottles; weak medium subangular blocky structure; friable; few fine roots; 25 percent angular fragments of sandstone up to 6 inches in diameter; common distinct clay films on faces of peds; very strongly acid. (Thickness of the Bt horizon is more than 45 inches)
TYPE LOCATION: White County, Tennessee; one mile east of Sparta; 100 yards south of water tower; 75 feet north of gravel road.
RANGE IN CHARACTERISTICS: Solum thickness is greater than 60 inches. Depth to bedrock is 6 feet or more. Reaction is very strongly acid or strongly acid except the surface layer is less acid where limed. Rock fragments range from 15 to about 35 percent in each horizon. The fragments are mostly sandstone and range from 0.25 inch to about 20 inches in diameter.
The A horizon has hue of 10YR or 7.5YR, value of 3 to 5, and chroma of 2 to 4. The Ap horizon has hue of 10YR or 7.5YR, value of 4 to 6 and chroma of 3 to 6 except severely eroded areas also have hue of 5YR and chroma of 8. The E horizon has hue of 10YR or 7.5YR, value of 4 to 6 and chroma of 2 to 4. The fine earth fraction of the A and E horizons are loam, fine sandy loam, sandy loam, or rarely silt loam. Severely eroded areas are also sandy clay loam or clay loam in some pedons.
Many pedons have a transitional horizon between the A or E and the Bt horizon.
The Bt horizon has hue of 5YR or 2.5YR, value of 4 to 6 and chroma of 6 or 8. In some pedons, the Bt horizon also has hue of 7.5YR in the upper part and value of 3 in the lower part. Mottles are in shades of brown, yellow and red. The fine earth fraction is clay loam or sandy clay loam except the upper part ranges to loam and the lower part ranges to clay or sandy clay in some pedons. In the particle size control section, clay content averages between 25 and 35 percent, sand content between 20 and 55 percent and silt content is more than 20 percent.
COMPETING SERIES: Soils in the same family are the Allen, Dubach, Etowah, Holston, Ruston, Sailes, Silsbee, and Warnock series. Soils in closely related families are the Addielou, Avilla, Bama, Ironcity, Leesburg, Lytle, Minvale, Noboco, Octavia, and Pikeville series. Allen soils have less than 15 percent rock fragments in the B horizon. Dubach soils formed in loamy sediments on Coastal Plain stream terraces. Etowah soils have A horizons with value of 3 and less than 15 percent fragments. Holston, Noboco, and Leesburg soils have hue of 10YR or 7.5YR in the Bt horizon. Ruston soils are bisequel. Sailes soils formed in loamy marine sediments on the Coastal Plain on broad interstream divides. Silsbee soils formed in loamy sediments of early to mid Pleistocene age. Warnock soils contain less than 15 percent fragments and the lower part of the Bt horizon has gray mottles is brittle in some pedons. Addielou soils have an A horizon more than 20 inches thick. Avilla and Pikeville soils have up to 70 fragments in the lower part. Bama soils are free of rock fragments. Ironcity and Octavia soils have clayey 2Bt horizons. Leesburg and Minvale soils have sandstone or chert gravels in the Bt horizon. Lytle soils formed from loess-mantled coastal plain sediments. Noboco soils have redox depletions and accumulations associated with seasonal wetness within 30 to 48 inches of the surface.
GEOGRAPHIC SETTING: Nella soils are on hillsides, benches and foot slope. Slopes range from 2 to 60 percent. These soils formed in loamy alluvium or colluvium and in residuum of limestone, sandstone and shale. Mean annual temperature is 60 degrees F., and mean annual precipitation is 54 inches near the type location.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the competing Allen, Etowah, and Holston series and the Bouldin and Jefferson series. Bouldin soils are on the sides of mountains and are loamy-skeletal. Jefferson soils are on the sides of mountains and foot slopes. They are Hapludults and have hues of 10YR or 7.5YR in the Bt horizon.
DRAINAGE AND PERMEABILITY: Well drained. Runoff is medium on gentle slopes and rapid on the steeper slopes. Moderate permeability.
USE AND VEGETATION: About one-third is in forest consisting chiefly of oaks, hickories, yellow poplar, beech, and shortleaf and Virginia pine. Cleared areas are used chiefly for pasture but a few areas are cropped to tobacco, corn, truck, and small grain.
DISTRIBUTION AND EXTENT: The Appalachian Ridges and Valleys, Highland Rim, and Cumberland Plateau and Mountains in Tennessee and in Northwest Georgia, Northern Alabama, and Arkansas. The series is of large extent.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Morgantown, West Virginia
SERIES ESTABLISHED: Johnson County, Arkansas; 1973.
REMARKS: The 8/01 revision assigns a semiactive CEC activity class to the series.
Diagnostic horizons in this pedon are:
Ochric epipedon- 0 to 8 inches (Ap horizon)
Argillic horizon- 14 to 70 inches (Bt horizon)