LOCATION SPADRA AR+ALEstablished Series
TAXONOMIC CLASS: Fine-loamy, siliceous, active, thermic Typic Hapludults
TYPICAL PEDON: Spadra loam on a 2 percent slope in pasture. (Colors are for moist soil unless otherwise stated.)
Ap--0 to 8 inches; dark brown (7.5YR 4/4) loam; weak medium granular structure; very friable; many medium and fine roots; strongly acid; abrupt smooth boundary. (5 to 10 inches thick)
Bt1--8 to 23 inches; reddish brown (5YR 4/4) loam; weak medium subangular blocky structure; friable; many faint clay films on faces of peds; common fine roots; common fine pores; strongly acid; gradual smooth boundary.
Bt2--23 to 36 inches; yellowish red (5YR 4/6) loam, moderate medium subangular blocky structure; friable; common common clay films on faces of peds; common fine roots;
common fine pores; very strongly acid; gradual smooth boundary. (Combined thickness of the Bt horizon ranges from 35 to 50 inches.)
BC--36 to 49 inches; yellowish red (5YR 4/6) fine sandy loam; weak medium subangular blocky structure; friable; few fine roots; few fine pores; very strongly acid; gradual smooth boundary. (0 to 20 inches thick)
C--49 to 80 inches; brown (7.5YR 4/4) fine sandy loam; massive; very friable; few fine roots; about 2 percent by volume rounded gravel less than 3 inches in diameter; very strongly acid.
TYPE LOCATION: Johnson County, Arkansas; 3/8 mile south of Interstate Highway 40; 100 yards east of Clarksville Sewage Lagoon; about 50 yards west of Spadra Creek; NE1/4NW1/4SW1/4 sec. 8, T. 9 N., R. 23 W.
RANGE IN CHARACTERISTICS: Solum thickness ranges from 40 to 60 inches and depth to bedrock is more than 72 inches. Reaction ranges from medium acid to very strongly acid throughout unless limed. Coarse fragments, 1/4 to 3 inches in diameter, ranges from 0 to 15 percent by volume in the A horizon, BA horizon, where present, and Bt horizons; and 0 to 35 percent by volume in the BC and C horizons. The particle size control section contains 18 to 35 percent clay and more than 30 percent silt.
The A horizon has hue of 10YR or 5YR, value of 4, and chroma of 2, 3 or 4, or value of 3, and chroma of 4, or hue of 7.5YR, value of 4, and chroma of 2 or 4, or value of 3, and chroma of 4. Texture is fine sandy loam, loam, or silt loam.
The BA horizon, where present, has hue of 5YR, 7.5YR or 10YR, value of 4 or 5, and chroma of 4 or 6. Texture is fine sandy loam, loam or silt loam.
The Bt horizon has hue of 5YR, value of 4 or 5, and chroma of 4 or 6, or value of 3, and chroma of 4; or hue of 7.5YR, value of 4 or 5, and chroma of 4 or 6. Some pedons have hue of 10YR, value of 4 or 5, and chroma of 4 or 6 in the lower part. Mottles range from none to common in shades of red, brown or yellow. Texture is loam, sandy clay loam, clay loam. Subhorizons maybe silt loam, or silty clay loam.
The BC and C horizons have hue of 10YR, 7.5YR or 5YR, value of 4 or 5, and chroma of 4 or 6. Mottles range from none to many in shades of red, brown or yellow. Texture is loam, sandy loam, fine sandy loam, gravelly loam, gravelly sandy loam or gravelly fine sandy loam..
COMPETING SERIES: These include the Apison, Cahaba, Durham, Emporia, Euharlee, Granville, Hartsells, Kempsville, Linker, Nauvoo, Oktaha, Olla, Pirum, Sipsey, Smithdale, Stringtown, Suffolk, and Vaucluse series. Apison, Hartsells, Linker, Oktaha and Sipsey soils have solum thickness and depth to bedrock of less than 40 inches. Cahaba soils contain mica flakes and generally redder hues in the upper Bt horizon. Durham soils contain mica flakes in the lower solum and are underlain by saprolite weathered from granite, gneiss or schist. Emporia soils contain gray mottles below a depth 36 inches and has a seasonally high water table within 3 to 4.5 feet of the surface. Euharlee soils contains E horizons and are moderately slowly permeable. Granville soils contain less than 30 percent silt in the particle-size control section and more than 6 meq/100g of exchangeable aluminum. Kempsville soils contain Bt horizons that are brittle and somewhat compact in as much as 40 percent of the mass. Nauvoo soils have a solum thickness of 30 to 50 inches and soft bedrock at 40 to 60 inches. Olla soils have sola of 30 to more than 70 inches thick, chroma 2 mottles in the BC horizon and chroma 2 colors in the C horizon. Pirum soils have a solum thickness and depth to bedrock of 22 to 50 inches. Smithdale soils have sola greater than 60 inches thick. Stringtown soils contain ironstone fragments throughout and 1 to 4 percent plinthite. Suffolk soils have a 30 to 50 inch solum and contain less than 30 percent silt in the particle-size control section. Vaucluse soils contain ironstone fragments and Bt horizons that are dense, brittle and slightly cemented in 10 to 50 percent of the mass.
GEOGRAPHIC SETTING: Spadra soils are on level to gently sloping stream terraces. Slopes are dominantly 0 to 3 percent but range up to 5 percent. The soil formed in loamy alluvium from interbedded sandstone, siltstone, and shale uplands. Near the type location the average annual temperature is 61 degrees F.; the average annual precipitation is 46 inches.
GEOGRAPHICALLY ASSOCIATED SOILS: These include Barling, Ceda, Cleora, Enders, Kenn, Leadvale and Nella series. Barling, Ceda and Cleora soils are on flood plains and do not have argillic horizons. Enders soil are on adjacent sideslopes and have a clayey control section. Kenn soils are on flood plains and low terraces and have very gravelly substrata and higher base saturation. Leadvale soils are in adjacent valleys and have a fragipan. Nella soils are on adjacent sideslopes and have sola greater than 60 inches thick.
DRAINAGE AND PERMEABILITY: Well drained; slow to medium runoff; moderate permeability. Some areas are subject to occasional flooding for brief periods in winter and early spring.
USE AND VEGETATION: Cleared areas are used for production of corn, soybeans, small grains, and pasture. The native vegetation was forest of oaks, sweetgum, black walnut, and shortleaf pine.
DISTRIBUTION AND EXTENT: Boston Mountains and Arkansas Valley in Arkansas and Oklahoma, and Sand Mountains in Alabama. The series is moderately extensive, with about 16,000 acres mapped in county of type location.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Morgantown, West Virginia
SERIES ESTABLISHED: Johnson County, Arkansas; 1972.
REMARKS: Diagnostic horizons recognized in this pedon are:
Ochric epipedon--surface to 8 inches.
Argillic horizon--8 to 36 inches.
The Spadra series formerly would have been classified in the Gray-Brown Podzolic great soil group. These soils were mapped in the Sequatchie series.
ADDITIONAL DATA: Characterization of the typical pedon by the University of Arkansas Soil Characterization Laboratory. Pedon number-80JH01.