LOCATION RAVIA OKEstablished Series
TAXONOMIC CLASS: Fine-loamy, mixed, superactive, thermic Udic Argiustolls
TYPICAL PEDON: Ravia loam--range.
(Colors are for dry soil unless otherwise stated.)
A1--0 to 10 inches; grayish brown (10YR 5/2) loam, very dark grayish brown (10YR 3/2) moist; moderate medium granular structure; slightly hard, friable; few granitic fragments less than 3 inches in diameter; slightly acid; gradual smooth boundary. (8 to 13 inches thick)
BA--10 to 17 inches; brown (10YR 5/3) gravelly loam, dark brown (10YR 3/3) moist; moderate medium subangular blocky structure; hard, firm; about 20 percent by volume of granitic fragments less than 3 inches in diameter; moderately acid; gradual wavy boundary. (4 to 12 inches thick)
Bt1--17 to 31 inches; light yellowish brown (10YR 6/4) gravelly clay loam; yellowish brown (10YR 5/4) moist; moderate medium subangular blocky structure; very hard, firm; nearly continuous clay films on faces of peds; about 25 percent by volume of granitic fragments less than 3 inches in diameter; moderately acid; gradual wavy boundary. (8 to 16 inches thick)
Bt2--31 to 43 inches; light yellowish brown (10YR 6/4) gravelly clay loam, yellowish brown (10YR 5/4) moist; moderate medium blocky structure; extremely hard, very firm; nearly continuous clay films on faces of peds; about 20 percent by volume of granitic fragments less than 3 inches in diameter; slightly acid; gradual wavy boundary. (0 to 20 inches thick)
Bt3--43 to 50 inches; light brownish gray (10YR 6/2) gravelly clay loam, grayish brown (10YR 5/2) moist; few fine distinct yellowish brown mottles; moderate coarse blocky structure; hard, firm; nearly continuous clay films on faces of peds; about 40 percent by volume of granitic fragments less than 3 inches in diameter; neutral; clear wavy boundary. (0 to 20 inches thick)
C--50 to 72 inches; pinkish gray (7.5YR 7/2) very gravelly loam, pinkish gray (7.5YR 6/2) moist; massive; weathered granite increases with depth and loam decreases with depth; about 85 percent by volume of granitic fragments less than 3 inches in diameter; granite can be penetrated with auger; slightly alkaline.
TYPE LOCATION: Johnston County, Oklahoma; about 5-1/2 miles north and 1 mile east of Tishomingo; 2,300 feet west and 1,700 feet south of the northeast corner of sec. 2, T. 3 S., R. 6 E.
RANGE IN CHARACTERISTICS: Solum thickness ranges from 40 to 60 inches. The content of coarse fragments less than 3 inches in diameter ranges by volume from 0 to 30 percent in the A horizon, from 10 to 30 percent in the textural control section and from 30 to 90 percent below the textural control section.
The A horizon ranges from dark grayish brown to brown in hues of 10YR through 5YR, with values of 4 or 5 and chromas of 2 or 3. It is loam or sandy loam with gravelly analogies and is moderately acid or slightly acid.
The BA, Bt1 and Bt2 horizons range in color from light grayish brown through reddish brown in hues of 10YR through 5YR, values of 4 through 6 and chromas of 2 through 6. Chromas of 2 occur below a depth of 40 inches. These horizons in some pedons are mottled in shades of brown, red and yellow. These horizons are loam, sandy clay loam or clay loam with a clay content ranging from 25 to 35 percent in the BA and Bt1 horizons and up to 40 percent in the Bt2 horizon. The BA and Bt1 horizons range from slightly
acid through strongly acid and the Bt2 horizon ranges from neutral through moderately acid. The Bt3 horizon has colors similar to the Bt horizons above but generally is grayer and more mottled. It has similar textures and its reaction ranges from slightly acid through slightly alkaline.
The C horizon has shades of gray, brown, red or yellow, or it is mottled in these shades. It is gravelly or very gravelly counterparts of clay loam, sandy clay loam or loam, containing by volume from 40 to 90 percent weathered granite fragments. It ranges from neutral through slightly alkaline.
COMPETING SERIES: These are the Chickasha, Grant, Kingfisher, Klump, Naron, Shellabarger, Teller, Vanoss, and Zaneis series. Chickasha, Klump, Naron, Shellabarger, Teller, and Zaneis soils lack 10 to 30 percent fragments in the B horizon. In addition, they lack gravelly or very gravelly C horizons. Grant, Kingfisher, and Vanoss soils have fine-silty control sections.
GEOGRAPHIC SETTING: These soils occur on very gently sloping or gently sloping uplands. Slope gradients are 1 to 5 percent. The soil formed in material weathered from granite. The climate is subhumid. Average annual temperature is 62 degrees to 64 degrees F., mean annual precipitation is 38 inches, and Thornthwaite P-E index is 62 at the type location.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the Agan, Chigley, Durant, and Stephenville series. Agan, Chigley, and Stephenville soils lack a mollic epipedon. In addition, Agan soils have an abrupt textural change between the lower A and upper B horizons, and Stephenville soils have a 20- to 40-inch sola. Durant soils have more than 35 percent clay in the control section and lack 10 to 30 percent fragments in the B horizon.
DRAINAGE AND PERMEABILITY: Well drained; medium runoff; moderately slow permeability.
USE AND VEGETATION: Used mainly for native rangeland. Approximately 40 percent of these soils have been cultivated in the past.
DISTRIBUTION AND EXTENT: South-central Oklahoma and possibly northern Texas. Series is inextensive, known to comprise about 7,000 acres in Johnston County, Oklahoma.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Temple, Texas
SERIES ESTABLISHED: Johnston County, Oklahoma; 1975.
REMARKS: These soils would formerly have been classified in the Brunizem great soil group.