LOCATION RAYBURN TX+LAEstablished Series
TAXONOMIC CLASS: Fine, smectitic, thermic Vertic Hapludalfs
TYPICAL PEDON: Rayburn fine sandy loam--forest.
(Colors are for moist soil unless otherwise stated.)
A--0 to 5 inches; very dark grayish brown (10YR 3/2) fine sandy loam; weak medium granular structure; very friable, soft; common fine roots; strongly acid; clear smooth boundary. (3 to 10 inches thick)
E--5 to 7 inches; dark grayish brown (10YR 4/2) fine sandy loam, common medium faint mottles of brown (10YR 4/3) and grayish brown (10YR 5/2); weak fine and medium granular structure; very friable; soft; common fine roots; strongly acid; abrupt smooth boundary. (0 to 5 inches thick)
Bt1--7 to 16 inches; red (2.5YR 4/6) clay; common medium prominent light brownish gray (10YR 6/2) mottles; moderate medium angular blocky structure; very firm, extremely hard, very plastic and sticky; few 1 to 2 inch pressure faces; few apparent clay films; common fine roots; very strongly acid; gradual smooth boundary. (7 to 15 inches thick)
Bt2--16 to 27 inches; mottled light brownish gray (10YR 6/2), strong brown (7.5YR 5/6) and red (2.5YR 4/6) clay; moderate fine and medium angular blocky structure; very firm, extremely hard, very plastic and sticky; few fine pressure faces; few apparent clay flms; few fine roots; very strongly acid; gradual wavy boundary. (7 to 20 inches thick)
Bt3--27 to 45 inches; mottled pale brown (10YR 6/3), strong brown (7.5YR 5/6), and pale olive (5Y 6/3) clay; moderate fine and medium angular blocky structure; very firm, extremely hard, very plastic and sticky; few fine pressure faces and slickensides; few apparent clay films; few fine roots; very strongly acid; gradual smooth boundary. (7 to 20 inches thick)
BC--45 to 55 inches; pale olive (5Y 6/3) clay, common medium distinct mottles of olive yellow (5Y 6/8); weak fine subangular blocky structure; very firm, extremely hard, plastic; few fine fragments of unconsolidated tuffaceous sandstone; very strongly acid; gradual smooth boundary. (5 to 12 inches thick)
Cr--55 to 65 inches; light gray (2.5Y 7/2) weakly consolidated tuffaceous sandstone; few medium distinct mottles of olive yellow (2.5Y 6/8); massive; very strongly acid.
TYPE LOCATION: Jasper County, Texas; from intersection of U. S. Highway 96 and Texas Highway 63 in Jasper, Texas, 10.1 miles northwest along Texas Highway 63, 3.2 miles north along River Ridge road, 2.4 miles northeast along forest road to intersection, 1.7 miles south and west along forest trail, 50 feet east in forest.
RANGE IN CHARACTERISTICS: Solum thickness and depth to paralithic contact is 40 to 60 inches. Base saturation above the paralithic contact is 35 to 60 percent. The COLE is 0.09 to 0.14 in the Bt horizon.
The combined thickness of the A and E horizon range from 4 to 15 inches. The A horizon has hue of 10YR or 7.5YR, value of 3 to 5, and chroma of 1 to 3. The A and E horizons are loamy fine sand, fine sandy loam, or loam, and range from very strongly acid through medium acid. Where moist values are less than 3.5, the A horizon is less than 6 inches thick. The E, where present, has hue of 10YR or 7.5YR, value of 5 or 6, and chroma of 2 or 3.
The upper part of the Bt horizon has hue of 5YR or 2.5YR, value of 4 or 5, and chroma of 3 to 8. Mottles in shades of brown or gray range from none to few.
The lower part of the Bt horizon and the BC horizon has hue of 10YR to 5Y, value of 5 or 6, and chroma of 2 or 3. Mottles in shades of red and brown range from common to many in the upper part. Mottles in shades of gray, yellow, and brown range from few to common in the lower part. The Bt horizon is clay or silty clay. Clay content of the upper 20 inches averages 40 to 60 percent, but the Bt1 commonly contains up to 70 percent clay. Rection ranges from extremely acid through strongly acid.
The Cr horizon is weakly consolidated tuffaceous siltstone and sandstone that is bentonitic, but contains volcanic ash, volcanic glass, and other pyroclastic material. It ranges from extremely
acid through medium acid.
COMPETING SERIES: These are the Colbert, Etoile, Kipling, Lorman, Oula, Wilcox, and Woodtell series in the same family and Annona, Arriola, Corrigan, Galilee, Kisatchie, Natchitoches, Rosenwall, Spurger, Susquehanna, and Woodville series. Colbert and Oula soils have more yellow hue in the upper part of the B horizon. Etoile soils are less acid, have carbonates at 25 to 50 inches, and are developed from marl. Kipling, Lorman, and Woodtell soils do not have fragments of tuffaceous siltstone in the lower part of the argillic horizon. Natchitoches soils are redder throughout, are in a very fine loam texture family, and contain glauconitic sand in the B and C horizons. Wilcox soils lack an abrupt textural change between the A and B horizons and are underlain by shaly clays at 26 to 58 inches. Annona, Susquehanna, and Woodville soils have sola greater than 60 inches. Arriola soils have mixed mineralogy, thinner sola, and lack vertic properties. Corrigan soils are grayer throughout and have thinner sola. Galilee soils have base saturation of less than 35 percent, Kisatchie soils have sola 20 to 40 inches thick and have grayer upper Bt horizons. Rosenwall soils have base saturation of less than 35 percent. Spurger soils have stratified loamy and sandy C horizons.
GEOGRAPHIC SETTING: Rayburn soils are on gently sloping to moderately steep uplands. Surfaces are mainly plain to convex. Slope gradients range from 1 to 20 percent. The soil formed in acid tuffaceous weakly consolidated siltstone and sandstone. The climate is warm and humid. Average annual precipitation ranges from 44 to 56 inches. The warm season precipitation ranges from 30 to 35 inches. The mean annual temperature ranges from 66 to 70 degrees F., and the Thornthwaite P-E index exceeds 72.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the competing Corrigan and Kisatchie series and the Boykin, Browndell, Kitterll, and Letney series. Boykin and Letney soils have sandy epipedons 20 to 40 inches thick and have loamy control sections. Browndell and Kitterll soils are on associated convex, mid and lower slopes, and have sola less than 20 inches thick. Corrigan soils are on slightly lower plane and concave positions. Kisatchie soils are on similar landscape positions.
DRAINAGE AND PERMEABILITY: Moderately well drained; slow to rapid runof; very slow permeability. A water table is perched above the Bt horizon for a few days following heavy rains. A water table is also perched above the C horizon for some period of time during the cool season of most years
USE AND VEGETATION: Use is for woodland and grazing of livestock. Vegetation is longleaf, shortleaf, and loblolly pines with mixed hardwoods. Understory vegetation includes longleaf uniola, pinehill bluestem, panicum, and threeawn.
DISTRIBUTION AND EXTENT: Southern Coastal Plains of east Texas and possibly Louisiana. The series is of moderate extent.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Temple, Texas
SERIES ESTABLISHED: Newton County, Texas; 1980.