LOCATION CADDO LA+AREstablished Series
TAXONOMIC CLASS: Fine-silty, siliceous, active, thermic Typic Glossaqualfs
TYPICAL PEDON: Caddo silt loam--slash pine woodland. (Colors are for moist soil unless otherwise stated.)
A--0 to 6 inches; grayish brown (10YR 5/2) silt loam; common fine faint light brownish gray (10YR 6/2) and common fine distinct brownish yellow (10YR 6/6) mottles; weak fine subangular blocky structure; friable; few medium black concretions; strongly acid; abrupt irregular boundary. (2 to 8 inches thick)
Eg1--6 to 16 inches; light brownish gray (10YR 6/2) silt loam; many medium distinct brownish yellow (10YR 6/6) mottles; weak fine subangular blocky structure; friable; few fine tubular pores; strongly acid; gradual smooth boundary. (6 to 24 inches thick)
Eg2--16 to 30 inches; light brownish gray (10YR 6/2) silt loam; common fine prominent strong brown (7.5YR 5/6) mottles; weak medium subangular blocky structure; friable; few fine red concretions; strongly acid; abrupt irregular boundary. (5 to 14 inches thick)
Btg/E--30 to 60 inches; light brownish gray (10YR 6/2) silty clay loam (Btg); many medium prominent strong brown (7.5YR 5/6) and red (2.5YR 4/8) mottles; weak medium subangular blocky structure; firm; thin clay films on peds; tongues of silt loam (E) 2 to 10 cm wide extending to 45 inches make up about 20 percent of horizon; about 4 percent medium red concretions and plinthite; strongly acid; clear irregular boundary. (8 to 40 inches thick)
Btg--60 to 87 inches; light gray (10YR 7/1) silty clay loam; many coarse and fine distinct yellow (10YR 7/6) and yellowish brown (10YR 5/8) mottles; weak medium subangular blocky structure; firm; strongly acid.
TYPE LOCATION: Beauregard Parish, Louisiana; 1 mile north of Hollinsworth on U. S. Highway 171; 0.5 mile east on access road; 150 feet north of road opposite east edge of gasoline plant; NW1/4NE1/4, sec. 19, T. 6. S., R. 8 W.
RANGE IN CHARACTERISTICS: Solum thickness ranges from about 60 to 100 inches. Total thickness of the A horizon is 15 to 35 inches and tongues of the A2 horizon extend into the B horizon.
The A horizon has hue of 10YR, value of 4 or 5, and chroma of 1 or 2. Texture is silt loam, loam, or very fine sandy loam. Reaction ranges from very strongly acid to medium acid.
The Eg horizon has hue of 10YR or 2.5Y, value of 5 or 6, and chroma of 1 or 2 with common to many mottles in shades of brown or yellow. Texture is silt loam, loam, or very fine sandy loam. Reaction ranges from very strongly acid to medium acid.
The Btg horizon has hue of 10YR or 2.5Y, value of 5 to 7, and chroma of 1 or 2. Mottles in shades of yellow, brown, or red range from common to many. Texture is loam, silt loam, or silty clay loam. Reaction ranges from very strongly acid to medium acid. The Btg horizon has 1 to 5 percent plinthite in some subhorizons. The upper 20 inches of the Btg horizon averages 10 percent or more sand and 20 to 35 percent clay.
The C horizon, where present, is mottled in shades of gray, yellow, brown, or red. Texture is loam, silt loam, or silty clay loam. Reaction ranges from strongly acid to medium acid.
COMPETING SERIES: These are the Alikchi, Guyton, and Kinder soils in the same family and the Amy, Basile, Calhoun, Fountain, Frost, Wrightsville, and Zachary series. Alikchi soils have bedrock within a depth of 20 to 40 inches. Amy and Zachary soils do not have an E horizon that tongues into the B horizon. In addition, Zachary soils have an abrupt change in texture from the A to the B horizon and have mixed mineralogy. Basile soils do not have red mottles and are more alkaline. Calhoun soils contain less than 10 percent sand. Fountain soils have a B horizon that is mildly alkaline or moderately alkaline and contains less than 5 percent sand. Frost, Guyton, and Kinder soils do not have plinthite. Wrightsville soils have fine-textures in the Bt horizon.
GEOGRAPHIC SETTING: Caddo soils are on nearly level to very gently sloping terraces of mid to late Pleistocene age. Circular mounds 50 to 75 feet in diameter and 15 to 30 inches high are common in certain areas but many of them have been leveled. The soil formed in thick beds of unconsolidated loamy material. The climate is warm and humid. Mean annual temperature ranges from 60 to 70 degrees F. Average annual precipitation ranges from 42 to 62 inches.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the competing Guyton soils and the Beauregard, Glenmora, Messer, and Wrightsville soils. Beauregard soils are on higher landscapes, are not as gray, and contain more than 5 percent plinthite. Glenmora soils are on more sloping positions and are not as gray. Guyton soils are in slightly more concave positions. Messer soils are on nearby circular mounds and have a thick silt loam Bw horizon. Wrightsville soils are on similar landscapes and have a fine-textured argillic horizon.
DRAINAGE AND PERMEABILITY: Poorly drained; slow runoff; slow permeability.
USE AND VEGETATION: Principally in woodland; much of which is grazed.
DISTRIBUTION AND EXTENT: Western Louisiana, eastern Texas, and southern Arkansas. The soil is extensive.
MLRA OFFICE RESPONSIBLE: Temple, Texas
SERIES ESTABLISHED: Caddo Parish, Louisiana; 1906.
REMARKS: Diagnostic horizons and features recognized in this pedon are:
Ochric epipedon........................0 to 30 inches (A,Eg1,Eg2)
Argillic horizon...30 to 87+ inches (Btg part of Btg/E & Btg)
Glossic feature.......................30 to 60 inches (Btg/E)
Albic horizon..........................6 to 30 inches (Eg1,Eg2)