LOCATION CATALPA MS+AL AREstablished Series
TAXONOMIC CLASS: Fine, smectitic, thermic Fluvaquentic Hapludolls
TYPICAL PEDON: Catalpa silty clay loam, occasionally flooded, in cultivated field.
(Colors are for moist soil unless otherwise stated.)
Ap--0 to 6 inches; very dark grayish brown (2.5Y 3/2) silty clay loam; moderate fine and medium granular structure, some platiness in lower 2 inches; firm, sticky, plastic; few fine roots; mildly alkaline; abrupt smooth boundary.
A--6 to 20 inches; very dark grayish brown (2.5Y 3/2) silty clay; weak coarse prismatic structure parting to moderate medium subangular blocky and angular blocky; firm, sticky, plastic; few fine roots; shiny stress surfaces on peds; few fine pieces charcoal; moderately alkaline; clear wavy boundary. (Combined thickness of the A horizon is 10 to 24 inches)
Bw1--20 to 27 inches; dark grayish brown (2.5Y 4/2) silty clay; common fine faint olive brown (2.5Y 4/4) mottles; weak coarse prismatic structure parting to moderate and strong fine and medium angular blocky and subangular blocky; firm, very sticky, very plastic; stress surfaces on faces of peds; few fine brown and black concretions; few fine lime concretions; slightly effervescent; moderately alkaline; gradual wavy boundary.
Bw2--27 to 41 inches; mottled olive brown (2.5Y 4/4) and dark grayish brown (2.5Y 4/2) silty clay; weak coarse prismatic structure parting to moderate fine and medium angular blocky and subangular blocky; firm, sticky, very plastic; shiny stress surfaces on faces of peds; few fine brown and black concretions; few pieces charcoal; slightly effervescent; moderately alkaline; gradual wavy boundary.
Bw3--41 to 54 inches; mottled dark grayish brown (2.5Y 4/2), and olive brown (2.5Y 4/4) silty clay; moderate medium angular blocky structure; firm, sticky, very plastic; shiny stress surfaces on faces of peds; few fine brown and black concretions; few medium lime concretions; mildly effervescent; moderately alkaline; gradual wavy boundary. (Combined thickness of the Bw horizons is 25 to 55 inches thick)
BC--54 to 60 inches; mottled dark grayish brown (2.5Y 4/2), olive brown (2.5Y 4/4), and yellowish brown (10YR 5/6) silty clay; weak fine angular blocky structure; firm, sticky, very plastic; shiny stress surfaces on faces of peds; few fine brown and black concretions; few medium lime concretions; mildly effervescent; moderately alkaline.
TYPE LOCATION: Lee County, Mississippi; 5 miles west of Shannon, 770 feet east and 100 feet north of SW corner, SW1/4SW1/4 sec. 17, T. 11 S., R. 5 E.
RANGE IN CHARACTERISTICS: Thickness of the solum exceeds 60 inches. The soil ranges from slightly acid to moderately alkaline. Some pedons are noncalcareous throughout.
The A horizon has hue of 7.5YR, 10YR, 2.5Y, or 5Y; value of 2 or 3; and chroma of 1 to 3; or it is neutral with value of 2 or 3, and chroma of 0. It is silty clay loam, silty clay, or clay. Some pedons have an overwash of coarser materials that is less than 10 inches thick in areas along stream channels.
The upper part of the Bw horizon has hue of 10YR or 2.5Y, value of 4, and chroma of 2, or it is mottled in shades of brown and gray. The lower part of the Bw horizon is mottled in shades of brown and gray. The Bw horizon is silty clay loam, silty clay, or clay. Lime concretions or brown and black concretions or both, if present, are few to common.
The BC horizon is mottled in shades of brown, gray, yellow, or olive. Texture is clay, silty clay, or silty clay loam. Lime concretions or brown and black concretions or both, if present, are few to common.
COMPETING SERIES: There are no competing series in the same family. Closely related soils are the Belden, Bowdre, Griffith, Houlka, Kaufman, Leeper, Lynnville, Marietta, Trinity, Tuscumbia, and Una series. Belden, Houlka, Leeper, Marietta, Tuscumbia, and Una soils do not have a mollic epipedon. Lynnville soils have a fine-silty control section. Bowdre soils have a clayey over loamy particle size class. Houlka and Una soils are acid in the control section. Griffith, Kaufman and Trinity soils have a thicker A horizon, have grayer colors, and have intersecting slickensides within the control section.
GEOGRAPHIC SETTING: Catalpa soils are on flood plains or low terraces along streams that drain the Blackland Prairie Major Land Resource Area. These nearly level to gently sloping soils formed in clayey alluvial sediments. Slopes range from 0 to 3 percent. Mean annual precipitation is 51 inches, and mean annual temperature is 63 degress Fahrenheit near the type location.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the Belden, Griffith, Houlka, Leeper, Marietta, Tuscumbia, and Una soils of the competing series. These are soils across the nearly lineral surfaces of flood plains and they formed in clayey alluvium derived from uplands of the Blackland Prairie Major Land Resource Area. Somewhat poorly drained Belden, Houlka, and Leeper soils are on broad, nearly level surfaces. Moderately well drained Griffith and Marietta soils are on slightly higher positions. Poorly drained Tuscumbia and Una soils, which commonly are in low areas and sloughs, typically have a slightly concave surface.
DRAINAGE AND PERMEABILITY: Somewhat poorly to moderately well drained; slow permeability. The water table is at a depth of 1.5 to 2.0 feet during wet seasons late in winter and early in spring. These soils are subject to either occasional or frequent flooding for brief duration late in winter and early in spring.
USE AND VEGETATION: Most areas of these soils have been cleared and are used for growing pasture, hay, and row crops such as cotton, corn, and soybeans. Wooded areas are in mixed hardwoods.
DISTRIBUTION AND EXTENT: Alabama, Arkansas, Mississippi, and Texas. The series is of moderate extent.
MLRA OFFICE RESPONSIBLE: Auburn, Alabama
SERIES ESTABLISHED: Oktibbeha County, Mississippi; 1907.
REMARKS: Diagnostic horizons and features recognized in this pedon are:
Mollic epipedon - the zone from the surface to a depth of about 20 inches (Ap, A horizons).
Cambic horizon - the zone from approximately 20 to 60 inches (Bw1, Bw2, Bw3, BC horizons).
ADDITIONAL DATA - Engineering test data for the typical profile are published in the Soil Survey of Lee County, Mississippi (issued March 1973) pp. 54-55.