LOCATION ROBINSONVILLE MS+AR KY LA OK TN TXEstablished Series
TAXONOMIC CLASS: Coarse-loamy, mixed, superactive, nonacid, thermic Typic Udifluvents
TYPICAL PEDON: Robinsonville very fine sandy loam - forest. (Colors are for moist soil unless otherwise stated.)
A--0 to 7 inches; dark grayish brown (10YR 4/2) very fine sandy loam; weak fine granular structure; very friable; neutral; abrupt smooth boundary. (4 to 10 inches thick)
C1--7 to 20 inches; brown (10YR 5/3) fine sandy loam; massive; very friable; few silt loam strata 1 to 4 mm. thick; neutral; clear smooth boundary.
C2--20 to 24 inches; brown (10YR 4/3) loamy very fine sand; single grained; very friable; thin strata 1 to 5 mm. thick of very dark gray (10YR 3/1) silt loam; slightly alkaline; gradual smooth boundary.
C3--24 to 46 inches; brown (10YR 5/3) fine sandy loam; massive; very friable; thin layers less than 2.5 mm. thick of dark grayish brown (10YR 4/2) silt loam; moderately alkaline; gradual smooth boundary.
C4--46 to 70 inches; dark grayish brown (10YR 4/2) loamy very fine sand; single grained; loose; thin bedding planes; neutral.
TYPE LOCATION: Adams County, Mississippi; 2.0 miles south of Anna, on gravel road, 2.3 miles west and northwest on oil field gravel road and 0.8 mile west on pipeline right-of-way; sec. 38, T. 9 N., R. 3 W.
RANGE IN CHARACTERISTICS: The 10- to 40-inch control section has 5 to 18 percent clay.
The A horizon has hue of 10YR, value of 3 to 5, and chroma 2 to 4. The horizon is less than 6 inches thick if the color value is less than 3.5. It is very fine sandy loam, silt loam, fine sandy loam, or loam. An overwash phase is also recognized for areas where a recent cap of clayey alluvium ranges from 8 to less than 20 inches thick. Reaction ranges from slightly acid to moderately alkaline.
The C horizon has hue of 10YR, value of 4, and chroma of 2 to 4; or value of 5 or 6, and chroma of 3 or 4. Iron depletions having chroma of 2 or less, if present, are below a depth of 20 inches. The C horizon is stratified fine sandy loam, silt loam, loam, very fine sandy loam, loamy very fine sand, or loamy fine sand. The strata vary in thickness and arrangement within short distances. Some pedons have a buried soil below a depth of 20 inches. A clayey substratum with texture of silty clay loam or silty clay may be present below a depth of 50 inches in some pedons where land leveling operations have removed a foot or more of surface soil. Reaction ranges from slightly acid to moderately alkaline.
COMPETING SERIES: These are no other series in this family.
GEOGRAPHIC SETTING: Robinsonville soils are on the flood plain of the Mississippi River; MLRA 131. They are in natural levee positions along the current and former channels of the river. Slopes range from 0 to 5 percent. The climate is warm and humid. Near the type location mean annual precipitation is 55.0 inches and mean annual temperature is 67 degrees Fahrenheit.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the Bruno, Bruin, Commerce, Convent, and crevasse soils. The excessively drained Bruno soils are on slightly higher positions on the natural levees and are sandy in the control section. The moderately well drained Bruin soils are on similar positions on the landscape, and have layers that are seasonally wet within a depth of 40 inches, and are coarse-silty in the particle-size control section. The somewhat poorly drained Commerce soils are on slightly lower positions on the natural levee, and have a cambic horizon with a matrix that has chroma of 2 or less, and a fine-silty particle-size class. The somewhat poorly drained Convent soils are on lower positions on the natural levee, and have a dominent chroma of 2 or less in the C horizon, and are coarse-silty in the particle-size class. Excessively drained Crevasse soils are on crevasse splays and point bars, and have a sandy control section, and do not have strata of finer textured material within a depth of 40 inches,.
DRAINAGE AND PERMEABILITY: Well drained; slow to medium runoff; moderate to moderately rapid permeability. Most areas of this soil are subject to flooding unless protected. Frequency is none to common and duration is brief to long. The water table fluctuates between about 4 to 6 feet during high rainfall periods of January through April.
USE AND VEGETATION: Most areas of the Robinsonville soils are cleared and used for growing cotton, corn, soybeans, hay, and pasture. Wooded areas are in mixed hardwoods, principally sycamore, sweetgum, hackberry, cottonwood, pecan, and elm.
DISTRIBUTION AND EXTENT: Alabama, Arkansas, Kentucky, Louisiana, Mississippi, Missouri, and Tennessee. The series is of moderate extent.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Auburn, Alabama
SERIES ESTABLISHED: Tunica County, Mississippi; 1949.
REMARKS: The series was updated in 2004 to recognize clayey substratum layers below a depth of 50 inches in land leveled areas. Diagnostic horizons and features recognized in the type location pedon include:
Ochric epipedon - the zone from the surface of the soil to a depth of approximately 7 inches (A horizon).
Irregular organic carbon distribution - 0 to 50 inches deep (A and C horizons).