LOCATION KEYESPOINT TN+KY
Established Series
Rev. SEM:RPS:MAV
04/2017
KEYESPOINT SERIES
The Keyespoint series consists of very deep, somewhat poorly drained, very slowly permeable soils that formed in clayey alluvium over loamy alluvium. These soils are on broad, level to undulating, braided flood plains of the lower Mississippi River. Slopes are dominantly 0 to 2 percent but range to 5 percent. The mean annual temperature is 59 degrees F. and mean annual precipitation is 51 inches.
TAXONOMIC CLASS: Clayey over loamy, smectitic over mixed, superactive, nonacid, thermic Vertic Epiaquepts
TYPICAL PEDON: Keyespoint silty clay--cultivated. (Colors are for moist soil.)
Ap--0 to 7 inches; very dark grayish brown (10YR 3/2) silty clay; grayish brown (10YR 5/2) dry; moderate fine granular structure; very hard, very firm, very sticky, very plastic; few fine roots; neutral; abrupt smooth boundary. (3 to 8 inches thick).
Bgl--7 to 18 inches; dark grayish brown (10YR 4/2) silty clay; common fine distinct strong brown (7.5YR 4/6) and dark brown (7.5YR 3/4) mottles and few fine faint dark gray mottles; moderate medium and fine subangular blocky structure; very firm, very plastic, very sticky; few fine roots; common wormholes and casts; shiny faces on some peds; neutral, clear smooth boundary.
Bg2--18 to 30 inches; dark grayish brown (10YR 4/2) clay; common fine faint dark gray (10YR 4/1) and common fine distinct strong brown (7.5YR 4/6) and dark brown (7.5YR 3/4) mottles; moderate medium and fine angular blocky structure; very firm, very plastic, very sticky; few fine roots; common wormholes and casts; shiny faces on many peds; few slickensides; neutral; clear smooth boundary. (Combined thickness of Bg is 17-35 inches).
2C--30 to 62 inches; brown (10YR 5/3) silt loam; many medium faint grayish brown (10YR 5/2) and yellowish brown (10YR 5/4), and common medium distinct brown (7.5YR 4/4) mottles; massive; friable; slightly sticky; non-plastic; few fine roots; common wormholes and casts; slightly alkaline (20 to 35 inches thick).
3C--62 to 72 inches; brown (10YR 5/3) loamy fine sand; single grain; loose; non-sticky; non-plastic; slightly alkaline.
TYPE LOCATION: Lauderdale County, Tennessee; 4.6 miles west of Golddust Church on Crutcher's Lake Road to a field road, 1.5 miles east on the field road to a metal post, 175 feet east of post and 20 feet north of field road.
RANGE IN CHARACTERISTICS: Thickness of the solum ranges from 24 to 38 inches. Depth to a loamy textured layer is 24 to 40 inches. Cracks 1 to 2 cm wide develop to a depth of 50 cm or more in most years.
The A horizon has hue of 10YR, value of 3 or 4 and chroma of 2 or 3. Texture is silty clay, clay, or silty clay loam. Reaction is mildly alkaline to moderately acid.
The Bg horizon commonly has hue of 10YR, value of 4 or 5 and chroma of 2 with few to many mottles in shades of brown, red, or gray. Some pedons have a chroma of 3 above a depth of 20 inches. Texture is silty clay or clay. A few pedons have thin subhorizons of silty clay loam. Structure is moderate or weak subangular blocky or angular blocky. Reaction is mildly alkaline to moderately acid.
The 2C horizon has hue of 10YR, value of 4 to 6 and chroma of 2 or 3 with few to many mottles in shades of brown and gray. Texture is silt loam, loam, very fine sandy loam, fine sandy loam, sandy loam, sandy clay loam, clay loam, or silty clay loam. Some pedons have a 3C horizon with colors like those in the 2C horizon except mottles range from none to common. Texture is loamy fine sand or loamy sand. Reaction of the 2C and 3C horizons is moderately alkaline to moderately acid.
COMPETING SERIES: This is the
Tunica series. Series in closely related families are
Alligator,
Bowdre,
Commerce,
Earle,
Leeper,
Oleno,
Openlake,
Newellton, and
Sharkey. Tunica soils have chroma of less than 2 or have chroma 2 with value of 6 in the upper part of the B horizon. Alligator, Leeper, Openlake,
and
Sharkey soils have a very fine or fine-textured particle-size control section.
Bowdre and
Newellton soils are clayey in the upper 12 to 20 inches over loamy layers, and in addition, Bowdre soils have a mollic epipedon.
Earle and
Oleno soils are in an acid family.
GEOGRAPHIC SETTING: Keyespoint soils are on broad level to undulating braided flood plains of the lower Mississippi River. The slope range is commonly 0 to 2 percent, but ranges to 5 percent. They Keyespoint soils formed in recent clayey alluvium in the upper part and loamy alluvium in the lower part. The mean annual temperature is 59 degrees F. and mean annual precipitation is 51 inches near the type location.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the competing
Bowdre,
Commerce,
Openlake,
Sharkey, and
Tunica series.
DRAINAGE AND PERMEABILITY: Somewhat poorly drained; slow runoff; very slow permeability in the clayey horizons, moderate in the loamy horizons and rapid in sandy horizons where present. This soil is most often flooded during the winter and spring except where protected by levees. Duration of flooding is from a few days to one month. The water table is within 1.0 to 2.0 feet of the surface during the winter and early spring.
USE AND VEGETATION: Most areas of this soil are cultivated with soybeans, corn, and cotton as the principle crops. Some areas are in forest with eastern cottonwood, cherrybark oak, elms, sugarberry, sweetgum, pecan and green ash as some of the dominant species.
DISTRIBUTION AND EXTENT: The Mississippi River flood plain in Arkansas, Kentucky, Louisiana, Mississippi, Missouri, and Tennessee. The series is believed to be moderately extensive. There are approximately 14,000 acres in Lauderdale County, Tennessee.
SOIL SURVEY REGIONAL OFFICE (SSRO) RESPONSIBLE: AUBURN, ALABAMA
SERIES ESTABLISHED: Lauderdale County, Tennessee, 1985.
REMARKS: Keyespoint soils were formerly mapped in the Tunica series. The mineralogy was changed from smectitic to smectitic over mixed in 2002. CE activity class of superactive added in 2002.
Diagnostic horizons and features recognized in this pedon are:
Ochric epipedon--0 to 7 inches (Ap horizon)
Cambic horizon--7 to 30 inches (Bg1 and Bg2 horizons)
Discontinuity and contrasting textural change at a depth of 30 inches.
Laboratory data: Particle size, pH, CEC, and extractable cations were determined for 3 pedons by the University of Tennessee.
National Cooperative Soil Survey
U.S.A.