LOCATION JACKPORT AR+MO

Established Series
Rev. LBW
10/2018

JACKPORT SERIES

The Jackport series consists of very deep, poorly drained, very slowly permeable soils that formed in clayey alluvium. These level to nearly level soils are on Pleistocene terraces in the lower Mississippi Valley. Slopes range from 0 to 3 percent.

TAXONOMIC CLASS: Fine, smectitic, thermic Chromic Epiaquerts

TYPICAL PEDON: Jackport silty clay loam, 1 percent slopes, cultivated. (Colors are for moist soil unless otherwise stated.)

Ap--0 to 5 inches; dark gray (10YR 4/1) silty clay loam; weak fine subangular blocky structure; firm; common medium roots; slightly acid; abrupt wavy boundary. (3 to 10 inches thick)

Bg--5 to 11 inches; grayish brown (10YR 5/2) silty clay; moderate medium subangular blocky structure; firm; common medium roots; shiny pressure faces on peds; strongly acid; clear smooth boundary. (0 to 12 inches thick)

Bssg1--11 to 24 inches; grayish brown (2.5Y 5/2) silty clay; moderate medium and fine blocky structure; very firm; few medium roots; few slickensides; shiny pressure faces on peds; common medium distinct yellowish red (5YR 4/6) and strong brown (7.5YR 5/6) iron accumulations in matrix; few fine black (N 2/0) cemented manganese concretions; very strongly acid; clear smooth boundary.

Bssg2--24 to 38 inches; grayish brown (2.5Y 5/2) silty clay; strong medium and coarse blocky structure; very firm; few fine roots; few slickensides; shiny pressure faces on peds; few fine black (N 2/0) cemented manganese concretions; few fine faint yellowish brown iron accumulations; neutral; gradual wavy boundary.

Bssg3--38 to 50 inches; olive gray (5Y 5/2) silty clay; strong coarse blocky structure; very firm; few slickensides; shiny pressure faces on peds; common fine distinct dark yellowish brown (10YR 4/6) iron accumulations; few medium pockets and seams of carbonates; neutral; clear wavy boundary. (Combined thickness of the Bssg horizon ranges from 20 to 40 inches.)

B'g--50 to 62 inches; olive gray (5Y 5/2) silty clay loam; moderate medium subangular blocky structure; firm; shiny pressure faces on peds; common fine distinct dark yellowish brown (10YR 4/4) iron accumulations; few medium pockets and seams of carbonates; slightly alkaline; clear wavy boundary. (0 to 15 inches thick)

BC--62 to 80 inches; grayish brown (2.5Y 5/2) clay loam; weak medium subangular blocky structure; friable; common medium distinct yellowish brown (10YR 5/4) iron accumulations; few medium carbonate concretions; moderately alkaline.

TYPE LOCATION: Jackson County, Arkansas; 2 miles southwest of Beedeville on Arkansas Highway 37; then 2000 feet east on Highway 42; then 100 feet south of highway; NE1/4NW1/4NW/4, sec. 20, T. 9 N., R. 1 W.

RANGE IN CHARACTERISTICS: Solum thickness ranges from 50 to more than 72 inches. Cracks 1-3 cm wide extend from the surface to depths of 20 to 40 inches during dry periods. Clay content of the 10 to 40 inch control section, typically ranges from 50 to 60 percent. Reaction ranges from very strongly acid to slightly acid in the A horizon and is very strongly acid or strongly acid in the Bg and upper Bssg and moderately acid to slightly alkaline in the lower Bssg and B'g horizons and slightly acid to moderately alkaline in the BCg and C horizons.

The Ap has hue of 10YR, value of 4 or 5 and chroma of 1 or 2. Iron accumulations are in shades of brown. Texture is silty clay loam, silty clay or clay.

The Bg and Bssg horizons have hue of 10YR, 2.5Y or 5Y, value of 4 to 6, and chroma of 1 or 2. Iron accumulations and depletions are in shades in red, brown and gray. Texture is clay, silty clay and silty clay loam in the lower part.

The B'g and BCg horizons have hue of 10YR, 2.5Y, or 5Y, value of 4 to 6, and chroma of 1 or 2. Iron accumulations and depletions are in shades of gray or brown. Texture is silty clay, silty clay loam, or clay loam.

The C horizon, if present, has hue of 10YR, 2.5Y, or 5Y, value of 4 to 6, and chroma of 1 or 2. Iron accumulations and depletions are in shades of gray or brown. Texture is variable, but dominantly silt loam, silty clay loam, or silty clay.

COMPETING SERIES: Sucarnoochee is the only other series in the family. Sucarnoochee soils occur on flood plains in the Blackland Prairie; MLRA 135. They are neutral to moderately alkaline throughout and somewhat poorly drained.

GEOGRAPHIC SETTING: Jackport soils are on Pleistocene terraces in the Western Lowlands and St. Francis Basin of the lower Mississippi Valley; MLRA 131. Slopes range from 0 to 3 percent. These soils formed in clayey alluvium. The mean annual precipitation is about 50 inches and the mean annual temperature is about 61 degrees F. near the type location.

GEOGRAPHICALLY ASSOCIATED SOILS: These include the Amagon, Foley, Grubbs and Overcup series. Amagon soils occur on lower terraces and contain less clay and do not have vertic properties. Foley soils occur on similar landscapes and contain less clay and have a natric horizon. Grubbs soils occur on the margin of higher terraces and on escarpments between terraces and are better drained, contain less clay and do not have vertic properties. Overcup soils occur on similar landscapes and have an abrupt texture change between the ochric epipedon and an underlying argillic horizon.

DRAINAGE AND PERMEABILITY: Poorly drained; runoff is negligible to high depending on slope; very slow permeability. A perched seasonally high water table is within 12 inches of the soil surface during winter and spring.

USE AND VEGETATION: Most areas are cultivated. Dominant crops are rice, soybeans, and grain sorghum. Minor areas are in woodland of oaks, gums, hickory, and ash.

DISTRIBUTION AND EXTENT: Western Lowlands and St. Francis Basin of Arkansas and Missouri, and possibly similar areas in Louisiana and Mississippi. The series is of large extent.

MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: AUBURN, ALABAMA

SERIES ESTABLISHED: Jackson County, Arkansas; 1971.

REMARKS: Diagnostic horizons and features recognized in this pedon are:

Ochric epipedon - The zone from the surface to a depth of 5 inches.

Cambic horizon - The zone from 5 to 80 inches.

Slickensides - the zone from 11 to 50 inches.

ADDITIONAL DATA: Characterization of the type location by the University of Arkansas soil characterization laboratory. Pedon No. S78AR-067-1. Additional data by the National Soil Survey Laboratory. Pedon No. 84P550

National Cooperative Soil Survey
U.S.A.