LOCATION YANCOPIN AR

Established Series
LBW:CH:KC Rev. MAV
11/2018

YANCOPIN SERIES

The Yancopin series consists of very deep, somewhat poorly drained, moderately slowly permeable soils that formed in silty alluvium. These soils are on floodplains of major streams in the Western Lowlands of the Lower Mississippi River Valley; MLRA 131. Slopes range from 0 to 3 percent. Near the type location, the mean annual temperature is about 62 degrees F and the mean annual precipitation is about 51 inches.

TAXONOMIC CLASS: Fine-silty, mixed, superactive, nonacid, thermic Typic Endoaquepts

TYPICAL PEDON: Yancopin silty clay loam-1 percent slope, idle field. (Colors are for moist soil unless otherwise stated.)

Ap--0 to 4 inches; dark grayish brown (10YR 4/2) silty clay loam; moderate medium granular structure grading to weak fine subangular blocky structure in the lower part; firm; many fine and medium roots; many medium and coarse pores; few fine and medium round brown-black iron-manganese concretions; slightly acid; clear smooth boundary. (3 to 10 inches thick)

Bg1--4 to 40 inches; dark grayish brown (10YR 4/2) silty clay loam; moderate medium subangular blocky structure; firm; few fine roots; common medium and coarse pores; common worm holes; few charcoal fragments; common coarse faint brown (10YR 4/3) and dark yellowish brown (10YR 4/4) and few medium distinct yellowish brown (10YR 5/4) iron accumulations throughout matrix; common medium and coarse round brown-black iron-manganese concretions; few medium distinct black (10YR 2/1) manganese accumulations on faces of some peds; slightly acid; gradual wavy boundary.

Bg2--40 to 56 inches; dark grayish brown (10YR 4/2) silty clay loam; weak medium subangular blocky structure; firm; few fine roots; common fine medium and coarse pores; many medium faint dark yellowish brown (10YR 4/4) and brown (10YR 4/3) and common medium distinct yellowish brown (10YR 5/4) iron accumulations throughout matrix; common medium and coarse round brown-black iron-manganese concretions; few medium prominent black (10YR 2/1) manganese accumulations on faces of some peds; neutral; gradual smooth boundary. (Combined thickness of the Bg horizon ranges 25 to 56 inches.)

BC--56 to 76 inches; light brownish gray (10YR 6/2) silty clay loam; weak medium subangular blocky structure; firm; common fine, medium and coarse pores; many medium distinct brown (10YR 4/3) and dark yellowish brown (10YR 4/4) and common medium distinct yellowish brown (10YR 5/4) iron accumulations throughout matrix; common medium and coarse round brown-black iron-manganese concretions; few medium prominent black (10YR 2/1) manganese accumulations on faces of some peds; neutral.

TYPE LOCATION: Woodruff County, Arkansas; NW/4SW4NW1/4 sec. 36, T. 8 N., R. 4 W.

RANGE IN CHARACTERISTICS: Solum thickness ranges from 45 to more than 60 inches. The 10 to 40 inch control section contains less than 10 percent sand, 25 to 35 percent clay and 55 to 65 percent silt. Reaction ranges from moderately acid to neutral in the A, B, and BC horizons and moderately acid to slightly alkaline in the C horizon.

The A or Ap horizon has hue of 10YR, value of 4 or 5 and chroma of 2 or 3. Redox accumulations and depletions range from none to common in shades of brown or gray. Texture is silt loam or silty clay loam.

The Bg horizon has hue of 10YR or 2.5Y, value of 4 or 5, and chroma of 2. Redox accumulations and depletions are in shades of brown or gray. Texture is silt loam or silty clay loam.

The BC or BCg horizon has hue of 10YR or 2.5Y, value of 4 to 6, and chroma of 1 to 3. Redox accumulations and depletions are in shades of brown or gray. Texture is silt loam, silty clay loam or loam.

Some pedons have C or Cg horizons that have hue of 10YR or 2.5Y, value of 4 to 6, and chroma of 1 to 4. Redox accumulations and depletions are in shades of gray or brown. Texture is silt loam, silty clay loam, loam, very fine sandy loam, fine sandy loam, sandy loam, loamy fine sand or loamy very fine sand.

COMPETING SERIES: There are no other series in this family.

GEOGRAPHIC SETTING: Yancopin soils occur on level to undulating floodplains of the Cache River, White River, St. Francis River and other major streams in the Western Lowlands and St. Francis Basin of the Lower Mississippi River Valley. These soils formed in Holocene aged alluvium, high in silt. Slopes range from 0 to 3 percent. The mean annual temperature ranges from about 60 to 65 degrees F and the mean annual precipitation ranges from about 48 to 54 inches.

GEOGRAPHICALLY ASSOCIATED SOILS: These include: Kobel, Taylorbay, Tipp soils. Kobel soils are on slightly lower positions on the floodplain. They are poorly drained and in a fine particle-size class. Taylorbay soils are on higher positions on the floodplain. They are well drained and have a thick mollic epipedon. Tipp soils are on slightly higher positions on the floodplain. They are moderately well drained and have a thick mollic epipedon.

DRAINAGE AND PERMEABILITY: Somewhat poorly drained; Negligible to low runoff and moderately slowly permeable. Most areas of this soil commonly flood a few times each year, for brief to very long periods, usually during winter and early spring. Levees protect some areas. A seasonally high water table is within 1 to 2 feet of the soil surface from December through April, most years.

USE AND VEGETATION: Most areas are cultivated. The major crops are soybeans, grain sorghum and rice. Minor areas are still in woodland of bottomland hardwoods.

DISTRIBUTION AND EXTENT: Lower Mississippi River Valley of Arkansas and possibly Missouri; MLRA 131. The series is of moderate extent.

SOIL SURVEY REGIONAL OFFICE (SSRO) RESPONSIBLE: AUBURN, ALABAMA

SERIES ESTABLISHED: Woodruff County, Arkansas; 1992.

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

Ochric epipedon - The zone from the surface to a depth of 4 inches (Ap horizon).

Cambic horizon - The zone from 4 to 76 inches which includes the Bg1, Bg2 and BC horizons.

These soils were formerly classified Aeric Fluvaqents because they contain more than .2 percent organic carbon at 125 cm below the soil surface. The organic carbon criteria was dropped in the 1998 Keys To Soil Taxonomy. As a result of this change, the classification of Yancopin was changed to Typic Endoaquepts.

ADDITIONAL DATA: Characterization of the type location by the University of Arkansas Soil Characterization Laboratory. Pedon No. S91AR-147-06. Additional data on pedons S92AR-145-01 and S92AR-147-01.

National Cooperative Soil Survey
U.S.A.