LOCATION GORHAM ILEstablished Series
TAXONOMIC CLASS: Fine-silty, mixed, superactive, mesic Fluvaquentic Endoaquolls
TYPICAL PEDON: Gorham silty clay loam - on a nearly level flood plain in a cultivated field at an elevation of about 360 feet above mean sea level. (Colors are for moist soil unless otherwise noted.)
Ap--0 to 7 inches; very dark gray (10YR 3/1) silty clay loam, grayish brown (10YR 5/2) dry; moderate fine and medium angular blocky structure parting to weak fine granular; firm; common very fine roots; neutral; abrupt smooth boundary.
A--7 to 14 inches; black (10YR 2/1) silty clay loam, dark gray (10YR 4/1) dry; moderate fine and medium angular blocky structure; very firm; common very fine roots; common faint black (10YR 2/1) organic coatings on faces of peds; few fine irregular brown (7.5YR 4/4) masses of iron-manganese accumulation with sharp boundaries; neutral; clear smooth boundary. (Combined thickness of the Ap and A horizons is 10 to 18 inches)
Btg1--14 to 26 inches; dark gray (10YR 4/1) silty clay loam; weak medium prismatic structure parting to moderate fine and medium angular blocky; very firm; common very fine roots; common faint very dark gray (10YR 3/1) organo-clay films on faces of peds; common fine distinct dark yellowish brown (10YR 4/4) masses of iron accumulation in the matrix; common fine irregular brown (7.5YR 4/4) masses of iron-manganese accumulation with clear boundaries; neutral; gradual smooth boundary.
Btg2--26 to 36 inches; dark grayish brown (2.5Y 4/2) silty clay loam; moderate medium prismatic structure parting to moderate medium angular blocky; very firm; few very fine roots; many distinct very dark grayish brown (10YR 3/2) organo-clay films on faces of peds; many fine prominent dark yellowish brown (10YR 4/4) masses of iron accumulation in the matrix; common fine irregular brown (7.5YR 4/4) masses of iron-manganese accumulation with clear boundaries; about 12 percent sand; slightly acid; clear smooth boundary. (Combined thickness of the Btg or Bg horizons is 14 to 22 inches)
2Bt1--36 to 47 inches; olive brown (2.5Y 4/3) clay loam; moderate medium prismatic structure parting to moderate fine and medium angular blocky; firm; few very fine roots; few very fine continuous tubular pores; common distinct very dark grayish brown (10YR 3/2) organo-clay films on faces of peds and few prominent very dark gray (10YR 3/1) organo-clay films on vertical faces of peds and lining root channels; many medium faint grayish brown (2.5Y 5/2) iron depletions in the matrix; neutral; clear smooth boundary.
2Bt2--47 to 54 inches; olive brown (2.5Y 4/3) loam; weak medium angular blocky structure; friable; few very fine roots; few very fine continuous tubular pores; common distinct very dark grayish brown (10YR 3/2) organo-clay films on faces of peds and lining root channels; common fine faint dark grayish brown (2.5YR 4/2) iron depletions and few medium distinct dark yellowish brown (10YR 4/4) masses of iron accumulation in the matrix; slightly acid; clear smooth boundary. (Combined thickness of the 2B horizons is 12 to 22 inches)
2BC--54 to 62 inches; brown (10YR 4/3) fine sandy loam; weak medium and coarse angular blocky structure; very friable; few very fine roots; common very fine and fine continuous tubular pores; few distinct very dark grayish brown (10YR 3/2) organo-clay films on vertical faces of peds and lining root channels and pores; common medium distinct dark grayish brown (2.5Y 4/2) iron depletions in the matrix; few shiny mica flecks; slightly acid; clear smooth boundary. (0 to 10 inches)
2C1--62 to 78 inches; brown (10YR 4/3) stratified fine sandy loam and loamy fine sand; massive; very friable; few very fine and fine continuous tubular pores; common fine distinct grayish brown (2.5Y 5/2) iron depletions in the matrix; few shiny mica flecks; slightly acid; abrupt smooth boundary.
2C2--78 to 90 inches; yellowish brown (10YR 5/4) fine sand; single grain; loose; neutral.
TYPE LOCATION: Jackson County, Illinois; about 1 mile northwest of Gorham; approximately 1,800 feet north and 1,400 feet east of the southwest corner of sec. 24, T.9 S., R. 4 W.; USGS Altenburg, MO.-IL. topographic quadrangle; lat. 37 degrees 43 minutes 37 seconds N. and long. 89 degrees 30 minutes 12 seconds W.
RANGE IN CHARACTERISTICS: The depth to the base of soil development ranges from 36 to 72 inches. Thickness of the mollic epipedon ranges from 10 to 24 inches, and extends into the upper part of the B horizon in some pedons. Rock fragment content averages less than 5 percent by volume throughout the series control section. In the particle-size control section, clay content averages 27 to 35 percent and average sand content coarser than very fine is less than 15 percent. Reaction is slightly acid to slightly alkaline. Some pedons contains carbonates below a depth of 40 inches.
The upper part of the series control section (Ap and A) has hue of 10YR, value of 2 or 3 (4 or 5 dry) and chroma of 1 or 2. The lower part of the A horizon in some pedons has distinct or prominent redoximorphic masses of iron accumulation in the matrix. Texture is silty clay loam, and less commonly silt loam or silty clay. Clay content averages 27 to 35 percent, but ranges from 20 to 42 percent clay, and sand content coarser than very fine is less than 15 percent.
The second part of the series control section (Btg or Bg horizons that formed in silty alluvium) has hue of 10YR, 2.5Y, 5Y, or is neutral; value of 3 to 5; and chroma of 0 to 2. Texture is silty clay loam or silty clay. Clay content averages 27 to 35 percent, but individual subhorizons range to 42 percent clay. Sand content coarser than very fine is less than 15 percent.
The third part of the series control section (2Bt, 2Btg, 2Bg, 2Bw or 2BC horizons that formed in loamy or sandy alluvium) has hue of 7.5YR, 10YR, 2.5Y, or 5Y; value of 3 to 5; and chroma of 1 to 4. Texture is sandy clay loam, clay loam, loam, sandy loam, or loamy sand, and the fine and very fine analogs. Clay content averages 22 to 30 percent and sand content ranges from 35 to 70 percent. Individual horizons or strata range from 8 to 32 percent clay and from 30 to 85 percent sand.
The lower part of the series control section (2C or 2Cg) has hue of 10YR, 2.5Y, or 5Y; value of 4 to 6; and chroma of 2 to 6. Texture is sand, loamy sand, and less commonly sandy loam, and the fine and very fine analogs. Thin strata of other textures are in some pedons. Clay content averages 5 to 15 percent and sand content averages 60 to 95 percent.
COMPETING SERIES: These are Beaucoup, Blackoar, Bridgeson, Copperas, Ettrick, Leshara, Lummi, Sauvie, Sepo and Wapato soils. Beaucoup and Sepo soils average less than 40 percent sand in the lower one-half of the series control section. Blackoar, Ettrick, Leshara and Lummi soils average less than 27 percent clay in the particle-size control section. Bridgeson, Sauvie, and Wapato soils are dominated by amorphous clays inherited from volcanic ash. Copperas soils have a paralithic contact within a depth of 40 to 60 inches.
GEOGRAPHIC SETTING: Gorham soils are on nearly level or gently undulating flood plains of major rivers. Slopes are typically 0 to 3 percent, but range to 7 percent. These soils formed in silty or loamy alluvium at least 40 inches thick. Below a depth of 40 inches the alluvium increases in sand content and decreases in clay content. These soils typically are subject to frequent flooding, but some areas are rare or occasional because of levees, locks and dams, or other flood-control structures. Mean annual temperature is 54 to 57 degrees F., mean annual precipitation is 36 to 44 inches, frost-free period is 180 to 210 days, and elevation is 340 to 450 feet above sea level.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the Ambraw, Beaucoup, Darwin, Fults, Nameoki, and Shaffton soils. The poorly drained Ambraw and Beaucoup soils are on similar adjacent parts of the flood plain. The poorly drained Darwin and Fults soils have more than 35 percent clay in the control section and are on lower parts of the flood plain. The somewhat poorly drained Nameoki and Shaffton soils are on slightly higher landform positions nearby.
DRAINAGE AND PERMEABILITY: Poorly drained. The potential for surface water runoff is low or neglible. Permeability is moderately slow. In drained areas, depth to an intermittent apparent high water table is 0.5 foot above the surface to 1.0 foot below from December to April in most years.
USE AND VEGETATION: Most areas are used to grow corn and soybeans. Native vegetation is mixed prairie grasses and hardwoods of cottonwood, maple, pecan, pin oak, and sycamore trees.
DISTRIBUTION AND EXTENT: Flood plains of Mississippi, Illinois, and Ohio Rivers. Extent is small (about 8,800 acres) and is mainly in MLRA 115.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Indianapolis, Indiana
SERIES ESTABLISHED: Jackson County, Illinois, 1932.
REMARKS: Gorham soils were originally described as having 40 to 44 inches of "clayey" material over sandy sediments in Jackson County, Illinois. Later, they were described as having 26 to 40 inches of "clayey" material over sandy sediments.
The typical pedon was sampled and described from the same map unit as the previous typical pedon for this revision.
Diagnostic horizons and features in this pedon include: Mollic epipedon - from the surface of the soil to a depth of 14 inches (Ap and A horizons). Cambic horizon - from a depth of approximately 14 inches to 62 inches (Btg1, Btg2, 2Bt1, 2Bt2, and 2BC horizons). Aquic conditions - endosaturation and reduction indicated by redoximorphic features throughout the soil.
ADDITIONAL DATA: Mechanical data on file - Numbers C72IL-39-1-1 to 11.