LOCATION EDINBURG IL+MOEstablished Series
TAXONOMIC CLASS: Fine, smectitic, mesic Vertic Argiaquolls
TYPICAL PEDON: Edinburg silty clay loam - in a shallow depression in a nearly level cultivated field. (Colors are for moist soil unless otherwise stated.)
Ap--0 to 8 inches; very dark gray (10YR 3/1) silty clay loam, gray (10YR 5/1) dry; moderate fine and medium granular structure; friable; common fine and very fine roots; neutral; abrupt smooth boundary.
A--8 to 10 inches; very dark gray (10YR 3/1) silty clay loam, gray (10YR 5/1) dry; moderate medium granular structure with some moderate very fine subangular blocky; firm; common fine and very fine roots; neutral; clear smooth boundary. (Combined thickness of the A horizon is 10 to 20 inches.)
BE--10 to 16 inches; very dark gray (10YR 3/1) silty clay loam, gray (10YR 5/1) dry; few fine faint very dark grayish brown (2.5Y 3/2), and few fine distinct olive brown (2.5Y 4/4) and dark grayish brown (2.5Y 4/2) mottles; weak and moderate fine subangular blocky structure; firm; common very fine and few fine roots; few distinct light brownish gray (10YR 6/2) dry silt coatings on faces of peds; few fine yellowish brown (10YR 5/8) concretions (iron and manganese oxides); neutral; clear smooth boundary. (0 to 8 inches thick)
Btg1--16 to 20 inches; dark gray (10YR 4/1) silty clay loam; few fine distinct olive brown (2.5Y 4/4) mottles; moderate fine angular blocky structure; firm; many distinct very dark gray (10YR 3/1) clay films on faces of peds; few very fine roots; few fine concretions (iron and manganese oxides); neutral; gradual smooth boundary.
Btg2--20 to 26 inches; dark gray (10YR 4/1) silty clay; few fine distinct olive brown (2.5Y 4/4) mottles; moderate medium prismatic structure parting to moderate medium and coarse angular blocky; firm; common distinct dark gray (10YR 4/1) clay films on faces of peds; few very fine roots; common fine concretions (iron and manganese oxides); slightly acid; gradual smooth boundary.
Btg3--26 to 34 inches; dark gray (10YR 4/1) silty clay loam; common fine distinct yellowish brown (10YR 5/6 and 5/8) mottles; moderate medium prismatic structure parting to moderate coarse angular blocky; firm; common distinct dark gray (10YR 4/1) clay films and few faint very dark gray (10YR 3/1) organic coatings on faces of peds; few very fine roots; few fine concretions (iron and manganese oxides); neutral; gradual smooth boundary.
Btg4--34 to 41 inches; olive gray (5Y 5/2) silty clay loam; many fine and medium prominent yellowish brown (10YR 5/6 and 5/8) mottles; moderate medium prismatic structure parting to moderate coarse angular blocky; firm; few distinct dark gray (10YR 4/1) clay films and very dark gray (10YR 3/1) organic coatings on vertical faces of peds; few very fine roots; few fine concretions (iron and manganese oxides); neutral; gradual smooth boundary. (Combined thickness of the Btg horizon is 16 to 27 inches.)
BCg--41 to 55 inches; olive gray (5Y 5/2) silty clay loam; many fine and medium prominent yellowish brown (10YR 5/6 and 5/8) mottles; weak medium prismatic structure parting to weak coarse angular blocky; friable; few faint dark gray (10YR 4/1) clay films and very dark gray (10YR 3/1) organic coatings on vertical faces of peds; few fine concretions (iron and manganese oxides); neutral; gradual smooth boundary. (8 to 22 inches thick)
C--55 to 60 inches; mottled yellowish brown (10YR 5/6) and light olive gray (5Y 6/2) silt loam; massive; friable; dark gray (10YR 4/1) linings in channels; neutral.
TYPE LOCATION: Sangamon County, Illinois; about 3 miles southwest of Chatham; 1,200 feet south and 276 feet east of the center of sec. 22, T. 14 N., R. 6 W.
RANGE IN CHARACTERISTICS: The depth to the base of the argillic horizon ranges from 40 to 65 inches. The mollic epipedon ranges from 10 to 24 inches in thickness and includes the upper part of the argillic horizon in some pedons. Sand content ranges from 1 to 10 percent in the control section. These soils are not dry for as many as 30 days during the 120 days following the summer solstice.
The Ap or A horizon (upper one-third of the control section) has value of 2 or 3 and chroma of 1 or 2. It is silty clay loam or, less commonly, silt loam. Reaction ranges from medium acid to neutral, although pedons that have been limed range to slightly alkaline. Clean silt grains are evident when the soil is dry.
The BEg or Eg horizon (also part of the upper one-third of the control section) has value of 3 or 4 and chroma of 1 or 2. It is silty clay loam or, less commonly, silt loam. Reaction ranges from moderately acid to neutral. The BE horizon has clean silt grains as coatings on faces of peds. Other pedons have weakly expressed E horizons.
The Btg horizon (the middle one-third of the control section) has hue of 10YR, 2.5Y, or 5Y, value of 3 to 6, and chroma of 1 or 2 with mottles that have chroma of 3 to 8. It commonly is silty clay loam but some pedons are silty clay. Average clay content ranges from 35 and 42 percent clay, but individual subhorizons contain as much as 46 percent clay. Reaction ranges from moderately acid to neutral.
The BCg or Cg horizon (the lower one-third of the control section) has hue of 10YR, 2.5Y, or 5Y, value of 5 or 6, and chroma of 1 or 2 with mottles or mixed colors that have chroma of 3 to 8. Reaction ranges from slightly acid to slightly alkaline.
COMPETING SERIES: These are the
Bremer,
Chancellor,
Clarinda,
Coatsburg,
Crossplain,
Gregory,
Haig,
Lodgepole,
Mazaska,
Minnetonka,
Sampsel,
Taintor,
Virden,
Winterset,
Worthenton, and
Worthing series. Bremer, Chancellor, and Worthing soils have mollic epipedons thicker than 24 inches. Clarinda, Haig, and Minnetonka soils average more than 40 percent clay in the particle size control section. Coatsburg soils average more than 10 percent sand in the control section. Crossplain and Sampsel soils have free carbonates at depths of less than 50 inches. Sampsel soils also have coarse fragments of shale in the lower one-third of the control section. Gregory and Mazaska soils average more than 10 percent sand in the lower one-quarter of the control section. Lodgepole soils are dry in some part of the soil moisture control section for more than 30 days of the 120 days following the summer solstice. Taintor soils average more than 32 percent clay in the first one-quarter of the control section. Virden soils do not have an E horizon or noticeable clean silt grains in the control section. Winterset, Worthenton, and Worthing soils average less than 54 degrees F.
i. the soil temperature control section.
GEOGRAPHIC SETTING: Edinburg soils are in shallow depressions or on flat summits on loess covered Illinoian till plains. Slope gradients commonly are less than 1 percent, but range from 0 to 2 percent. The soils formed in loess. Upon drying, the Edinburg soils normally appear grayer on the landscape than other surrounding Mollisols. The mean annual temperature varies from 50 to 57 degrees F, and the mean annual precipitation varies from about 34 to 40 inches.
GEOGRAPHICALLY ASSOCIATED SOILS: These are Denny, Ipava, Sable and Virden soils. Denny soils are in similar shallow depressions on nearby upland plains and are only adjacent to Edinburg soils in a few places. The somewhat poorly drained Ipava soils are on slightly higher positions. Virden and Sable soils are nearly level but adjacent to and slightly higher than Edinburg soils.
DRAINAGE AND PERMEABILITY: Poorly drained. Runoff is slow. Ponding of brief duration occurs from March to June and after major storms. Permeability is slow.
USE AND VEGETATION: Most areas of Edinburg soils are cultivated. Corn and soybeans are the principal crops. Native vegetation is wet-prairie grasses.
DISTRIBUTION AND EXTENT: Central and southwestern Illinois, and eastern Missouri. The series is of small extent (about 6000 acres correlated).
MLRA OFFICE RESPONSIBLE: Indianapolis, Indiana
SERIES ESTABLISHED: Christian County, Illinois, 1946.
REMARKS: Classification adjusted to agree with ST Issue # 17 on 23 Aug 94 by CLG. The Clarinda, Coatsburg, and Sampsel soils are competed here even though they are still listed as being in the "sloping" family.
Diagnostic horizons and features recognized in this pedon are: mollic epipedon - the zone from the surface to a depth of approximately 16 inches (Ap, A, and BE horizons); argillic horizon - the zone from approximately 16 to 41 inches (Btg1, Btg2, Btg3, and Btg4 horizons); aquoll feature - distinct mottles in the lower part of the mollic epipedon.