LOCATION EMMA ILEstablished Series
TAXONOMIC CLASS: Fine-silty, mixed, active, mesic Oxyaquic Dystrudepts
TYPICAL PEDON: Emma silty clay loam (wooded area). (Colors and consistence for moist conditions unless otherwise noted.)
A1--0 to 4 inches; very dark grayish brown (10YR 3/2) silty clay loam; moderate, medium, granular structure; friable; slightly acid; abrupt smooth boundary. (3 to 5 inches thick)
A2--4 to 8 inches; mixed dark grayish brown (10YR 4/2) and brown (10YR 4/3 and 5/3) silty clay loam; weak, medium, granular structure; friable; strongly acid; clear smooth boundary. (4 to 6 inches thick)
B1--8 to 14 inches; mixed brown (10YR 4/3) and dark yellowish brown (10YR 4/4) silty clay loam; few medium faint yellowish brown (10YR 5/6) mottles; weak, medium subangular blocky structure; friable; strongly acid; clear smooth boundary. (5 to 8 inches thick)
B21--14 to 23 inches; yellowish brown (10YR 5/4) silty clay loam, common, medium faint, dark yellowish brown (10YR 4/4) mottles; moderate medium and coarse subangular blocky structure; firm; many thin dark yellowish brown (10YR 4/4) clay coatings and continuous thick brown (10YR 5/3) silt coatings in the upper part; very strongly acid; clear smooth boundary. (8 to 11 inches)
B22--23 to 28 inches; yellowish brown (10YR 5/4) silty clay loam with few fine faint dark brown (7.5YR 4/4) mottles and some pale brown (10YR 6/3) silt coatings; weak and moderate medium subangular blocky structure; firm; very strongly acid; clear smooth boundary. (5 to 8 inches thick)
B23--28 to 44 inches; yellowish brown (10YR 5/4) silty clay loam, few fine faint dark brown (7.5YR 4/4) mottles and some light brownish gray (10YR 6/2) silt coatings; weak coarse prismatic structure parting to weak medium subangular blocky; firm; very strongly acid; clear smooth boundary. (12 to 16 inches thick)
B3--44 to 58 inches; yellowish brown (10YR 5/4) silty clay loam, many medium distinct light brownish gray (10YR 6/2) mottles; weak coarse prismatic structure; firm; continuous light brownish gray (10YR 6/2) silt coatings in the upper part becoming patchy in lower part; very strongly acid; diffuse smooth boundary. (6 to 14 inches thick)
C1--58 to 72 inches; light brownish gray (10YR 6/2) silty clay loam, many distinct yellowish brown (10YR 5/4) mottles; massive; firm; very strongly acid.
TYPE LOCATION: Gallatin County, Illinois; about 8 miles northeast of Shawneetown, 2,040 feet south and 850 feet east of the northwest corner of sec. 27, T. 8 S., R. 10 E.
RANGE IN CHARACTERISTICS: Solum thickness commonly is about 4 1/2 to 5 feet but ranges from about 4 to about 5 1/2 feet. The mean annual soil temperature ranges between 54 and 59 degrees F. Reaction throughout the solum (except A1 or Ap) ranges from strongly to extremely acid. Base saturation is less than 60 percent by ammonium acetate.
The A horizon typically is medium silty clay loam but ranges up to 40 percent clay. The A1 or Ap horizon is 10YR 3/2 or 4/2. In wooded areas the A1 commonly is 3 to 4 inches thick; in cultivated areas the Ap commonly is 6 to 9 inches thick with the A2 incorporated.
The B horizon commonly is yellowish brown but ranges to brown and dark yellowish brown. Brown to dark brown mottles commonly occur in the B22 horizon and with increasing depth they become more numerous and grayer in color. The B horizon has texture of medium silty clay loam. Some subhorizons commonly are heavy silty clay loam. Average clay content of the B horizon is less than 35 percent. A few clay films are present in some pedons but the B/A clay ratio is less than 1.2. Structure in the B horizon has grade of weak or moderate. Thickness of the B horizon commonly ranges from 45 to 55 inches but in some pedons ranges to as thin as 36 inches.
The C horizon is heavy silt loam or light silty clay loam.
COMPETING SERIES: These are the Belle, Calawah, and Coosbay soils. These soils occur in areas of higher rainfall. They have a high winter rainfall and dry summer periods.
GEOGRAPHIC SETTING: Emma soils typically are nearly level or gently sloping. They are on terrace or second bottom positions along the Ohio River flood plains. Slopes commonly are less than 2 percent but range to 12 percent. The soils formed in acid water-laid sediments of mixed mineralogical composition. Climate consists of hot summers and cold winters with mean annual temperatures between 45 and 57 degrees F and precipitation between 35 and 45 inches per year.
GEOGRAPHICALLY ASSOCIATED SOILS: Emma soils are on similar landscape as the associated Sciotoville, Armiesburg, and Hurst soils and are on slightly higher positions than the associated Petrolia and Cape soils. Sciotoville soils have a fragipan horizon. Armiesburg soils have a mollic epipedon and higher reaction in the sola. Hurst soils have an argillic horizon. Petrolia and Cape soils are alluvial soils that formed in slack water sediments. In addition Cape soils contain more clay in the 10- to 40-inch control section.
DRAINAGE AND PERMEABILITY: Naturally moderately well drained. Surface runoff is slow to medium. Permeability is moderately slow. Emma soils flood rarely for brief duration from March through June. The water table is within 2.5 to 4 feet of the surface from February through April. USE AND VEGETATION: Used for cultivated crops such as corn, soybeans, and meadow, and for hardwood forrest such as oak and ash.
DISTRIBUTION AND EXTENT: Along Ohio River flood plain in southern Illinois and possibly northern Kentucky and southern Indiana. Extent is small.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Indianapolis, Indiana
SERIES ESTABLISHED: Gallatin County, Illinois, 1971.
REMARKS: Classification adjusted to agree with STK Issue #17 on 23 Aug 94 by CLG. These soils are about on the line between thermic and mesic areas as calculated from air temperatures, but are considered to be more typically mesic.