LOCATION MARISSA ILEstablished Series
TAXONOMIC CLASS: Fine-silty, mixed, superactive, mesic Argiaquic Argialbolls
TYPICAL PEDON: Marissa silt loam. (Colors are for moist soil unless otherwise stated.)
A--0 to 12 inches; very dark gray (10YR 3/1) silt loam, gray (10YR 5/1) dry; weak fine granular structure; friable; neutral; clear smooth boundary. (10 to 14 inches thick)
Eg--12 to 18 inches; dark gray (10YR 4/1) silt loam; weak medium platy structure parting to weak fine granular; friable; slightly acid; clear smooth boundary. (4 to 8 inches thick)
BEg--18 to 22 inches; grayish brown (10YR 5/2) silty clay loam; weak medium subangular blocky structure parting to weak medium granular; firm; many distinct yellowish brown (10YR 5/4) accumulations of iron and manganese accumulations in the matrix; neutral; clear smooth boundary. (3 to 6 inches thick)
Btg1--22 to 35 inches; grayish brown (2.5Y 5/2) silty clay loam; weak coarse prismatic structure parting to strong fine and medium subangular blocky; firm; continuous dark gray (10YR 4/1) clay films; common fine faint light olive brown (2.5Y 5/4) masses of iron and manganese accumulations; few black (10YR 2/1) iron and manganese oxide concretions; neutral; clear smooth boundary.
Btg2--35 to 43 inches; dark grayish brown (2.5Y 4/2) silty clay loam; weak medium subangular blocky structure; firm; thin discontinuous dark gray (10YR 4/1) clay films; many fine and medium faint light olive brown (2.5Y 5/4) masses of iron and manganese accumulations; many dark iron and manganese oxide concretions; neutral; clear smooth boundary. (Combined thickness of the Btg horizon is 20 to 35 inches.)
C1--43 to 50 inches; light olive brown (2.5Y 5/4) and light yellowish brown (2.5Y 6/4) silt loam; massive; friable; slightly alkaline. (5 inches to several feet thick)
C2--50 to 60 inches; light yellowish brown (2.5Y 6/4) silt loam; massive; friable; many yellowish brown (10YR 5/8) masses of iron and manganese accumulations in the matrix; strong effervescence; moderately alkaline.
TYPE LOCATION: Gallatin County, Illinois; about 3 miles northwest of Ridgway, 1,740 feet north and 150 feet west of the southeast corner of sec. 11, T. 8 S., R. 8 E.
RANGE IN CHARACTERISTICS: Solum thickness normally is 40 to 55 inches, but ranges to 65 inches. The depth to the top of the argillic horizon ranges from 14 to 24 inches. Reaction ranges from slightly acid to neutral in the solum. Depth to carbonates typically ranges from 40 to 60 inches. Mean annual soil temperature ranges from 54 to 59 degrees F.
The Ap or A horizon has hue 10YR, value of 2 or 3, and chroma of 1 or 2. It is silt loam.
The Eg horizon has hue of 10YR, value of 4 or 5, and chroma of 1 or 2. It is silt loam. .
The Btg horizon has hue of 10YR or 2.5Y, value of 4 to 6, and chroma of 2 or 3. Redox features range from few to many and from faint to prominent. Average clay content is about 32 to 34 percent, but thin subhorizons contain as much as 40 percent clay.
The C or Cg horizon typically is silt loam, but it includes stratified sandy loam and silty clay loam.
COMPETING SERIES: These are the Corley, Ebbert, Edgington, Knight, Normal, Speed, Thorp, and Vesser series. Corley, Ebbert, Normal, and Vesser soils do not have carbonates within the series control section. Edgington, Knight, and Speed soils are more than 24 inches to the top of the argillic horizon. Thorp soils average more than 15 percent sand in the lower part of the argillic horizon.
GEOGRAPHIC SETTING: Marissa soils are on nearly level stream terraces. They formed in loess or loess-like materials of Wisconsin Age. Summers are hot and winters are cold. Mean annual air temperature ranges from about 54 to 57 degrees F., and mean annual precipitation ranges from about 41 to 45 inches.
GEOGRAPHICALLY ASSOCIATED SOILS: The most common close geographic associates are the wetter Patton soils which do not have albic horizons and the less wet Reesville soils which do not have mollic epipedons. Associated soils on nearby landscapes are in the Camden, Starks, and Uniontown series all of which are less wet and lack mollic epipedons.
DRAINAGE AND PERMEABILITY: Somewhat poorly or poorly drained. Potential for surface runoff is low. Permeability is moderate or moderately slow. In normal years the depth to the top of the apparent seasonal high water table ranges from at the surface to a depth of 1.5 feet in spring.
USE AND VEGETATION: Largely under cultivation; corn, soybeans, small grain, and hay are major crops. Native vegetation is prairie grass.
DISTRIBUTION AND EXTENT: MLRA 113 and 115A in southern Illinois. The soil is of small extent.
MLRA OFFICE RESPONSIBLE: Indianapolis, Indiana
SERIES ESTABLISHED: Wabash County, Illinois, 1931.
REMARKS: Diagnostic horizons and features recognized in this pedon are:
Mollic epipedon -- the zone from the surface to a depth of 12 inches (A horizon);
Albic horizon -- the zone from 12 to 18 inches (Eg horizon);
Argillic horizon -- the zone from 22 to 43 inches (Btg1 and Btg2 horizons)