LOCATION BLACKOAR MO+ILEstablished Series
TAXONOMIC CLASS: Fine-silty, mixed, superactive, mesic Fluvaquentic Endoaquolls
TYPICAL PEDON: Blackoar silt loam - in a cultivated field. (Colors are for moist soil unless otherwise stated.)
Ap--0 to 6 inches; very dark gray (10YR 3/1) silt loam, dark gray (10YR 4/1) dry; weak very fine granular structure; very friable; many roots; neutral; clear smooth boundary.
A--6 to 18 inches; very dark gray (10YR 3/1) silt loam, dark gray (10YR 4/1) dry; weak fine granular structure; very friable; common roots; many fine pores; slightly acid; clear smooth boundary. (Combined thickness of the A horizon is 10 to 24 inches.)
Bg--18 to 40 inches; stratified gray (10YR 5/1) and dark gray (10YR 4/1) silt loam; weak fine subangular blocky structure; friable; few roots; many fine pores; common fine distinct dark brown (10YR 3/3) masses of iron accumulation throughout; few fine dark concretions (oxides); slightly acid; gradual smooth boundary. (20 to 40 inches thick)
Cg--40 to 60 inches; stratified gray (10YR 5/1) and dark gray (10YR 4/1) silt loam; massive; friable; few roots; few fine pores; common medium distinct dark yellowish brown (10YR 4/4) masses of iron accummulation throughout; few fine dark concretions (oxides); slightly acid.
TYPE LOCATION: Caldwell County, Missouri; 6 miles northeast of Braymer; 2,400 feet north of center, sec. 13, T. 56 N., R. 26 W.
RANGE IN CHARACTERISTICS: The thickness of the solum ranges from 36 to 60 inches or more. Reaction commonly is slightly acid, but includes moderately acid and neutral. The particle-size control section averages between 18 and 27 percent clay. Mineralogy of the clay fraction is dominantly montmorillonite. The thickness of the mollic epipedon ranges from 10-24 inches.
The A horizon has hue of 10YR; value of 2 or 3 moist, 4 or 5 dry; and chroma of 1 or 2.
The Bg and Cg horizons have hue of 10YR to 5Y in the matrix, value of 4 to 6, and chroma of 2 or less with higher chroma mottles. The Cg horizon is silt loam or silty clay loam.
COMPETING SERIES: This is the Beaucoup series. Beaucoup soils average 27 to 35 percent clay in the particle-size control section.
GEOGRAPHIC SETTING: Blackoar soils are on nearly level flood plains. Slopes range from 0 to 2 percent. The soils formed in silty alluvium. The mean annual temperature ranges from 49 to 56 degrees F, and mean annual precipitation ranges from 32 to 40 inches.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the Colo, Kennebec, Wabash and Zook soils. Colo and Kennebec soils have mollic epipedons more than 36 inches thick. Kennebec soils are on slightly higher flood plains adjacent to the streams. Colo soils are on similar positions. Wabash and Zook soils average more than 35 percent clay in the particle size control section, and are commonly on lower flood plains or depressional areas.
DRAINAGE AND PERMEABILITY: Poorly drained. Runoff is slow or very slow. Permeability is moderate. An apparent water table has an upper limit of 0 to 1.0 feet from November to May. Flooding is rare to common.
USE AND VEGETATION: Most areas are cropped to corn and soybeans. Native vegetation is water tolerant grasses and sedges with some hardwoods.
DISTRIBUTION AND EXTENT: West-central and northern Missouri and Illinois. The series is of large extent.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Indianapolis, Indiana
SERIES ESTABLISHED: Scotland County, Missouri, 1969.
REMARKS: Diagnostic horizons and features recognized in this series are: mollic epipedon - zone from the surface of the soil to a depth of 18 inches (Ap and A horizons); cambic horizon - zone from approximately 28 to 40 inches (Bg horizon).