LOCATION TWOMILE MO+ILEstablished Series
TAXONOMIC CLASS: Fine-silty, mixed, active, mesic Typic Albaqualfs
TYPICAL PEDON: Twomile silt loam - on a nearly level slope in a cultivated field. (Colors are for moist soil unless otherwise stated.)
Ap--0 to 9 inches; dark grayish brown (10YR 4/2) silt loam, light brownish gray (10YR 6/2) dry; moderate very fine granular structure; very friable; few fine roots; moderately acid; abrupt smooth boundary. (4 to 10 inches thick)
E1--9 to 16 inches; grayish brown (10YR 5/2) silt loam; common medium distinct dark yellowish brown (10YR 3/4) mottles; weak medium platy structure parting to weak fine subangular blocky; very friable; few fine roots; common fine black concretions (Fe & Mn oxides); very strongly acid; abrupt smooth boundary.
E2--16 to 24 inches; light brownish gray (10YR 6/2) silt loam; common fine prominent dark yellowish brown (10YR 3/4) mottles; weak medium platy structure; friable; few fine roots; common fine and medium black concretions (Fe & Mn oxides); strongly acid; clear smooth boundary. (Combined thickness of the E horizon is 8 to 16 inches.)
Egx--24 to 33 inches; gray (10YR 6/1) silt loam, white (10YR 8/1) dry; common medium prominent dark brown (10YR 4/3) and strong brown (7.5YR 5/6) mottles; weak thick platy structure; firm; compact with a variable weakly and moderately expressed brittleness when moist; many fine and medium black concretions (Fe & Mn oxides); very strongly acid; abrupt smooth boundary. (4 to 12 inches thick)
Btg--33 to 52 inches; grayish brown (2.5Y 5/2) silty clay loam; common fine prominent strong brown (7.5YR 5/8) and common fine distinct dark brown (10YR 3/3) mottles; moderate very fine subangular blocky structure; firm; common faint clay films on faces of peds; very strongly acid; clear smooth boundary. (15 to 40 inches thick)
BCg--52 to 62 inches; gray (10YR 6/1) and grayish brown (10YR 5/2) silty clay loam; common medium distinct dark yellowish brown (10YR 4/4) and few fine prominent yellowish red (5YR 4/6) mottles; weak medium platy structure parting to weak fine subangular blocky; firm; common fine black concretions (Fe & Mn oxides); very strongly acid; gradual wavy boundary. (0 to 12 inches thick)
2Cg--62 to 72 inches; gray (10YR 6/1) and grayish brown (10YR 5/2) clay loam; massive; firm; common fine black concretions (Fe & Mn oxides); common fine dark brown (10YR 3/3) stains; contains about 5 percent rounded chert pebbles; strongly acid.
TYPE LOCATION: Montgomery County, Missouri; about 1 mile north of Middletown; 40 feet south and 10 feet west of the northeast corner of sec. 1, T. 50 n., R. 5 W.
RANGE IN CHARACTERISTICS: Thickness of the A and E horizons is 24 to 36 inches. Depth to the 2B or 2C horizon is greater than 40 inches.
The Ap horizon has color value of 4 or 5 and chroma of 1 to 3. It is very strongly acid to neutral.
The E horizon has hue of 10YR or 2.5Y, value of 4 to 6 and chroma of 1 or 2 and mottles of higher or lower chroma and value. It is silt loam or silt containing 10 to 18 percent clay and ranges from extremely acid to moderately acid. The Egx horizon has weak to moderately expressed fragipan-like brittleness when moist.
The Btg horizon has hue of 10YR or 2.5Y, value of 4 to 6, and chroma of 1 or 2 with mottles of higher or lower value and chroma. It is silt loam or silty clay loam with 25 to 35 percent clay. Reaction is extremely acid to moderately acid. The BCg or 2BCg horizon is similar to the Btg horizon in color and texture and very strongly acid to slightly acid.
The Cg or 2Cg horizon has hue of 10YR or 2.5Y, value of 5 or 6 and chroma of 1 or 2. It is silt loam, loam, silty clay loam, or clay loam. Reaction is very strongly acid to neutral.
COMPETING SERIES: There are no other series in the same family. Similar series in other families are the Auxvasse, Moniteau, and Racoon series. Auxvasse soils have more than 35 percent clay in the argillic horizon. Moniteau and Racoon soils do not have compact, brittle lower E horizons and the abrupt textural increase.
GEOGRAPHIC SETTING: Twomile soils are on high flood plains and have slope gradients of 0 to 2 percent. They formed in loess or loess and alluvium. Mean annual temperature ranges from 51 to 57 degrees F, and mean annual precipitation ranges from 33 to 43 inches.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the Armster, Chariton, Mexico, Nodaway, and Sharon soils. Armster and Mexico soils have thin dark-colored surface horizons and fine argillic horizons and are on adjoining uplands. Chariton soils have more than 35 percent clay in the argillic horizon and are on higher flood plains or low terraces next to the uplands. Nodaway and Sharon soils do not have argillic horizons and are on adjoining lower flood plains.
DRAINAGE AND PERMEABILITY: Poorly drained. Runoff is slow. Permeability is slow. A perched water table has an upper limit of 1.0 to 2.0 feet during November to May. Flooding is rare or occasional.
USE AND VEGETATION: Twomile soils are used to grow corn, wheat, and soybeans. Some areas are used for hay or pasture and some are forested. Native vegetation is hardwood forest.
DISTRIBUTION AND EXTENT: Missouri and west-central Illinois. These have large extent.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Indianapolis, Indiana
SERIES ESTABLISHED: Montgomery-Warren Counties, Missouri, 1975.
REMARKS: The high silt content and density of the E horizon make this soil more dry than texture would indicate. Diagnostic horizons and features recognized in this series are: ochric epipedon - the zone from the surface of the soil to a depth of 33 inches (Ap, E1, E2 and Egx horizons); albic horizon - the zone from approximately 9 to 33 inches (E1, E2 and Egx horizons); argillic horizon - the zone from approximately 33 to 52 inches (Btg horizon); an abrupt textural change is present between the Egx and Btg horizons.