LOCATION RICHWOOD IL+IA MN WIEstablished Series
TAXONOMIC CLASS: Fine-silty, mixed, superactive, mesic Typic Argiudolls
TYPICAL PEDON: Richwood silt loam, on a 3 percent slope, in a cultivated field, at an elevation of about 232 meters (760 feet) above sea level. (Colors are for moist soil unless otherwise stated.)
Ap--0 to 15 centimeters (0 to 6 inches): very dark grayish brown (10YR 3/2) silt loam, dark grayish brown (10YR 4/2) dry; weak very fine subangular blocky structure parting to weak medium granular; friable; many fine fibrous roots; slightly acid; abrupt smooth boundary.
A--15 to 33 centimeters (6 to 13 inches); very dark grayish brown (10YR 3/2) silt loam, dark grayish brown (10YR4/2) dry; moderate fine and medium subangular blocky structure; friable; common fibrous roots; slightly acid; clear smooth boundary. [Combined thickness of the A horizons is 25 to 51 centimeters (10 to 20 inches).]
AB--33 to 46 centimeters (13 to 18 inches); dark brown (10YR 3/3) and dark yellowish brown (10YR 4/4) silt loam; moderate fine and medium subangular blocky structure; friable; common fibrous roots; common distinct very dark grayish brown (10YR 3/2) organic coats on ped faces; slightly acid; clear smooth boundary. [0 to 13 centimeters (0 to 5 inches) thick]
Bt1--46 to 74 centimeters (18 to 29 inches); dark yellowish brown (10YR 4/4) silt loam; moderate fine and medium subangular blocky structure; friable; common distinct brown (10YR 4/3) clay films on faces of peds; moderately acid; clear smooth boundary.
Bt2--74 to 117 centimeters (29 to 46 inches); yellowish brown (10YR 5/4) silt loam; moderate medium and coarse subangular blocky structure; friable; common distinct dark yellowish brown (10YR 4/4) clay films on faces of peds; moderately acid; clear smooth boundary. [Combined thickness of the Bt horizons is 30 to 76 centimeters (12 to 30 inches).]
2BC--117 to 152 centimeters (46 to 60 inches); strong brown (7.5YR 5/6) stratified fine sandy loam and loamy sand; weak coarse subangular blocky structure; friable; few distinct brown (10YR 4/3) clay films on faces of peds; moderately acid.
TYPE LOCATION: Whiteside County, Illinois; about 2.5 miles northwest of Morrison; about 520 feet east and 2000 feet south of the northwest corner of section 2, T. 21 N., R. 4 E.
RANGE IN CHARACTERISTICS: The mollic epipedon ranges from 25 to 51 centimeters (10 to 20 inches) thick. The loess or silty material ranges from 102 to 152 centimeters (40 to 60 inches) thick. Depth to carbonates is greater than 152 centimeters (60 inches). The particle-size control section averages 20 and 27 percent clay. The particle-size control section averages less than 15 percent sand. These soils do not have rock fragments.
The Ap or A horizon has hue of 10YR, value of 2 or 3, and chroma of 1 to 3. It is silt loam. Clay content ranges from 15 to 22 percent. Reaction ranges from moderately acid to neutral.
The AB horizon has hue of 10YR, value of 3 or 4, and chroma of 3 or 4. It is silt loam or silty clay loam. Clay content ranges from 18 to 30 percent. Reaction ranges from moderately acid to neutral. Some pedons have a BA horizon.
The Bt horizon has hue of 7.5YR or 10YR, value and chroma of 3 to 5. It is silt loam or silty clay loam. Clay content ranges from 20 to 30 percent. Sand content is less than 15 percent. Reaction ranges from moderately acid to neutral. Clay films are few to many and faint to distinct on faces of peds.
The 2BC or 2Bt horizon has 10YR or 7.5YR hue, value of 3 to 5, and chroma of 3 to 6. It is stratified silt loam, loam, fine sandy loam, sandy loam, loamy fine sand, or loamy sand. Clay content ranges from 10 to 20 percent. Average sand content ranges from 50 to 90 percent. Reaction ranges from moderately acid to neutral.
The 2C horizon, where present, has 10YR or 7.5YR hue, value of 4 to 8, and chroma of 2 to 6. It is fine sand or sand. Clay content ranges from 1 to 4 percent. Sand content ranges from 90 to 98 percent. Reaction is slightly acid or neutral.
COMPETING SERIES: These are the Ashdale, Broadwell, Dinsdale, Douglas, Elkhart, Elmont, Healing, Lycurgus, Malcolm, Meadowbank, Mickle(T), Ogle, Osco, Parkway, Plano, Proctor, Ripon, Sibley, Sidell, Tama, Tecumseh, Toddville, Wakenda, Waupecan, and Wiota series. Ashdale soils have limestone bedrock within a depth of 102 to 152 centimeters (40 to 60 inches). Broadwell soils average more than 27 percent clay in the particle-size control section. Dinsdale soils have 20 to 30 percent clay in the lower third of the series control section. Douglas soils average between 27 and 35 percent clay in the particle-size control section. Elkhart soils have carbonates within a depth of 102 centimeters (40 inches) and have less than 8 percent sand in the lower third of the series control section. Elmont soils have a paralithic contact with shale within a depth of 152 centimeters (60 inches). Healing soils average less than 50 percent sand in the lower third of the series control section. Lycurgus soils have less than 10 percent sand in the lower third of the series control section. Malcolm soils have less than 50 percent sand in the lower third of the series control section. Meadowbank soils have 20 to 50 percent sand in the middle third of the series control section. Mickle(T) soils have less than 50 percent sand in the lower third of the series control section. Ogle soils have 5YR hue on ped surfaces or in the matrix of at least one subhorizon within the series control section. Osco soils have less than 7 percent sand in all parts of the series control section. Parkway soils average 20 to 35 percent clay in the lower third of the series control section. Plano soils average 27 to 35 percent clay in the particle-size control section. Proctor soils have more than 15 percent sand within a depth of 102 centimeters (40 inches). Ripon soils have limestone bedrock within a depth of 102 centimeters (40 inches). Sibley soils have a mollic epipedon 61 to 91 centimeters (24 to 36 inches) thick. Sidell soils have 2 to 10 percent gravel in the lower third of the series control section. Tama soils have less than 10 percent sand in the series control section. Tecumseh soils have 2 to 10 percent rock fragments in the lower third of the series control section. Toddville soils have a saturated zone within a depth of 183 centimeters (72 inches) for 1 month or more per year in normal years. Wakenda soils have less than 10 percent sand in the series control section. Waupecan soils average more than 15 percent gravel in the lower third of the series control section. Wiota soils have less than 15 percent sand in the series control section.
GEOGRAPHIC SETTING: These soils are on outwash plains and stream terraces. Slopes range from 0 to 12 percent. They formed in loess or other silty deposits 102 to 152 centimeters (40 to 60 inches) thick and in the underlying water-laid stratified fine and medium sand. Mean annual precipitation ranges from 66 to 89 centimeters (26 to 35 inches). Mean annual air temperature ranges from 7 to 14 degrees C (45 to 57 degrees F). Elevation ranges from 213 to 595 meters (700 to 1,950 feet) above sea level. Frost-free period ranges from 110 to 180 days.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the Bertrand, Parkway, and Port Byron soils. The well drained Bertrand soils have thinner or lighter colored surface layers, and are on similar positions nearby. The well drained Parkway soils are on similar positions on till plains nearby. The Port Byron soils occupy similar positions and have less than 15 percent sand in the series control section.
DRAINAGE AND PERMEABILITY: Well drained. These soils do not have a seasonally saturated zone within a depth of 183 centimeters (72 inches) in normal years. Surface runoff potential is low or medium. Permeability is moderate in the loess or silty deposits and rapid in the underlying stratified sediments.
USE AND VEGETATION: Most areas are cultivated. The principal crops are corn, soybeans, small grain, and forage. The native vegetation is big bluestem, little bluestem, prairie dropseed, and other prairie grasses with occasional scattered oak or hickory trees in its northern extent.
DISTRIBUTION AND EXTENT: LRR M, MLRAs 90, 104, 105, 108, 109, 115C; Illinois, southwestern Wisconsin, southeastern Minnesota, and eastern Iowa. This series is moderately extensive.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: St. Paul, Minnesota
SERIES ESTABLISHED: La Crosse County, Wisconsin, 1957.
REMARKS: Particle-size control section - the zone from a depth of 46 to 96 centimeters (18 to 38 inches) (Bt1 and part of Bt2 horizons);
Series control section - the zone from the surface of the soil to a depth of 152 centimeters (60 inches) (Ap, A, AB, Bt1, Bt2, and 2BC horizons).
Diagnostic horizons and features recognized in this pedon:
mollic epipedon - the zone from the surface of the soil to a depth of 46 centimeters (18 inches) (Ap, A, AB horizons);
argillic horizon - zone from 46 to 117 centimeters (18 to 46 inches (Bt1, Bt2 horizons);
udic moisture regime.
Cation-exchange activity class is inferred from lab data for similar soils.
Taxonomy version--second edition, 1999.
The type location was relocated from La Crosse County, Wisconsin to Whiteside County, Illinois in February 2003. These soils were not correlated in the update of the soils in La Crosse County, Wisconsin.