LOCATION BIGGSVILLE ILEstablished Series
TAXONOMIC CLASS: Fine-silty, mixed, superactive, mesic Typic Hapludolls
TYPICAL PEDON: Biggsville silt loam on a slope of 1 percent in a cultivated field at an elevation of 630 feet. (Colors are for moist soils unless otherwise stated.)
Ap--0 to 8 inches; very dark gray (10YR 3/1) silt loam; grayish brown (10YR 5/2) dry; moderate very fine and fine granular structure; friable; common fine roots; neutral; abrupt smooth boundary.
AB--8 to 16 inches; very dark grayish brown (10YR 3/2) and brown (10YR 4/3) silt loam; grayish brown (10YR 5/2) dry; moderate medium subangular blocky structure parting to moderate fine granular; friable; few fine roots; neutral; gradual smooth boundary. (Combined thickness of the A horizon is 10 to 20 inches.)
Bw1--16 to 32 inches; brown (10YR 4/3) and dark yellowish brown (10YR 4/4) silt loam; moderate medium prismatic structure parting to moderate medium subangular blocky; friable; few fine roots; few faint very dark grayish brown (10YR 3/2) organic coatings on faces of peds; slightly acid; abrupt smooth boundary.
Bw2--32 to 47 inches; brown (10YR 4/3) silt loam; moderate medium prismatic structure; friable; common medium distinct brown (7.5YR 4/4) and yellowish brown (10YR 5/6) masses of iron accumulation within peds; common medium distinct grayish brown (10YR 5/2) iron depletions within peds; few fine black (7.5YR 2/1) stains (iron-manganese oxides); slightly acid; gradual smooth boundary.
Cg--47 to 80 inches; grayish brown (10YR 5/2), brown (7.5YR 4/4), and yellowish brown (10YR 5/6) silt loam; massive; friable; few fine black (7.5YR 2/1) stains (iron-manganese oxides); slightly acid.
TYPE LOCATION: Rock Island County, Illinois; about 1 mile west of Hillsdale; 1,520 feet west and 200 feet south of northeast corner, sec. 30, T. 19 N., R. 3 E.; USGS Hillsdale quadrangle; latitude 41 degrees 36 minutes 40 seconds N. and longitude 90 degrees 12 minutes 00 seconds W., NAD 27.
RANGE IN CHARACTERISTICS: The depth to the base of the cambic horizon is greater than 42 inches. The cambic horizon contains less than 5 percent sand and less than 27 percent clay. The mollic epipedon is 10 to 20 inches thick.
The upper part of the control section (Ap or A horizons) has value of 2 or 3 (4 or 5 dry), and chroma of 1 to 3. It is moderately acid to moderately alkaline, depending upon past liming practices.
The middle part of the control section (Bw or BC horizons) has hue of 10YR or 7.5YR, value of 3 to 5, and chroma of 3 to 6. The B horizon is usually free of iron depletions to 30 inches or more. It typically averages between 20 and 24 percent clay and ranges from 18 to 27 percent. It is moderately acid to neutral.
The lower part of the control section (C horizon) has hue of 10YR, 7.5YR, or 2.5Y, value of 4 to 6, and chroma of 2 to 6. It is slightly acid to moderately alkaline.
COMPETING SERIES: These are the Annieville, Dinsmore, Exira, Galva, Keg, Marshall, Monona, Northboro, Ponca, Port Byron, Raddle, Salix, and Truman series. Annieville soils formed in 40 to 60 inches of loess over glacial till. Dinsmore soils formed in 40 to 60 inches of loess and the underlying glacial till. Exira soils contain gray relict redoximorphic features above 40 inches. Galva soils average 27 to 35 percent clay in the particle-size control section. Keg soils formed in silty alluvium on flood plains and have carbonates above 30 inches. Marshall soils average 27 to 34 percent clay in the particle-size control section. Monona soils do not have zones within 60 inches that are frequently saturated for periods longer than one month. Northboro soils average more than 10 percent sand in the lower part of the control section. Ponca soils have carbonates from 14 to 24 inches. Port Byron soils do not have redoximorphic features in the middle part of the control section. Raddle soils have an irregular decrease in clay and average more than 10 percent sand in the middle and lower parts of the control section. Salix soils formed in silty alluvium on flood plains and have carbonates within 30 inches. Truman soils have calcium carbonate equivalent range of 5 to 15 percent in the lower part of the series control section.
GEOGRAPHIC SETTING: Biggsville soils are on ridgetops, side slopes and swales on uplands. Slope gradients are 0 to 10 percent. Biggsville soils formed in thick coarse textured loess. Mean annual air temperature ranges from 47 to 54 degrees F. Mean annual precipitation ranges from 36 to 40 inches.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the Joy, Mt. Carroll, Port Byron and Seaton soils. All these soils are on similar landforms. Joy soils have redoximorphic features throughout the lower part of the series control section. Mt. Carroll soils have an argillic horizon. Port Byron soils do not have redoximorphic features in the middle part of the series control section. Seaton soils do not have a mollic epipedon and have an argillic horizon.
DRAINAGE AND PERMEABILITY: The soil moisture wet is within a depth of 4 to 6 feet from December through June in most years. Permeability is moderate. Runoff is low or medium.
USE AND VEGETATION: Soils are cultivated. Corn, soybeans, and small grains are the principal crops. Native vegetation is prairie grasses.
DISTRIBUTION AND EXTENT: LRR M, MLRAs 108B, 115C; West-central and northwestern Illinois and possibly surrounding states. The series is of minor extent.
MLRA OFFICE RESPONSIBLE: Indianapolis, Indiana
SERIES ESTABLISHED: Bureau County, Illinois, 1996.
REMARKS: Diagnostic horizons and features recognized in this pedon are: particle-size control section - the zone from 10 to 40 inches; series control section - the zone from 0 to 60 inches; mollic epipedon - the zone from the surface to 16 inches (Apand AB horizons); cambic horizon - the zone from 16 to 47 inches (Bw horizons). Udic moisture regime. Cation exchange activity class is inferred from lab data from similar soils in the surrounding area. Taxonomic Version: Second Edition, 1999.
These soils were previously correlated as the Port Byron series, moderately wet phase.