LOCATION CALCO IA+IL KS MN NE SDEstablished Series
TAXONOMIC CLASS: Fine-silty, mixed, superactive, calcareous, mesic Cumulic Endoaquolls
TYPICAL PEDON: Calco silty clay loam, on a 1 percent slope, on a floodplain, in a cultivated field, at an elevation of about 332 meters above sea level. (Colors are for moist soil unless otherwise stated.)
Ap--0 to 20 centimeters; black (10YR 2/1) silty clay loam, dark gray (10YR 4/1) dry; weak fine and medium subangular blocky structure; friable; common fine roots; common fine tubular pores; about 2 percent very fine snail fragments; strongly effervescent; slightly alkaline; abrupt smooth boundary.
A1--20 to 41 centimeters; black (N 2.5/0) silty clay loam, dark gray (10YR 4/1) dry; weak fine subangular blocky structure; friable; few very fine roots; common fine tubular pores; about 2 percent very fine snail fragments; strongly effervescent; slightly alkaline; gradual smooth boundary.
A2--41 to 71 centimeters; black (N 2.5/0) silty clay loam, dark gray (10YR 4/1) dry; weak very fine and fine subangular blocky structure; friable; few very fine roots; common very fine tubular pores; about 5 percent very fine snail fragments; strongly effervescent; slightly alkaline; gradual smooth boundary.
A3--71 to 97 centimeters; black (N 2.5/0) silty clay loam, dark gray (10YR 4/1) dry; weak very fine prismatic structure parting to weak fine subangular blocky; friable; common very fine tubular pores; about 4 percent very fine snail fragments; common fine distinct very dark grayish brown (2.5Y 3/2) redoximorphic depletions; strongly effervescent; slightly alkaline; clear smooth boundary. (Combined thickness of the A horizon is 75 to more than 150 centimeters.)
Bg1--97 to 117 centimeters; very dark gray (2.5Y 3/1) silty clay loam, dark grayish brown (10YR 4/2) dry; weak very fine prismatic structure parting to weak fine subangular blocky; friable; common very fine tubular pores; about 3 percent very fine snail fragments; common fine faint dark grayish brown (2.5Y 4/2) redoximorphic depletions; strongly effervescent; slightly alkaline; clear smooth boundary.
Bg2--117 to 147 centimeters; about 95 percent very dark gray (5Y 3/1) and about 5 percent dark gray (5Y 4/1) silt loam, gray (5Y 5/1) dry; weak fine prismatic structure parting to weak medium subangular blocky; friable; common very fine tubular pores; common fine prominent light olive brown (2.5Y 5/4) redoximorphic concentrations; very slightly effervescent; moderately alkaline; gradual smooth boundary. (Combined thickness of the Bg horizon is 25 to 60 centimeters.)
BCg--147 to 175 centimeters; about 95 percent very dark gray (5Y 3/1) and about 5 percent dark gray (5Y 4/1) silt loam, gray (5Y 5/1) dry; weak medium prismatic structure; friable; common very fine tubular pores; common fine prominent light olive brown (2.5Y 5/4) redoximorphic concentrations; very slightly effervescent; slightly alkaline; abrupt smooth boundary. (0 to 60 centimeters thick)
Cg--175 to 203 centimeters; very dark gray (5Y 3/1) silt loam; massive; friable; common very fine tubular pores; common fine prominent dark yellowish brown (10YR 3/4) redoximorphic concentrations; very slightly effervescent; slightly alkaline.
TYPE LOCATION: Major Land Resource Area (MLRA) 107B-Iowa and Minnesota Deep Loess Hills, Cass County, Iowa subset; about 1/4 mile south of Griswold; located about 2,240 feet south and 160 feet east of northwest corner of section 8, T. 74 N., R. 37 W.; USGS Griswold topographic quadrangle; lat. 41 degrees 13 minutes 23.3 seconds N. and long. 95 degrees 8 minutes 9.5 seconds W., NAD 83.
RANGE IN CHARACTERISTICS:
Thickness of the mollic epipedon--75 to more than 150 centimeters
Depth to carbonates--0 to 25 centimeters
Depth to gypsum and other salts--more than 200 centimeters
Clay content in the particle-size control section (weighted average)--24 to 35 percent
Sand content in the particle-size control section (weighted average)--1 to 15 percent
Ap or A horizon:
Hue--10YR, 5Y, or neutral
Value--2, 2.5, or 3
Chroma--0 or 1
Texture--silt loam or silty clay loam
Clay content--24 to 35 percent
Sand content--1 to 15 percent
Reaction--slightly alkaline or moderately alkaline
Some pedons have subhorizons below a depth of 50 centimeters that are not effervescent and have a reaction range of neutral or slightly alkaline
Some pedons have an AC horizon
Bg or BCg (when present) horizons:
Hue--10YR, 2.5Y, 5Y or neutral
Value--3 to 6
Chroma--0 to 2
Texture--silt loam or silty clay loam
Clay content--24 to 35 percent
Sand content--1 to 15 percent
Reaction--slightly alkaline or moderately alkaline
Cg horizon:
Hue--10YR, 2.5Y, or 5Y
Value--3 to 6
Chroma--1 to 3
Texture--silty clay loam; silt loam, or loam
Clay content--24 to 35 percent
Sand content--1 to 35 percent
Reaction--slightly alkaline or moderately alkaline
Some pedons have strata in the Cg horizon that have more clay or more sand
Some pedons have an Ab horizon
COMPETING SERIES: These are the
Badus,
Devilsgait,
Lamo,
Obert,
Salmo,
Sawabash, and
Wingdale series.
Badus--have accumulations of gypsum and other salts within a depth of 150 centimeters
Devilsgate--do not have cambic horizons
Lamo--have a frequently saturated zone at a depth of 0.45 meter during the wettest periods of normal years
Obert--are in areas that have a mean annual precipitation range of 550 to 690 millimeters
Salmo--have segregated nests and crystals of gypsum in the upper two-thirds of the series control section
Sawabash--are in areas that have a mean annual precipitation range of 864 to 1,016 millimeters
Wingdale--are in areas that have a mean annual precipitation range of 230 to 360 millimeters and have layers in the upper third of the series control section that have been influenced by volcanic ash deposition
GEOGRAPHIC SETTING:
Parent material--calcareous alluvium
Landform--floodplains
Slope--0 to 2 percent
Elevation--130 to 500 meters above sea level
Mean annual air temperature--4 to 13 degrees C
Mean annual precipitation--690 to 864 millimeters
Frost-free period--140 to 215 days
GEOGRAPHICALLY ASSOCIATED SOILS: These are the
Colo,
Judson,
Kennebec,
Smithland, and
Zook soils.
Colo--are in landscape positions similar to those of the Calco soils and do not have carbonates within a depth of 150 centimeters
Judson--are at the higher landscape positions on footslopes of uplands and do not have a frequently saturated zone within a depth of 1.8 meters during the wettest periods of normal years
Kennebec--are in landscape positions similar to those of the Calco soils, do not have carbonates within a depth of 150 centimeters, and have a frequently saturated zone at a depth of 0.75 meter during the wettest period of normal years
Smithland--are in landscape positions similar to those of the Calco soils, do not have carbonates within a depth of 150 centimeters, and have a frequently saturated zone at a depth of 0.3 meter during the wettest period of normal years
Zook--are in landscape positions similar to those of the Calco soils and have a clay content that averages 35 to 44 percent in the particle-size control section
DRAINAGE AND SATURATED HYDRAULIC CONDUCTIVITY:
Drainage class--very poorly drained and poorly drained--these soils are frequently saturated at the soil surface during April to June in normal years and is considered apparent
Saturated hydraulic conductivity--1.00 to 10.00 micrometrs per second
Surface runoff potential--negligible to low
Ponding--very poorly drained phase has ponding of up to 0.3 meter for long periods during late winter and spring in normal years and after heavy precipitation events
Flooding--rare to frequent flooding for very brief to long periods during the months of February to November resulting from precipitation events and snowmelt
USE AND VEGETATION:
Most undrained areas are used for pasture. Areas that are artificially drained are cultivated. The principal crops are corn, soybeans, and small grains. The native vegetation is prairie cordgrass, reedgrass, big bluestem, little bluestem and other grasses of the tall grass prairie.
DISTRIBUTION AND EXTENT:
Physiographic Division--Interior Plains
Physiographic Province--Central Lowland
Physiographic sections--Western lake section, Wisconsin driftless section, Till plains, and Dissected till plains
MLRAs--Rolling Till Prairie (102A),
Till Plains (102B,
Loess Uplands (102C),
Central Iowa and Minnesota Till Prairies (103),
Eastern Iowa and Minnesota Till Prairies (104),
Northern Mississippi Valley Loess Hills (105),
Nebraska and Kansas Loess-Drift Hills (106),
Iowa and Missouri Deep Loess Hills (107),
Illinois and Iowa Deep Loess and Drift (108), and
Central Mississippi Valley Wooded Slopes (115)
LRR M; Iowa, southern Minnesota, eastern Nebraska, northeastern Kansas, southeast South Dakota, and Illinois
Extent--large
MLRA OFFICE RESPONSIBLE: St. Paul, Minnesota
SERIES ESTABLISHED: Cass County, Iowa 1967.
REMARKS:
Particle-size control section--the zone from a depth of 25 to 100 centimeters;
series control section--the zone from the surface to a depth of 150 centimeters.
Diagnostic horizons and features recognized in this pedon include:
mollic epipedon--the zone from the surface to a depth of 175 centimeters (Ap, A1, A2, A3, Bg1, Bg2, and BCg horizons);
cambic horizon--the zone from a depth of 97 to 147 centimeters (Bg1 and Bg2 horizons);
aquic moisture regime.
Cation-exchange class is inferred from lab data for similar soils in the surrounding area.
Taxonomy version--Keys to Soil Taxonomy, tenth edition, 2006.
ADDITIONAL DATA:
Laboratory data--Iowa State University, Ames, Iowa pedon number 01IA029001A.