LOCATION COOPER IA+MO NEEstablished Series
TAXONOMIC CLASS: Fine-silty over clayey, mixed, superactive, mesic Fluvaquentic Hapludolls
TYPICAL PEDON: Cooper silty clay loam, on a slope of about 1 percent, on a flood plain, in a cultivated field, at an elevation of 975 feet above sea level. (Colors are for moist soil unless otherwise stated.)
Ap--0 to 8 inches; very dark brown (10YR 2/2) silty clay loam, dark grayish brown (10YR 4/2) dry; weak fine subangular blocky and granular structure; friable; neutral; gradual smooth boundary.
A--8 to 16 inches; very dark brown (10YR 2/2) silty clay loam, dark grayish brown (10YR 4/2) dry; weak fine subangular blocky structure; friable; neutral; gradual smooth boundary. (Combined thickness of the A horizons is 10 to 20 inches.)
Bg--16 to 24 inches; dark grayish brown (10YR 4/2) silty clay loam; weak fine subangular blocky structure; friable; slightly alkaline; abrupt smooth boundary. (6 to 12 inches thick)
2Ab--24 to 33 inches; very dark gray (10YR 3/1) silty clay; strong fine subangular blocky structure; very firm; few calcium carbonate concretions; slightly effervescent; moderately alkaline; gradual smooth boundary. (0 to 13 inches thick)
2Cg--33 to 60 inches; olive gray (5Y 4/2) silty clay; olive gray (5Y 5/2) coatings on faces of some peds; massive with vertical cleavage; very firm; many calcium carbonate concretions; few fine prominent yellowish brown (10YR 5/4) redoximorphic concentrations; strongly effervescent; moderately alkaline.
TYPE LOCATION: Pottawattamie County, Iowa; about 4 miles south and 2 miles east of Council Bluffs; about 150 feet south and 2,100 feet east of the northwest corner of sec. 32, T. 74 N., R. 43 W.; USGS Council Bluffs South quadrangle; lat. 41 degrees 10 minutes 26 seconds N. and long. 95 degrees 48 minutes 55 seconds W., NAD 27
RANGE IN CHARACTERISTICS:
Depth to carbonates--20 to 40 inches
Depth to the cambic horizon--10 to 20 inches
Depth to clayey alluvium--20 to 30 inches
Thickness of the cambic horizon--6 to 30 inches
Content of clay in the upper two thirds of the particle-size control section (weighted average)--27 to 34 percent
Content of clay in the lower one third of the particle-size control section (weighted average)--40 to 60 percent
Content of sand in the particle-size control section (weighted average)--1 to 15 percent fine sand and sand coarser than fine sand
Ap horizon:
Hue--10YR
Value--2
Chroma--1 or 2
Texture--silty clay loam, silt loam, or loam
Clay content--24 to 34 percent
Sand content--10 to 35 percent
Calcium carbonate equivalent--0 to 15 percent
Reaction--slightly acid to slightly alkaline
A horizon:
Hue--10YR
Value--2
Chroma--1 to 3
Texture--silty clay loam
Clay content--27 to 34 percent
Sand content--10 to 20 percent
Calcium carbonate equivalent--0 to 15 percent
Reaction--slightly acid to slightly alkaline
BA horizon (if it occurs):
Hue--10YR or 2.5Y
Value--3
Chroma--2
Texture--silty clay loam
Clay content--27 to 34 percent
Sand content--10 to 20 percent
Calcium carbonate equivalent--0 to 25 percent
Reaction--neutral or slightly alkaline
Bg horizon:
Hue--10YR or 2.5Y
Value--4 or 5
Chroma--2
Texture--silty clay loam
Clay content--27 to 34 percent
Sand content--10 to 20 percent
Calcium carbonate equivalent--0 to 25 percent
Reaction--neutral or slightly alkaline
2Ab horizon:
Hue--10YR to 5Y
Value--3
Chroma--1 or 2
Texture--silty clay or clay
Clay content--40 to 60 percent
Sand content--1 to 10 percent
Calcium carbonate equivalent--0 to 25 percent
Reaction--slightly alkaline or moderately alkaline
2Bg, 2Bkg, or 2BCg horizon (if they occur):
Hue--10YR to 5Y
Value--4 or 5
Chroma--1 or 2
Texture--silty clay or clay
Clay content--40 to 60 percent
Sand content--1 to 10 percent
Calcium carbonate equivalent--5 to 25 percent
Reaction--slightly alkaline or moderately alkaline
2Cg horizon:
Hue--10YR to 5Y
Value--4 to 6
Chroma--2
Texture--silty clay or clay
Clay content--40 to 60 percent
Sand content--1 to 10 percent
Calcium carbonate equivalent--5 to 25 percent
Reaction--slightly alkaline or moderately alkaline
Some pedons have 3Cg horizons below 60 inches with textures of silty clay loam or silt loam
COMPETING SERIES: There are no competing series.
GEOGRAPHIC SETTING:
Parent material--20 to 30 inches of silty alluvium and the underlying clayey alluvium
Landform--flood plains
Slopes--0 to 2 percent
Elevation--700 to 1,200 feet above sea level
Mean annual air temperature--47 to 53 degrees F.
Mean annual precipitation--25 to 32 inches
Frost-free period--140 to 160 days
GEOGRAPHICALLY ASSOCIATED SOILS: These are the
Blencoe,
Blend,
Keg,
Luton, and
Salix soils.
Blencoe--are at the slightly lower elevations and have 18 to 24 percent clay in the lower part of the series control section
Blend--are in similar landscape positions to those of the Cooper soils and have a saturated within a depth of 1 foot during March to June in most years
Keg--are at the higher elevations and have 18 to 26 percent clay in the particle-size control section
Luton--are at the lower elevations and have 40 to 75 percent clay in the upper part of the particle-size control section
Salix--are at the slightly higher elevations and have 16 to 22 percent clay in the lower part of the particle-size control section
DRAINAGE AND PERMEABILITY:
Drainage class--somewhat poorly drained--a saturated zone occurs within a depth of 1 to 3 feet during April to June in most years and is considered apparent
Permeability--moderate in the upper part and slow in the lower part
Surface runoff potential--low
Flooding--rarely flooded for brief periods during the months of February to November resulting from precipitation events and snowmelt
USE AND VEGETATION:
Most areas are cultivated. Corn and soybeans are the principal crops. Some areas are irrigated. The native vegetation is big bluestem, indiangrass, switchgrass, and other grasses of the tall grass prairie.
DISTRIBUTION AND EXTENT:
LRR M, MLRA 107; along the Missouri River about midway between the river channel and the upland foot slopes in Iowa and possibly adjoining states. This series is of small extent.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Indianapolis, Indiana
SERIES ESTABLISHED: Monona County, Iowa, 1951.
REMARKS:
Diagnostic horizons and features recognized in this pedon:
particle-size control section--the zone from a depth of 10 to 40 inches (A, Bg, 2Ab, and 2Cg horizons);
series control section--the zone from the surface to a depth of 60 inches (Ap, A, Bg, 2Ab, and 2Cg horizons);
mollic epipedon--the zone from the surface to a depth of 16 inches (Ap and A horizons);
cambic horizon--the zone from a depth of 16 to 24 inches (Bg horizon);
udic moisture regime.
Cation-exchange class is inferred from lab data for similar soils in the surrounding area.
Taxonomy version--Second Edition, 1999.
The classification of the Cooper series has been changed from Aquic Hapludolls to Fluvaquentic Hapludolls because the typical pedon has a buried mollic horizon below a cambic horizon.