LOCATION PRIMGHAR           IA+MN
Established Series
Rev. CSF-JRW-DBO-AGG
11/2003

PRIMGHAR SERIES


The Primghar series consists of very deep, somewhat poorly drained, moderately permeable soils formed in loess on uplands and high stream benches. Slope ranges from 0 to 5 percent. Mean annual air temperature is about 47 degrees F, and mean annual precipitation is about 27 inches.

TAXONOMIC CLASS: Fine-silty, mixed, superactive, mesic Aquic Hapludolls

TYPICAL PEDON: Primghar silty clay loam - nearly level - cultivated. (Colors are for moist soil unless otherwise stated.)

Ap--0 to 8 inches; black (10YR 2/1) silty clay loam, dark grayish brown (10YR 4/2) dry; weak fine granular structure; friable; moderately acid; clear smooth boundary.

A--8 to 12 inches; black (10YR 2/1) silty clay loam, dark grayish brown (10YR 4/2) dry; weak fine subangular structure; friable; neutral; gradual smooth boundary.

AB--12 to 17 inches; very dark grayish brown (10YR 3/2) silty clay loam, some mixings of very dark grayish brown (2.5Y 3/2) subsoil material in lower part; grayish brown (10YR 5/2) dry; weak fine subangular blocky structure; friable; black (10YR 2/1) coatings on faces of peds; neutral; gradual smooth boundary. (Combined thickness of the A horizon is 16 to 24 inches.)

Bw1--17 to 25 inches; dark grayish brown (2.5Y 4/2) silty clay loam; weak fine subangular blocky structure; friable; few black (10YR 2/1) concretions (manganese oxides); common very dark grayish brown (10YR 3/2) coatings in root channels and on faces of peds; few fine distinct olive brown (2.5Y 4/4) and few fine prominent yellowish brown (10YR 5/6) redox concentrations; neutral; gradual smooth boundary.

Bw2--25 to 36 inches; dark grayish brown (2.5Y 4/2) silty clay loam; weak fine subangular blocky structure; friable; common black (10YR 2/1) concretions (manganese oxides); few fine distinct olive brown (2.5Y 4/4) and few fine prominent yellowish brown (10YR 5/6) redox concentrations; slightly alkaline; gradual smooth boundary.

Bkg--36 to 49 inches; grayish brown (2.5Y 5/2) silt loam; weak coarse subangular blocky structure; friable; common black (10YR 2/1) concretions (manganese oxides); common very pale brown (10YR 8/2) calcium carbonate nodules; many medium distinct light olive brown (2.5Y 5/4) and common fine prominent strong brown (7.5YR 5/6) redox concentrations; strongly effervescent; moderately alkaline; gradual smooth boundary.

Cg--49 to 60 inches; grayish brown (2.5Y 5/2) silt loam; massive; friable; many black (10YR 2/1) concretions (manganese oxides); common very pale brown (10YR 8/2) calcium carbonate accumulations and few very pale brown (10YR 8/2) calcium carbonate nodules; strong brown (7.5YR 5/6)redox concentrations; strongly effervescent; moderately alkaline.

TYPE LOCATION: Cherokee County, about 4 1/2 miles north and 2 miles west of Marcus; about 880 feet south and 410 feet west of the northeast corner of section 7, T. 93 N., R. 42 W.; USGS Granville East, Iowa topographic quadrangle, latitude 42 degrees 53 minutes 35 seconds N, longitude 95 degrees 50 minutes 34 seconds W., NAD27.

RANGE IN CHARACTERISTICS:
Thickness of mollic epipedon: 12 to 24 inches
Depth to carbonates: 24 to 50 inches.
The 10 to 40 inch particle size control section averages between 28 and 35 percent clay and less than 3 percent fine sand and coarser.

Ap, A, and AB horizons:
Hue: 10YR, 2.5Y or is neutral
Value: 2 or 3
Chroma: 0 to 2
Texture: silty clay loam
Reaction: medium acid to neutral

Bw horizon:
Hue: 10YR or 2.5Y
Value: 4 or 5
Chroma: 2 or 3
Texture: silty clay loam or silt loam
Reaction: slightly acid to slightly alkaline.

Bk or Bkg horizon:
Hue: 10YR or 2.5Y
Value: 4 or 5
Chroma: 2 to 4
Texture: silt loam or silty clay loam
Reaction: slightly alkaline or moderately alkaline

C or Cg horizon (where present):
Hue: 10YR or 2.5Y
Value: 4 or 5
Chroma: 2 to 4
Texture: silt loam or silty clay loam with clay content ranging from about 25 to 30 percent
Reaction: slighty alkaline or moderately alkaline

2C or 2Cg horizon (below depths of 60 inches in some pedons):
Hue: 2.5Y or 5Y
Value: 5 or 6
Chroma: 1 or 2
Texture: loam or clay loam
Reaction: slightly alkaline or moderately alkaline
Rock fragment content: 1 to 8 percent by volume
Moist bulk density: 1.6 to 1.8 g/cc

A coarser-textured band as much as 6 inches thick is between the loess and till in most pedons. Terrace phases are recognized. They have 2C horizons of gravel or sand.

COMPETING SERIES:
Amana soils have more variable coarse silt-fine silt ratios having formed in alluvium rather than loess, tend to be more acid, are leached to greater depths, and have distinct silt coats when dry.
Joy soils are lower in clay throughout the solum except for the BC horizon, formed in thicker loess, and have their clay maximum lower in the solum. Kingston soils are lower in clay content in the A and upper B horizons and formed in lacustrine sediments rather than loess.
Klinger and Ransom soils formed in loess and underlying glacial till and have 2B or 2C horizons of loam or clay loam in the control section.
Lakefield soils have formed in lacustrine sediments and contain carbonates within 20 inches of the surface.
McCreath (T) soils formed in 40 to 60 inches of loess and have a lithologic discontinuity in the lower two thirds of the series control section.
Minden soils have a clay maximum of about 32 to 35 percent at a depth of about 2 feet or more. In addition, Minden soils are leached to greater depths. Muscatine soils typically are more acid and are deeper to carbonates. In addition, Muscatine soils commonly have the clay maximum in the Bw horizon.

GEOGRAPHIC SETTING:
Landscape: broad, nearly level to gently sloping upland areas
Slopes: 0 to 5 percent
Parent material: loess
Mean annual air temperature: about 45 to 48 degrees F.
Mean annual precipitation: about 26 to 28 inches.

GEOGRAPHICALLY ASSOCIATED SOILS:
Galva and Sac soils are well drained and are on more sloping parts of the landscape. Marcus soils are poorly drained and are on more nearly level positions

DRAINAGE AND PERMEABILITY:
Drainage: somewhat poorly drained -- seasonal high saturation occurs between 1 and 3.5 feet of the surface during the wettest period of normal years. Permeability: moderate
Surface runoff: low

USE AND VEGETATION: Commonly cropped to corn and soybeans with some small grain and hay. The native vegetation is tall prairie grasses.

DISTRIBUTION AND EXTENT: Northwestern Iowa and southwestern Minnesota. Primghar soils are of moderate extent.

MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Indianapolis, Indiana

SERIES ESTABLISHED: Clay County, Iowa, 1970.

REMARKS: Diagnostic horizons and features recognized in this pedon are: mollic epipedon - zone from the surface to a depth of approximately 17 inches (Ap, A, and AB horizons); cambic horizon - zone from 17 to 49 inches (Bw1, Bw2, and Bkg horizons); udic moisture regime.

ADDITIONAL DATA: Laboratory data are available for the typical pedon through Iowa State University -- lab number 35424-30.

The type location was moved from Clay County, Iowa as it had till above depths of 60 inches. The McCreath series was set up have have till at depths of 40 to 60 inches.


National Cooperative Soil Survey
U.S.A.