LOCATION PRIMGHAR                IA+MN

Established Series
Rev. CSF-JRW-DBO-DJP
08/2017

PRIMGHAR SERIES

The Primghar series consists of very deep, somewhat poorly drained soils formed in loess on uplands and high stream benches. Slope ranges from 0 to 5 percent. Mean annual air temperature is about 8 degrees C (47 degrees F), and mean annual precipitation is about 690 millimeters (27 inches).

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

TYPICAL PEDON: Primghar silty clay loam, on a nearly level slope in a cultivated field. (Colors are for moist soil unless otherwise stated.)

Ap--0 to 20 centimeters (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--20 to 30 centimeters (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--30 to 43 centimeters (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 Ap, A, and AB horizon is 41 to 61 centimeters (16 to 24 inches).]

Bw1--43 to 64 centimeters (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--64 to 91 centimeters (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--91 to 124 centimeters (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--124 to 152 centimeters (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 masses and few very pale brown (10YR 8/2) calcium carbonate nodules; prominent strong brown (7.5YR 5/6) redox concentrations; strongly effervescent; moderately alkaline.

TYPE LOCATION: Land Resource Unit (LRU) 107A (Iowa and Minnesota Loess Hills); 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; lat. 42 degrees 53 minutes 35 seconds N. and long. 95 degrees 50 minutes 34 seconds W., NAD27.

RANGE IN CHARACTERISTICS:
Thickness of the mollic epipedon--30 to 61 centimeters (12 to 24 inches)
Depth to carbonates--61 to 127 centimeters (24 to 50 inches)
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: moderately 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 20 to 30 percent
Reaction: slightly alkaline or moderately alkaline

2C or 2Cg horizon (where present below the series control section or depths of 150 centimeters):
Hue: 2.5Y or 5Y
Value: 5 or 6
Chroma: 1 or 2
Texture: loam or clay loam
Rock fragment content: 1 to 8 percent by volume
Moist bulk density: 1.6 to 1.8 g/cc
Reaction: slightly alkaline or moderately alkaline

A coarser-textured band as much as 15 centimeters (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: These are the Amana, Breeds, Grantcenter, Joy, Joyce, Kingston, Klinger, Klingmore, Lakefield, Larpenteur, McCreath, Muscatine, Nerwoods, Okabena, and Ransom series.
Amana--are deeper than 127 centimeters to carbonates
Breeds--have a paralithic contact in the lower part of the series control section
Grantcenter--average more than 3 percent fine sand and coarser in the particle-size control section
Joy--average less than 28 percent clay in the particle-size control section
Joyce--average less than 28 percent clay in the particle-size control section
Kingston--average more than 3 percent fine sand and coarser in the particle-size control section
Klinger--average more than 3 percent fine sand and coarser in the particle-size control section
Klingmore--average more than 3 percent fine sand and coarser in the particle-size control section
Lakefield--have carbonates within a depth of 61 centimeters
Larpenteur--average more than 3 percent fine sand and coarser in the particle-size control section
McCreath--have a lithologic discontinuity (till) in the lower part of the series control section
Muscatine--have a Btg horizon within the series control section
Nerwoods--have a lithologic discontinuity (till) in the lower part of the series control section
Okabena--have a lithologic discontinuity (till) in the lower part of the series control section
Ransom--have a lithologic discontinuity (till) in the lower part of the series control section

GEOGRAPHIC SETTING:
Landscape: broad upland areas and high stream benches
Slopes: 0 to 5 percent
Parent material: loess
Mean annual air temperature: about 7 to 9 degrees C (45 to 48 degrees F)
Mean annual precipitation: about 660 to 710 millimeters (26 to 28 inches)

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

DRAINAGE AND SATURATED HYDRAULIC CONDUCTIVITY:
Drainage class--somewhat poorly drained--seasonal high saturation occurs between 0.3 and 1.0 meter (1 and 3.5 feet) of the surface during the wettest period of normal years
Saturated hydraulic conductivity-0.10 to 10.00 micrometers per second
Permeability--moderate
Surface runoff--low

USE AND VEGETATION:
Most areas are cultivated. The principal crops are corn and soybeans with some small grain and hay. The native vegetation is tall prairie grasses.

DISTRIBUTION AND EXTENT:
LRR--M; LRUs 107A and 102C; northwestern Iowa and southwestern Minnesota
Extent--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:
Particle-size control section--the zone from a depth of 25 to 100 centimeters (A, AB, Bw1, Bw2, Bkg horizons).
Series control section--the zone from the surface to a depth of 150 centimeters (Ap, A, AB, Bw1, Bw2, Bkg, Cg horizons).
Mollic epipedon--the zone from the surface to a depth of 43 centimeters (17 inches) (Ap, A, AB horizons).
Cambic horizon--the zone from 43 to 124 centimeters (17 to 49 inches) (Bw1, Bw2, Bkg horizons).
Udic moisture regime.

Taxonomy version--Keys to Soil Taxonomy, Twelfth edition, 2014.

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

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National Cooperative Soil Survey
U.S.A.