LOCATION AASTAD                  MN+ND SD

Established Series
Rev. ARG-MGU
03/2014

AASTAD SERIES

The Aastad series consists of very deep, moderately well drained soils that formed in calcareous till on moraines and till plains. Slopes range from 0 to 6 percent. Mean annual precipitation is about 560 millimeters and mean annual air temperature is about 6 degrees C.

TAXONOMIC CLASS: Fine-loamy, mixed, superactive, frigid Pachic Argiudolls

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

Ap--0 to 23 centimeters (about 0 to 9 inches); black (10YR 2/1) clay loam, very dark gray (10YR 3/1) dry; moderate fine and medium subangular blocky structure; firm; about 4 percent coarse fragments; neutral; abrupt smooth boundary.

A--23 to 58 centimeters (about 9 to 23 inches); black (10YR 2/1) clay loam, very dark gray (10YR 3/1) dry; moderate fine and medium subangular blocky structure; firm; about 4 percent coarse fragments; neutral; clear smooth boundary. (Combined thickness of the A horizons is 30 to 60 centimeters)

Bt--58 to 97 centimeters (about 23 to 38 inches); olive brown (2.5Y 4/4) clay loam; moderate medium prismatic structure parting to moderate medium angular blocky; firm; common faint very dark grayish brown (10YR 3/2) clay films on faces of peds; about 4 percent coarse fragments; neutral; clear smooth boundary. (Combined thickness of the Bt horizons is 20 to 60 centimeters)

Bk1--97 to 127 centimeters (about 38 to 50 inches); light olive brown (2.5Y 5/4) clay loam; common medium distinct grayish brown (2.5Y 5/2) redoximorphic depletions and common medium prominent yellowish brown (10YR 5/6) redoximorphic concentrations; moderate medium prismatic structure parting to moderate medium angular blocky; firm; common fine masses of carbonates; about 4 percent coarse fragments; violently effervescent; moderately alkaline; gradual smooth boundary.

Bk2--127 to 163 centimeters (about 50 to 64 inches); grayish brown (2.5Y 5/2) clay loam; many medium distinct light olive brown (2.5Y 5/6) redoximorphic concentration; moderate medium prismatic structure parting to moderate medium angular blocky; firm; common fine masses of carbonates; about 5 percent coarse fragments; violently effervescent; moderately alkaline; gradual smooth boundary. (Combined thickness of the Bk horizon is 20 to 64 centimeters)

BC--163 to 200 centimeters (about 64 to 80 inches); grayish brown (2.5Y 5/2) clay loam; many medium distinct light olive brown (2.5Y 5/6) redoximorphic concentrations; moderate course and extremely course prismatic structure parting to moderate medium and course angular blocky; firm; about 5 percent coarse fragments; strongly effervescent; moderately alkaline.

TYPE LOCATION: Lyon County, Minnesota; 1,824 feet west and 148 feet north of the southeast corner of Sec. 9, T. 112 N., R. 43 W.; USGS Taunton quadrangle; latitude 44 degrees 31 minutes 02 seconds north; longitude 96 degrees 01 minute 36 seconds west, NAD 83.

RANGE IN CHARACTERISTICS:
Thickness of the mollic epipedon: 40 to 60 centimeters
Depth to top of argillic horizon: 30 to 60 centimeters
Depth to secondary carbonates: 45 to 100 centimeters
Depth to redoximorphic features: 75 to 100 centimeters
Stony phases are recognized.

A horizon
Hue: 10YR
Value: 2; 3 dry
Chroma: 1
Texture (less than 2 mm): Loam or clay loam
Clay content: 20 to 35 percent
Rock fragment content: 2 to 12 percent
Reaction: slightly acid to slightly alkaline

Bt horizon
Hue: 10YR or 2.5Y
Value: 2, 3, or 4; 3 or 4 dry
Chroma: 2, 3, or 4
Texture (less than 2 mm): Clay loam
Clay content: 28 to 35 percent
Clay films: Common to many, faint or distinct
Rock fragment content: 2 to 14 percent
Reaction: neutral to slightly alkaline

Bk horizon
Hue: 2.5Y
Value: 4, 5, or 6
Chroma: 2, 3, or 4
Texture (less than 2 mm): Loam or clay loam
Clay content: 24 to 34 percent
Redoximorphic features: Common to many
Secondary carbonates: Common to many, diffuse and segmented
Rock fragment content: 2 to 14 percent
Reaction: slightly to moderately alkaline

BC or C horizon
Hue: 2.5Y
Value: 4, 5, or 6
Chroma: 2, 3, or 4
Texture (less than 2 mm): Loam or clay loam
Redoximorphic features: Common to many
Clay content: 24 to 34 percent
Rock fragment content: 2 to 14 percent
Reaction: slightly to moderately alkaline

COMPETING SERIES: This is the Weetown series. Weetown soils have less than 28 percent clay in the particle size control section.

GEOGRAPHIC SETTING:
Landform(s): Moraines and till plains
Parent material: Calcareous till
Elevation: 270 to 770 meters
Slope range: 0 to 6 percent
Mean annual air temperatures ranges: 2 to 7 degrees C
Mean annual precipitation: 380 to 690 millimeters
Annual frost free season: 110 to 170 days

GEOGRAPHICALLY ASSOCIATED SOILS: These are the Buse, Forman, Brensall, Tress, Balaton, Hamerly, Tonka, Vallers, and Parnell soils. The well drained Buse and Forman soils are on higher landform positions. The moderately well drained Brensall soils are on slightly higher, broad convex flats. The moderately well drained Balaton and somewhat poorly drained Hamerly soils are on lower, slightly convex landform positions. The somewhat poorly drained Tress soils are on lower, more concave landform positions. The poorly drained Vallers soils are on lower landform positions or rims of depressions. The poorly drained Tonka soils are in closed depressions. The very poorly drained Parnell soils are in closed depressions or drainageways.

DRAINAGE AND PERMEABILITY: Moderately well drained. Surface runoff is low to medium depending on slope. Saturated hydraulic conductivity is moderately high, The depth to apparent seasonal high saturation is 75 to 125 centimeters at some time from March to June in normal years.

USE AND VEGETATION: Most areas are cultivated. The main crops are corn and soybeans. Native vegetation is tall grass prairie.

DISTRIBUTION AND EXTENT: Western Minnesota, eastern North Dakota, and northeastern South Dakota. The soils are extensive.

MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: St. Paul, Minnesota.

SERIES ESTABLISHED: Jerauld County, South Dakota, 1950.

REMARKS: Diagnostic horizons and features recognized in this pedon are:
Mollic epipedon - the zone from the surface of the soil to a depth of 58 centimeters (Ap and A horizons)
Argillic horizon - the zone from 58 to 97 centimeters (Bt horizon)
Calcic horizon- the zone from 97 to 163 centimeters (Bk horizons); .

Version of Soil Taxonomy: Keys to Soil Taxonomy, Eleventh Edition, 2010.

ADDITIONAL DATA: Refer to MAES central file code numbers 340, 679, 1293, and 1313 for the results of some laboratory analyses of some pedons that represent this series.

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National Cooperative Soil Survey
U.S.A.