LOCATION AUDUBON MN

Established Series
Rev. KAC-JMK-AGG
01/2011

AUDUBON SERIES

The Audubon series consists of very deep, moderately well drained soils that formed in glacial till on moraines. They have slow permeability. Slopes range from 1 to 40 percent. Mean annual precipitation is about 22 inches. Mean annual air temperature is about 40 degrees F.

TAXONOMIC CLASS: Fine, smectitic, frigid Aquic Hapluderts

TYPICAL PEDON: Audubon silty clay with a convex slope of 3 percent on a glacial moraine in a cultivated field. (Colors are for moist soil unless otherwise stated).

Ap--0 to 8 inches; black (10YR 2/1) silty clay, very dark gray (10YR 3/1) dry; strong very fine and fine angular blocky structure; firm; common very fine and fine roots; about 1 percent gravel; neutral; abrupt smooth boundary. (7 to 10 inches thick)

A-- 8 to 14 inches; very dark gray (10YR 3/1) silty clay; strong very fine and fine angular blocky structure; firm; common tongues of black (10YR 2/1) silty clay; common very fine and fine roots; about 1 percent gravel; neutral; clear wavy boundary. (Combined thickness of the A horizons is 7 to 16 inches.)

Bkss--14 to 36 inches; olive brown (2.5Y 4/3) silty clay; moderate fine and medium angular blocky structure; firm; few fine roots; common masses and threads of carbonates; about 1 percent gravel; few slickensides tilted 10 to 60 degrees from horizontal; violently effervescent; moderately alkaline; gradual smooth boundary. (10 to 30 inches.)

C1--36 to 44 inches; light olive brown (2.5Y 5/3) silty clay loam; massive; friable; few fine roots; common medium distinct light olive brown (2.5Y 5/6) Fe concentrations and common medium faint grayish brown (2.5Y 5/2) Fe depletions; strongly effervescent; about 1 percent gravel; slightly alkaline; clear smooth boundary.

C2--44 to 80 inches; olive brown (2.5Y 4/3) silty clay; massive; firm; common medium prominent brown (7.5YR 4/4) Fe concentrations and common medium faint grayish brown (2.5Y 5/2) Fe depletions; about 1 percent gravel; strongly effervescent; slightly alkaline

TYPE LOCATION: Bigstone County, Minnesota; 700 feet west and 100 feet south of the northeast corner Sec. 12, T.122N., R.44W., USGS Wood Lake Minnesota quadrangle, lat. 45 dgrees 23 minutes 55 seconds N. lon. 96 degrees 07 minutes 10 seconds W, NAD27.

RANGE IN CHARACTERISTICS: The mollic epipedon is 7 to 16 inches thick. Free carbonates are at depths of 9 to 20 inches. Rock fragments of mixed lithology make up 1 to 4 percent, by volume, of the profile. The particle size control section has 10 to 20 percent sand, 35 to 50 percent silt, and 35 to 60 percent clay.

The A horizon has hue of 10YR, value of 2 or 3, and chroma of 1 in the upper part and 1 or 2 in the lower part. It is silty clay loam, clay loam, silty clay, or clay. It is neutral or slightly alkaline but has no free carbonates.

The Bkss horizon has hue of 10YR or 2.5Y, value of 4 to 6, and chroma of 3 or 4. It is silty clay loam, clay loam, silty clay, or clay. It is slightly alkaline or moderately alkaline. It has a calcium carbonate equivalent of 20 to 35 percent. Some pedons have a Bw horizon with a hue of 10YR, value of 4, and chroma of 3 or 4 above the Bkss horizon.

The C horizon has hue of 2.5Y, value of 4 through 6 and chroma of 3 or 4. It is silty clay loam, clay loam, silty clay, or clay. It is slightly alkaline or moderately alkaline. It has a calcium carbonate equivalent of 10 to 25 percent.

COMPETING SERIES: This is the Hattie series. The Hattie soils have carbonates to the surface.

GEOGRAPHIC SETTING: These soils are on convex and linear slopes on glacial moraines. Slope gradient ranges from 1 to 40 percent. The soils formed in calcareous glacial till of Late Wisconsin Age. Mean annual precipitation is 20 to 24 inches. Mean annual air temperature is 38 to 42 degrees F. Frost free days range from 90 to 130 days. The elevation above sea level ranges from 1000 to 1600 feet.

GEOGRAPHICALLY ASSOCIATED SOILS: These are the Dovray, Foxlake, Hattie and Boyerlake soils. The moderately well drained Boyerlake soils do not have mollic epipedons. The moderately well drained Hattie soils are calcareous throughout. The very poorly drained Dovray soils are in depressions. The poorly drained Foxlake soils are on low-lying nearly level to concave swales and toeslopes.

DRAINAGE AND PERMEABILITY: Moderately well drained. Surface runoff ranges from slow to rapid. Permeability is slow. Soil saturation (perched water table) occurs as high as depths of 3 feet at some time from October to June in most years.

USE AND VEGETATION: Most of this soil is cultivated. Native vegetation is tall grass prairie.

DISTRIBUTION AND EXTENT: Western Minnesota. Inextensive

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

SERIES ESTABLISHED: Becker County, Minnesota, 1994.

REMARKS: Diagnostic horizons and features identified in this soil are: Mollic epipedon--the zone from the surface to a depth of 14 inches (Ap and A horizons); calcic horizon--the zone from 14 to 36 inches; frigid soil temperature. The presence of some slickensides described in pits is the basis for the taxonomic class. 1/12/2011-TYPE LOCATION error corrected.

These soils are not classic vertisols but this seems to be the best class for them at this time.

ADDITIONAL DATA: For laboratory data see Minn. Ag. Exp. Station CFC No. 4700.

National Cooperative Soil Survey
U.S.A.