LOCATION INDUS MN+WIEstablished Series
TAXONOMIC CLASS: Very-fine, smectitic, frigid Vertic Epiaqualfs
TYPICAL PEDON: Indus clay with a plane level slope on a glacial lake plain in a mixed deciduous and coniferous forest having predominantly quaking aspen. (Colors are for moist soil unless otherwise stated.)
Oe--1.5 to 0.5 inches; dark reddish brown (5YR 2/2) partially decomposed plant remains. (0 to 3 inches thick)
0a--0.5 inches to 0; black (5YR 2/1) well decomposed plant remains. (0 to 2 inches thick)
A--0 to 2 inches; black (10YR 2/1) clay, dark gray (10YR 4/1) dry; moderate very fine and fine granular structure; friable; slightly sticky; common earthworm casts; many fine and very fine roots; slightly acid; abrupt wavy boundary. (1 to 5 inches thick)
Eg--2 to 5 inches; dark gray (10YR 4/1) clay loam, light gray (10YR 7/1) dry; common medium distinct yellowish brown (10YR 5/4) mottles; moderate medium and coarse platy structure; friable; common fine roots; about 15 percent dark grayish brown (2.5Y 4/2) earthworm casts; medium acid; clear wavy boundary. (1 to 8 inches thick)
Btg1--5 to 12 inches; dark gray (5Y 4/1) clay; common fine faint olive gray (5Y 4/2) and distinct olive (5Y 4/4) mottles; strong medium and coarse prismatic structure parting to strong fine and medium angular blocky; very firm; common fine roots; common moderately thick black (10YR 2/1) and very dark gray (5Y 3/1) clay films on faces of peds; thin interfingers of dark gray (5Y 4/1) E material on faces of peds in upper part; medium acid; clear wavy boundary.
Btg2--12 to 19 inches; olive gray (5Y 4/2) clay; moderate medium and coarse prismatic structure parting to moderate very fine and fine angular blocky; very firm; common fine and medium roots; common moderately thick very dark gray (5Y 3/1) clay films on faces of peds and in pores; few slickensides; mildly alkaline; clear smooth boundary. (Combined thickness of the Btg is 9 to 20 inches.)
BC--19 to 23 inches; dark gray (5Y 4/1) clay; common medium faint dark grayish brown (2.5Y 4/2), light gray (2.5Y 7/2) and distinct olive brown (2.5Y 4/4) mottles; moderate fine medium and coarse prismatic structure parting to moderate fine and medium angular blocky; very firm; few fine roots; few thin very dark gray (5Y 3/1) and dark gray (5Y 4/1) clay films on faces of peds; common moderately thick very dark gray (5Y 3/1) and gray (5Y 4/1) clay films lining tubular pores and on prism faces; few slickensides; about 5 percent fine rounded soft masses of lime; slight effervescence; moderately alkaline; clear wavy boundary. (0 to 15 inches thick)
Ckg--23 to 37 inches; olive gray (5Y 5/2) clay; common medium faint olive brown (2.5Y 4/4) mottles; moderate fine, medium, and very coarse prismatic structure that parts to moderate medium angular blocky; firm; few thin dark gray (5Y 4/1) and very dark gray (5Y 3/1) clay films on faces of larger prisms; few 2 to 5 mm lime concretions; about 20 percent light gray (10YR 7/2) large rounded soft lime masses; slight effervescence in matrix, other parts have violent effervescence; moderately alkaline; clear wavy boundary. (0 to 20 inches thick)
Cg--37 to 60 inches; olive gray (5Y 5/2) clay; common medium distinct brown (7.5YR 4/4) and dark yellowish brown (10YR 4/4) mottles; horizontal stratification that breaks to weak fine and medium angular blocks; firm; dark gray (5Y 4/1) in upper parts of plates; strong effervescence; about 8 percent CCE; moderately alkaline.
TYPE LOCATION: Koochiching County, Minnesota; about 3.5 miles north of Loman; about 110 feet east and 2595 feet south of the northwest corner of sec. 26, T. 159 N., R. 25 W.
RANGE IN CHARACTERISTICS: The thickness of the solum and depth to free carbonates ranges from 12 to 35 inches. These soils typically lack coarse fragments, but they have as much as 3 percent of coarse fragments in some pedons. The fragments typically are fine pebble in size and primarily calcium carbonate.
The A horizon has value of 2 or 3. The E horizon has hue of 10YR, 2.5Y, or 5Y; value of 4 through 6; and chroma of 1 or 2. It has faint through prominent mottles in some to all parts. The Ap horizon where present, has value of 3.5 or more. The A and E horizons are clay, silty clay loam, silty clay, clay loam, silt loam, or loam. They are strongly acid through neutral.
The Btg horizon has matrix with hue of 5Y or 2.5Y, value of 4 or 5, and chroma of 1 or 2. It has faint to prominent mottles in some to all parts. It typically is clay throughout with clay contents of 60 to 85 percent, but it has subhorizons in some pedons that are silty clay or silty clay loam. It has thin through thick coatings of E material on faces of peds in the upper part. It is medium acid through neutral in the upper part and neutral through moderately alkaline in the lower part.
The C horizon has hue of 2.5Y or 5Y, value of 4 through 6, and chroma of 1 through 3. It has few through many mottles in at least some part. It is typically clay or silty clay but it has thin strata of silt loam, clay loam or silty clay loam in some pedons. It has slickensides in some pedons. It is moderately alkaline or mildly alkaline.
COMPETING SERIES: No other series is in this family. The Brickton, Effie, and Taylor series are closely related series. Brickton soils typically have thicker sola and are fine textured. Effie soils have less clay in the argillic horizon. Taylor soils typically have 10YR or 2.5Y hue and higher chroma or have chroma of 2 without mottling in the B horizon.
GEOGRAPHIC SETTING: Indus soils have plane and slightly convex slopes in glacial lake plains. Slopes are 0 to 2 percent. They formed in clayey, calcareous glacial lacustrine sediments on glacial lake plains. Mean annual temperature is about 36 to 40 degrees F. Mean annual precipitation is about 21 to 28 inches. The frost-free period is about 100 to 120 days.
GEOGRAPHICALLY ASSOCIATED SOILS: Brickton, Taylor, and Wildwood soils are the main ones. Brickton soils have landscape position and drainage like that of the Indus soils. The Taylor and Wildwood soils formed in similar materials are members of a hydrosequence with the Indus soils. The Taylor soils are moderately well drained and are on higher lying or more sloping terrain. Wildwood soils are very poorly drained and are in depressions.
DRAINAGE AND PERMEABILITY: Poorly and somewhat poorly drained. Surface runoff is slow. Permeability is slow.
USE AND VEGETATION: Most of this soil is forested. A small acreage of this soil is used for pasture, small grain, or hay. Native vegetation was mixed deciduous and coniferous forest. Quaking aspen is presently dominant in most places.
DISTRIBUTION AND EXTENT: Northern Minnesota in glacial lake basins, primarily in the Glacial Lake Agassiz plain. Moderately extensive.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: St. Paul, Minnesota
SERIES ESTABLISHED: Koochiching County, Minnesota, 1971.
REMARKS: Diagnostic horizons and features are: ochric epipedon - the zone from the surface to a depth of 5 inches (A and Eg horizons); albic horizon - the zone from 2 to 5 inches (Eg horizon); argillic horizon - the zone from 5 to 19 inches (Btg1 and Btg2 horizons); aquic moisture regime based upon low chroma of the argillic horizon.
Classification only was changed 5/94. Competing series and other updates will be made later.
ADDITIONAL DATA: Refer to MN. Agr. Exp. Sta. Central file Code No. 885 for results of some laboratory analyses of the typical pedon and to No. 2219 for analyses of another pedon.