LOCATION KOOCH MN

Established Series
GDN-JFG
12/2010

KOOCH SERIES

The Kooch series consists of very deep, somewhat poorly drained soils formed in calcareous glacial till on moraines. These soils have slow permeability. Slopes range from 1 to 4 percent. Mean annual precipitation is about 25 inches. Mean annual air temperature is about 38 degrees F.

TAXONOMIC CLASS: Fine, smectitic, frigid Aquertic Glossudalfs

TYPICAL PEDON: Kooch silt loam, on a convex slope of 1 percent, under mixed aspen forest. (Colors are for moist soil unless otherwise stated.)

A--0 to 3 inches; black (2.5Y 2/1) silt loam, gray (2.5Y 5/1) dry; weak fine granular structure; friable; many fine roots; 1 percent gravel; slightly acid; abrupt smooth boundary. (2 to 6 inches thick)

E--3 to 5 inches; light brownish gray (2.5Y 6/2) silt loam; weak fine subangular blocky structure; friable; many fine and medium roots; 1 percent gravel; moderately acid; gradual wavy boundary. (0 to 9 inches thick)

E/B--5 to 11 inches; about 60 percent light brownish gray (2.5Y 6/2) (E) silt loam; about 40 percent light olive brown (2.5Y 5/4) (B) clay; moderate medium subangular blocky structure; friable; common fine and medium roots; few faint dark grayish brown (2.5Y 4/2) clay films on faces of peds and in pores; 2 percent gravel; moderately acid; gradual wavy boundary. (0 to 8 inches thick)

Bt1--11 to 17 inches; olive brown (2.5Y 4/4) clay; few fine distinct grayish brown (2.5Y 5/2) and common fine prominent dark yellowish brown (10YR 4/6) Fe concentrations; strong medium angular blocky structure; very firm; common medium roots throughout; common distinct dark grayish brown (2.5Y 4/2) clay films on faces of peds and in pores; 3 percent gravel; slightly acid; clear smooth boundary.

Bt2--17 to 22 inches; olive brown (2.5Y 4/4) silty clay; many fine distinct grayish brown (2.5Y 5/2) Fe depletions and few fine prominent dark yellowish brown (10YR 4/6) Fe concentrations; moderate fine subangular blocky structure; firm; common medium roots; common distinct dark grayish brown (2.5Y 4/2) clay films on faces of peds and in pores; 3 percent gravel; slightly acid; clear smooth boundary. (Combined thickness of the Bt horizon is 7 to 28 inches.)

Cg1--22 to 46 inches; dark grayish brown (2.5Y 4/2) silty clay; common medium distinct light olive gray (5Y 6/2) Fe depletions and few fine prominent olive yellow (5Y 6/6) Fe concentrations; massive; firm; common medium roots; 3 percent gravel; strongly effervescent; moderately alkaline; clear smooth boundary.

Cg2--46 to 80 inches; grayish brown (2.5Y 5/2) silty clay loam; common medium distinct light olive gray (5Y 6/2) Fe depletions and common fine prominent olive yellow (5Y 6/6) Fe concentrations; massive; firm; few medium and coarse roots; 3 percent gravel; medium irregular light gray (2.5Y 7/1) soft masses of carbonate throughout; violently effervescent; moderately alkaline.

TYPE LOCATION: Koochiching County, Minnesota; about 2 miles north and 2 miles east of Ray; located about 1,600 feet south and 400 feet east of northwest corner of section 22, T. 69 N., R. 22 W.; USGS Ray topographic quadrangle; lat. 48 degrees 27 minutes 19 seconds N. and long. 93 degrees 09 minutes 18 seconds W., NAD 83.

RANGE IN CHARACTERISTICS: The depth to carbonates ranges from 18 to 38 inches. The series control section averages 35 to 60 percent clay. Rock fragments of mixed lithology range from 1 to 8 percent by volume. Aquic conditions occur at a depth of 12 to 24 inches in most years.

Some pedons have an O horizon 1 to 3 inches thick. The O horizon is partially to well decomposed organic matter from remains of trees, shrubs, sedges, and forest floor flora. It has a hue of 10YR or 2.5Y, value of 1 to 3, and chroma of 1 or 2.

The A horizon has hue of 10YR or 2.5Y, value of 2 or 3, chroma of 1 or 2. It is silt loam, loam, silty clay loam, or very fine sandy loam. It is strongly acid to neutral.

The E horizon has hue of 10YR or 2.5Y, value of 4 to 6, and chroma of 1 to 3. It is silt loam, loam, sandy clay loam, silty clay loam, or very fine sandy loam. It is strongly acid to neutral.

The E/B horizon has characteristics similar to the E horizon and the Bt horizon

Some pedons have a B/E horizon.

The Bt horizon has hue of 10YR or 2.5Y, value of 3 to 5, and chroma of 2 to 4. Texture is silty clay, clay, or silty clay loam. It is strongly acid to neutral.

Some pedons have a BC or Bk horizon.

The C horizon has hue of 2.5Y or 5Y, value of 4 to 6, and chroma of 1 to 4. It is clay, silty clay, or silty clay loam. Soft threads or rounded and irregular masses of calcium carbonate are in many pedons. It is slightly alkaline or moderately alkaline.

COMPETING SERIES: This is the Ashlake series. Ashlake soils have less then 35 percent clay in the lower third of the series control section.

GEOGRAPHIC SETTING: Kooch soils are on slightly convex to plane surfaces on ground moraines. Slopes range from 1 to 4 percent. They formed in calcareous glacial till. Mean annual air temperature ranges from 36 to 40 degrees. Mean annual precipitation ranges from 23 to 28 inches. The frost-free period ranges from 90 to 120 days.

GEOGRAPHICALLY ASSOCIATED SOILS: These are the Kab, Haystore, Ratroot and Dora series. Poorly drained Kab soils are on plane or slightly concave surfaces on slightly lower lying positions. Moderately well drained Haystore soils are on convex higher lying positions. Very poorly drained Ratroot soils are in lower lying concave positions. Very poorly drained Dora soils formed in organic material over clayey sediments and are in lower lying concave positions.

DRAINAGE AND PERMEABILITY: Somewhat poorly drained. Surface runoff is low to medium. Permeability is slow. A perched water table is at a depth of 1.0 to 2.0 feet sometime during the period April to July in normal years.

USE AND VEGETATION: Most of this soil is forested. Aspen, fir and spruce are common species. Some areas are cleared and used for production of hay, small grains, and pasture.

DISTRIBUTION AND EXTENT: North central Minnesota, MLRA-88 and 93; Moderate extent.

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

SERIES ESTABLISHED: Koochiching County, Minnesota, 2010. The name comes from a historic town in the county.

REMARKS: Diagnostic horizons and features recognized in this pedon include: ochric epipedon - the zone from the surface to 3 inches (A horizon); albic horizon - the zone from 3 to 5 inches (E horizon); glossic horizon - the zone from 5 to 11 inches (E/B horizon); argillic horizon - the zone from 11 to 22 inches (Bt1 and Bt2 horizons).

National Cooperative Soil Survey
U.S.A.