LOCATION SOO                MI
Established Series
Rev.GDW-WEF
02/2003

SOO SERIES


The Soo series consists of very deep, poorly drained and very poorly drained soils formed in loamy lacustrine deposits on lake plains. Permeability is slow. Slopes range from 0 to 2 percent. Mean annual precipitation is about 31 inches and mean annual temperature is about 40 degrees F.

TAXONOMIC CLASS: Fine-silty, mixed, superactive, nonacid, frigid Aeric Epiaquents

TYPICAL PEDON: Soo silty clay loam in a cultivated field. (Colors are for moist soil unless otherwise stated.)

Ap--0 to 7 inches; very dark gray (10YR 3/1) silty clay loam; gray (10YR 6/1) dry; moderate medium subangular blocky structure parting to moderate medium granular; friable; many fine to coarse roots; common medium prominent brownish yellow (10YR 6/8) and strong brown (7.5YR 5/8) iron accumulations throughout; slightly acid; clear smooth boundary. (6 to 9 inches thick)

Bw--7 to 17 inches; dark brown (7.5YR 4/4) silty clay loam; very coarse angular blocky structure; very firm; common fine and few coarse roots; common medium distinct strong brown (7.5YR 5/6) iron accumulations and common fine prominent gray (5YR 5/1) iron depletions throughout; slightly alkaline; clear wavy boundary. (6 to 18 inches thick)

C1--17 to 26 inches; reddish brown (5YR 5/3) silty clay loam with thin bands of pinkish gray (5YR 7/2) silt loam; weak thick platy fragments; firm; few fine roots; greenish gray (5GY 6/1) clay films in root channels; common medium prominent strong brown (7.5YR 5/8) and yellowish brown (10YR 5/6) iron accumulations throughout; violently effervescent; moderately alkaline; clear smooth boundary.

C2--26 to 60 inches; reddish brown (5YR 5/3) silty clay loam with thin bands of pinkish gray (5YR 7/2) silt loam; massive; firm; few fine roots in the upper 20 inches; greenish gray (5GY 6/1) silt coatings in root channels; few medium prominent brownish yellow (10YR 6/6) iron accumulations throughout; violently effervescent; moderately alkaline.

TYPE LOCATION: Chippewa County, Michigan; about 3 miles southwest of Rudyard; 450 feet south and 2,200 feet west of the northeast corner of sec. 22, T. 44 N., R. 3 W.

RANGE IN CHARACTERISTICS: Solum depth and depth to free carbonates ranges from 15 to 25 inches. The particle size control section averages from 18 to 40 percent clay and less than 50 percent fine sand or coarser.

The Ap horizon has hue of 7.5YR or 10YR, value of 2 or 3, and chroma of 1 or 2. Some areas have an A horizon with similar colors. It is silty clay loam or silt loam. Reaction of the Ap is slightly acid or neutral.

The Bw horizon has hue of 5YR or 7.5YR, and value and chroma of 3 or 4. Reaction ranges from slightly acid to slightly alkaline.

The C horizons have hue of 5YR or 7,5YR, value of 4 to 7, and chroma of 2 to 6. It is predominantly silty clay loam with thin bands of silt loam, silt, and silty clay. Reaction is moderately alkaline.

COMPETING SERIES: There are no other series in the same family. Closely related are the Brickton, Bruce, and Pickford series. The Brickton and Pickford soils contain more than 40 percent clay in the control section. In addition, the Brickton soils have grayer colors and have argillic horizons. The Bruce soils contain more than 50 percent fine or coarser sand in the particle size control section and have darker surfaces.

GEOGRAPHIC SETTING: Soo soils occupy nearly level to depressional areas on lake plains. Slopes are less than 2 percent. Mean annual precipitation is about 28 to 33 inches and the mean annual air temperature is about 41 to 43 degrees F.

GEOGRAPHICALLY ASSOCIATED SOILS: These are the Bowers, Fibre, and Pickford soils. The Soo soil is in a drainage sequence with the somewhat poorly drained Bowers soil. The Fibre and Pickford soils are on similar landscape positions. Fibre soils have sandy surfaces and subsoils and Pickford soils have 35 to 60 percent clay.

DRAINAGE AND PERMEABILITY: Poorly drained and very poorly drained. The soil has a perched seasonal high water table that ranges from 1 foot above the surface to 1 foot below the surface at times during the period from October to June. Runoff is very slow or ponded. Permeability is slow.

USE AND VEGETATION: Most areas are used for pasture, hay, small grains, and woodland. Common tree species are quaking aspen, balsam fir, paper birch, white spruce and red maple.

DISTRIBUTION AND EXTENT: Eastern Upper Peninsula of Michigan. The series is of moderate extent.

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

SERIES ESTABLISHED: Chippewa County, Michigan, 1989.

REMARKS: Diagnostic horizons and features recognized in this pedon are: ochric epipedon - the zone from 0 to 7 inches; cambic horizon - the zone from 7 to 17 inches; Aeric feature - hue of 7.5YR or redder and chroma of 2 or more on 50 percent or more of ped exteriors; aquic moisture regime - Classification to the Aquept suborder is tentative based on a positive reaction to alpha-alpha dipyridyl.

ADDITIONAL DATA: For data on representative pedon refer to Michigan Technological University pedon, S84-26-033-005. Soil Interpretation Record No.: MI0543


National Cooperative Soil Survey
U.S.A.