LOCATION MAHKONCE MNEstablished Series
TAXONOMIC CLASS: Fine, smectitic, frigid Aquic Hapludalfs
TYPICAL PEDON: Mahkonce loam, on a plane slope of 1 percent, on a glacial moraine in a deciduous forest. (Colors are for moist soil unless otherwise stated).
A--0 to 4 inches; very dark gray (10YR 3/1) loam; dark gray (10YR 4/1) dry; weak fine granular structure; friable; many fine roots; 2 percent gravel; moderately acid; clear smooth boundary. (2 to 7 inches thick)
E--4 to 9 inches; grayish brown (2.5Y 5/2) fine sandy loam; light brownish gray (2.5Y 6/2) dry; weak thin platy structure; very friable; many fine roots; 2 percent gravel; moderately acid; clear smooth boundary. (0 to 9 inches thick)
Bt1--9 to 18 inches; olive brown (2.5Y 4/4) clay; strong medium angular blocky structure; very firm; common medium roots; many distinct very dark grayish brown (2.5Y 3/2) clay films on faces of peds and in pores; 2 percent gravel; few fine distinct grayish brown (2.5Y 5/2) Fe depletions; slightly acid; clear wavy boundary.
Bt2--18 to 26 inches; olive brown (2.5Y 4/4) clay;strong medium angular blocky structure; very firm; few medium roots; many distinct very dark grayish brown (2.5Y 3/2) clay films on faces of peds and in pores; 2 percent gravel; common medium distinct grayish brown (2.5Y 5/2) Fe depletions and common medium distinct olive yellow (2.5Y 6/6) Fe concentrations; slightly acid; clear wavy boundary. (Combined thickness of the Bt horizons is 8 to 30 inches).
BC--26 to 34 inches; light olive brown (2.5Y 5/4) clay loam; moderate medium subangular blocky structure; firm; few medium roots; common distinct very dark grayish brown (2.5Y 3/2) clay films in old root channels; 6 percent gravel; common medium distinct grayish brown (2.5Y 5/2) Fe depletions and common medium distinct olive yellow (2.5Y 6/8) Fe concentrations; strongly effervescent; moderately alkaline; clear wavy boundary. (0 to 20 inches thick)
C--34 to 60 inches; light olive brown (2.5Y 5/4) clay loam; massive; firm; 5 percent gravel; common medium distinct grayish brown (2.5Y 5/2) Fe depletions and common medium distinct olive yellow (2.5Y 6/8) Fe concentrations; strongly effervescent; moderately alkaline.
TYPE LOCATION: Clearwater County, Minnesota; about 4 miles north of Shevlin; about 2600 feet south and 250 feet east of the northwest corner of Sec. 4, T. 147 N., R. 36 W.
RANGE IN CHARACTERISTICS: The depth to free carbonates typically is 21 to 30 inches but ranges from 15 to 40 inches. Volume of rock fragments, of mixed lithology, ranges from 1 to 8 percent throughout the profile. Cole values are 5.0 to 5.9 in the upper 40 inches of the profile.
The A or Ap horizon has hue of 10YR, value of 2 or 3, and chroma of 1 or 2. It is loam, silt loam, clay loam, or fine sandy loam. Reaction is moderately 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 loam, silt loam, or fine sandy loam. Reaction is moderately acid to neutral.
The Bt horizon has hue of 2.5Y or 10YR, value of 3 to 5, and chroma of 2 to 4. It is clay, silty clay, silty clay loam or clay loam. The percent clay ranges from 35 to 60 percent in the upper part and 30 to 45 percent in the lower part. Clay films are faint to distinct, and few to continuous with chroma of 2 or 3. Reaction is slightly acid to slightly alkaline.
Some pedons have a Bk horizon.
The BC horizon has hue of 2.5Y or 10YR, value of 4 to 6, and chroma of 2 to 4. It is loam, clay loam or silty clay loam. Reaction is neutral to moderately alkaline. Clay films are typically on ped faces or in pores.
The C horizon has hue of 2.5Y or 10YR, value of 4 to 6, and chroma of 2 to 4. It is loam, clay loam or silty clay loam. Reaction is slightly alkaline or moderately alkaline.
COMPETING SERIES: There are no competing series.
GEOGRAPHIC SETTING: The Mahkonce soils are on nearly level or gently sloping slopes on glacial moraines. The slope gradients range from 0 to 4 percent. The soils primarily formed in calcareous glacial till of Late Wisconsin Age. Evidence suggests there has been differential sorting of this till from ice melting, accounting for the silty and clayey nature of some pedons. Mean annual air temperature ranges from 38 to 45 degrees F. Mean annual precipitation ranges from 22 to 25 inches. The frost-free season is about 105 to 130 days. Elevation is about 1150 to 1600 feet.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the Naytahwaush, Auganaush, Cathro and Seelyeville series. The well drained Naytahwaush soils are on convex side slopes, the poorly drained Auganaush soils are in slight depressions and shallow drainageways, and the very poorly drained Cathro and Seelyeville soils are in depressions.
DRAINAGE AND PERMEABILITY: Somewhat poorly drained. Surface runoff is low. Permeability is slow. Depth to the seasonal high saturation is 2.5 feet during the months March to June in normal years.
USE AND VEGETATION: Most areas are in forest or pasture. Some areas are cropped to small grain, hay, or row crops. Native vegetation is mixed hardwoods.
DISTRIBUTION AND EXTENT: MLRA-57 and MLRA-88. Northwestern Minnesota. Inextensive
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: St. Paul, Minnesota
SERIES ESTABLISHED: Mahnomen County, Minnesota, 1992.
REMARKS: Diagnostic horizons and features recognized are: Ochric epipedon - 0 to 9 inches (A and E horizon); Albic horizon - 4 to 9 inches (E horizon); Argillic horizon - 9 to 26 inches (Bt horizons); aquic subgroup based on low chroma redox depletions in the Bt1 horizon.
This soil can be challenged for an Aquertic subgroup classification.
ADDITIONAL DATA: Refer to the Minnesota Agricultural Experiment Station Central File Code number 3958, 4275, 4276, 4346, and 4453 for lab results of laboratory analysis of some pedons of this series.