LOCATION POTAGANNISSING MIEstablished Series
TAXONOMIC CLASS: Loamy, mixed, superactive, frigid Lithic Hapludolls
TYPICAL PEDON: Potagannissing gravelly silt loam on a 1 percent slope in native grasslands. (Colors are for moist soil unless otherwise stated.)
A--0 to 4 inches; very dark gray (10YR 3/1) gravelly silt loam, dark grayish brown (10YR 4/2) dry; moderate medium granular structure; friable; many fine and medium roots; about 20 percent gravel and 5 percent cobbles; mildly alkaline; clear smooth boundary. (4 to 5 inches thick)
C--4 to 7 inches; yellowish brown (10YR 5/4) gravelly fine sandy loam; few fine distinct pale brown (10YR 6/3) and common medium distinct yellowish brown (10YR 5/6 and 10YR 5/8) mottles; weak medium granular structure; friable; few fine roots; very dark gray (10YR 3/1) worm mixing in 20 percent of the horizon; about 10 percent gravel and 5 percent cobbles; moderately alkaline; abrupt smooth boundary. (1 to 5 inches thick)
2R--7 inches; limestone bedrock.
TYPE LOCATION: Chippewa County, Michigan; Drummond Island on the Maxton Plains; 1500 feet west and 575 feet north of the southeast corner, sec. 31, T. 43 N., R. 7 E.
RANGE IN CHARACTERISTICS: The depth to bedrock is 5 to 10 inches. Reaction is neutral to moderately alkaline. Textures through the pedon are silt loam, fine sandy loam, loam, very fine sandy loam, or the gravelly or cobbly analogs of these textures. Gravel content ranges from 5 to 15 percent by volume and cobble content ranges from 0 to 20 percent. Rock fragments are dominantly limestone but also include granites.
The A horizon has value of 2 or 3 and chroma of 1 to 3. Some areas have thin organic layers on the surface. Some pedons have a thin Bw horizon with hue of 7.5YR or 10YR, value and chroma of 3 or 4.
The C horizon has value of 5 or 6 and chroma of 2 to 6.
COMPETING SERIES: These are the Ansari, Corpening, Falcon, Kloten and Namur soils in the same family and the Ensign, Romeo and Ruse series. The Ansari, Corpening, Falcon, Kloten and Namur soils do not have mottles in their profiles and are well drained. In addition Ansari soils have redder hue, are underlain by sandstone and have a consistent k horizon. Corpening and Falcon soils are usually dry. Kloten soils have grayer hue and have formed in shale. Ensign and Ruse soils are underlain by bedrock at depths of 10 to 20 inches. In addition Ruse soils are poorly drained. Romeo soils are mesic.
GEOGRAPHIC SETTING: Potagannissing soils are on nearly level ground moraines or glacial lake benches. Slope gradients range from 0 to 3 percent. Mean annual precipitation ranges from 26 to 33 inches, and mean annual temperature ranges from 41 to 44 degrees F.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the Ensign, Ruse, and Summerville soils. These soils are underlain by limestone bedrock at 10 to 20 inches. The somewhat poorly drained Ensign soils are on similar landscape positions, and the poorly drained Ruse soils are in depressions or drainageways. The well drained Summerville soils are on higher landscape positions.
DRAINAGE AND PERMEABILITY: Somewhat poorly drained. Surface runoff is slow. Permeability is moderate.
USE AND VEGETATION: The Maxton Plains area is a unique bedrock grasslands area with some rare plants such as little bluestem, prairie smoke, and prairie dropseed associated with thin soils on limestone bedrock. Other areas are wooded with small openings. Major tree vegetation is northern whitecedar, balsam fir, and quaking aspen.
DISTRIBUTION AND EXTENT: Drummond Island, Michigan; possibly central and eastern Upper Peninsula and the northern part of lower Michigan. This series is of small extent.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: St. Paul, Minnesota
SERIES ESTABLISHED: Chippewa County, Michigan, 1985.
REMARKS: Classification of loamy, mixed Lithic Haploborolls is justified based on the lack of a histic epipedon, mottling in the mollic epipedon, or gray colors immediately below the mollic epipedon. Also, the natural vegetation of the area indicates more of the somewhat poorly drained soil condition rather than a poorly drained (aquic) condition. Diagnostic horizons and features recognized in this pedon are: mollic epipedon - the zone from the surface to 7 inches (after mixing); a lithic contact at 7 inches (2R).