LOCATION FROBERG MIEstablished Series
TAXONOMIC CLASS: Clayey over loamy, mixed, semiactive, frigid Oxyaquic vertic Hapludalfs
TYPICAL PEDON: Froberg silt loam - on a 4 percent slope - forested. (Colors are for moist soil unless otherwise stated.)
Ap--0 to 4 inches; dark brown (7.5YR 3/3) clay; moderate fine and medium granular structure; firm; many very fine to coarse roots; moderately acid; abrupt smooth boundary. (3 to 6 inches thick)
B/E--4 to 8 inches; reddish brown (5YR 4/4) clay; weak coarse angular blocky parting to moderate fine and medium angular blocky structure; very firm; many very fine to coarse roots; many reddish brown (5YR 4/4) clay films and many prominent brown (7.5YR 4/3) organoargillans on all faces of peds; moderately acid; clear wavy boundary. (0 to 5 inches thick)
Bt--8 to 22 inches; reddish brown (5YR 4/4) clay; weak coarse prismatic parting to moderate fine and medium subangular blocky structure; very firm; many fine to coarse roots; few reddish brown (5YR 4/4) clay films; neutral; gradual wavy boundary. (Combined thickness of the Bt horizon is 8 to 25 inches)
BC1--22 to 32 inches; reddish brown (5YR 4/4) clay; weak very coarse subangular blocky parting to moderate fine and medium subangular blocky structure; firm; many fine to coarse roots; many reddish brown (5YR 4/4) clay films; about 3 percent cobbles and 10 percent gravel; slight effervescence; moderately alkaline; clear wavy boundary.
2BC2--32 to 45 inches; reddish brown (5YR 4/4) gravelly sandy clay loam; weak coarse subangular blocky structure; friable; few fine to coarse roots; common reddish brown (5YR 4/4) clay films; few strong brown (7.5YR 5/6) masses of oxidized iron; about 5 percent cobbles and 10 percent gravel; very slight effervescence; moderately alkaline; gradual wavy boundary.
2BC3--45 to 80 inches; reddish brown (5YR 4/4) sandy clay loam and pockets of gravelly loamy fine sand, loam and clay loam; weak coarse subangular blocky structure; friable; few fine and medium roots; few reddish brown (5YR 4/4) clay films; few dark red (2.5YR 3/6) masses of oxidized iron; about 5 percent gravel; very slight effervescence; moderately alkaline; clear wavy boundary.
TYPE LOCATION: Ontonagon County, Michigan; about 3.7 miles north of Bruce Crossing, 1349 feet south and 247 feet west of the northeast corner of section 4, T. 48 N., R. 39 W.
RANGE IN CHARACTERISTICS: The thickness of the clayey sediments ranges from about 15 to 36 inches. The solum ranges from strongly acid to slightly acid in the upper part and from strongly acid to slightly alkaline in the lower part; some pedons contain free carbonates. The 2C horizon ranges from strongly acid to slightly acid. Gravel and cobble content ranges from 0 to 3 percent in the 2C horizon.
Some pedon have Oe and/or Oa horizons composed of partially decomposed or well decomposed forest litter.
The Ap horizon has hue of 5YR or 7.5YR, value of 3 or 4, and chroma of 2 or 3. It is silt loam, silty clay loam, clay loam or clay. Where present, the A horizon has hue of 5YR to 10YR, value of 2 to 4, and chroma of 1 to 3, or is neutral with value of 2 to 4. Where present, the E horizon has a hue of 5YR or 7.5YR, value of 5 or 6, and chroma of 2 or 3. The A and E horizons are silt loam or silty clay loam.
The B part of the B\E horizon have chroma of 3 to 6. They are silty clay loam, silty clay or clay. The E part has a hue of 5YR or 7.5YR, value of 5 or 6, and chroma of 2 or 3. It is silt loam or silty clay loam.
The Bt and BC horizons have chroma of 3 to 6. They are silty clay or clay. Clay content in the Bt or BC horizons ranges from 40 to 80 percent. The 2Bt or 2BC horizons has hue of 10R or 2.5YR, value of 3 or 4, and chroma of 4 or 6. It ranges from sandy loam to sandy clay loam. Some pedons do not have a BC horizon.
Some pedons have a 2C horizon. The 2C horizon has hue of 5YR to 10R, value of 4 or 5, and chroma of 4 or 5. It is sandy loam, fine sandy loam, or sandy clay loam.
COMPETING SERIES: There are no other series in the same family. Similar or related soils include Dighton, Hibbing, Sent, Nester, Nunica, Ontonagon, and Watton. Dighton soils have coarser textured upper sola. Hibbing, Kent, Nester, and Watton soils formed in glacial till, have a coarser textured upper sola, and do not have sandy loam in the lower part of the solum. Nunica soils formed in coarser textured lacustrine sediments and have a coarser textured solum. Ontonagon soils are very-fine and do not have sandy loam or sandy clay loam 2C horizons.
GEOGRAPHIC SETTING: Froberg soils are on nearly level to gently sloping areas of lake plains. They are also on steep slopes of water coarses that dissect the lake plains. Slopes range from 0 to 35 percent. Annual precipitation ranges from 28 to 33 inches. The mean annual temperature is about 40 to 45 degrees F., and the mean summer temperature is 60 to 67 degrees F.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the well drained or moderately well drained Ontonagon and Munising soils and the somewhat poorly drained Rudyard soils. The Ontonagon and Munising soils are on similar landscape positions and the Rudyard soils are in depressions.
DRAINAGE AND PERMEABILITY: Well drained and moderately well drained. Surface runoff is slow to rapid. Permeability is very slow in the clayey part of the solum and moderate or moderately slow in the underlying sandy loam or sandy clay loam material.
USE AND VEGETATION: Most areas are forested with sugar maple, quaking aspen, white spruce, and balsam fir. Some areas are in pasture or hayland.
DISTRIBUTION AND EXTENT: The western Upper Peninsula of Michigan and northeastern Wisconsin. The series is of small extent.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: St. Paul, Minnesota
SERIES ESTABLISHED: Baraga County, Michigan, 1942.
REMARKS: Diagnostic horizons and features recognized in this pedon are: ochric epipedon - the zone from 0 to 4 inches (A horizon); argillic horizon - the zone from 4 to 28 inches (BE and Bt horizons). Location moved from Baraga County to Ontonagon in order to separate the well drained version from the moderately well drained.