LOCATION FORBAY MNEstablished Series
TAXONOMIC CLASS: Fine-loamy, mixed, superactive, frigid Mollic Hapludalfs
TYPICAL PEDON: Forbay loam on a convex backslope of 18 percent, on a ground moraine in a hay field at an elevation of about 369 meters. (Colors are for moist soil unless otherwise stated.)
Ap--0 to 18 cm; very dark grayish brown (10YR 3/2) loam, grayish brown (10YR 5/2) dry; moderate medium granular structure; very friable; many fine and very fine roots; 5 percent gravel and 1 percent cobbles; strongly acid; abrupt smooth boundary. (15 to 20 cm thick)
E/B--18 to 38 cm; 90 percent dark reddish gray (5YR 4/2) silt loam (E), and 10 percent reddish brown (5YR 4/4) loam (Bt); moderate medium subangular blocky structure; very friable; many fine and very fine roots; 8 percent gravel; very strongly acid; clear wavy boundary. (0 to 15 cm thick)
2Bt1--38 to 89 cm; reddish brown (5YR 4/4) loam, moderate medium subangular blocky structure; friable; many fine and very fine roots; few patchy faint reddish brown (5YR 4/4) clay films on ped faces; few fine distinct strong brown (7.5YR 5/6) Fe concentrations; 8 percent gravel; strongly acid; gradual smooth boundary.
2Bt2--89 to 140 cm; reddish brown (5YR 4/3) loam; moderate medium subangular blocky structure; friable; common fine and very fine roots; few patchy faint reddish brown (5YR 4/4) clay films on ped faces; 8 percent gravel; strongly acid; gradual wavy boundary. (Combined thickness of the 2Bt horizon is 51 to 114 centimeters.)
2BC--140 to 191 cm; reddish brown (5YR 4/4) loam; weak coarse subangular blocky structure; friable; 8 percent gravel; moderately acid; clear smooth boundary. (25 to 76 cm thick)
3BCd--191 to 203 cm; reddish brown (5YR 4/4) gravelly sandy loam; moderate very coarse and extremely coarse prismatic structure parting to moderate fine and medium platy, few 2 to 3 millimeter oblique fractures 0.5 to 3.0 feet apart very firm; 18 percent gravel; moderately acid.
TYPE LOCATION: St. Louis County, Minnesota; about 4 miles east of the town of Esko; 1,700 feet south and 2,100 feet west of the northeast corner of section 18, T.49 N., R.15 W.; USGS Esko, Minnesota Quadrangle; latitude 46 degrees 43 minutes 50 seconds N. and longitude 92 degrees 17 minutes 20 seconds W., NAD 27.
RANGE IN CHARACTERISTICS: Thickness of the mantle and depth to fine loamy till ranges from 0 to 41 cm. The depth to dense till ranges from 152 to 203 cm. The depth to free carbonates is greater than 203 cm. Volume of rock fragments throughout the upper mantle and fine loamy till ranges from 1 to 12 percent with 1 to 10 percent gravel, 0 to 1 percent cobbles and 0 to 1 percent stones and boulders. Rock fragment content in the dense till ranges from 8 to 25 percent with 8 to 25 percent gravel, 0 to 10 percent cobbles and 0 to 5 percent stones and boulders. The mantle averages less than 18 percent clay. The argillic horizon ranges from 18 to 25 percent clay. The fine loamy till ranges from 16 to 22 percent clay and contains less than 45 percent sand. The dense till ranges from 3 to 10 percent clay and contains less than 72 percent sand.
The Ap or A horizon has hue of 10YR, value and chroma of 2 or 3. Dry color has a hue of 17.5YR or 10YR, value of 5 or 6 and chroma of 2 or 3. It is loam, silt loam, or fine sandy loam. Reaction is very strongly acid to moderately acid.
The E/B horizon, when present, does not meet the criteria for a glossic horizon. The E part has a hue of 5YR or 7.5YR value of 4 or 5 and chroma of 2 or 3. The Bt part has hue of 7.5YR or 5YR, value of 4 or 5 and chroma of 4. It is silt loam, very fine sandy loam, sandy loam, fine sandy loam, or loam. Reaction is strongly acid to slightly acid.
Some pedons have a Bw horizon, with a hue of 5 YR to 7.5YR, value of 4 or 5 and chroma of 3 or 4. It is silt loam, very fine sandy loam, fine sandy loam, or loam. Reaction is very strongly to moderately acid.
The 2Bt horizon has a hue of 5YR or 7.5YR, value of 4 or 5, and chroma of 3 or 4. It is loam, clay loam or silt loam. Reaction is strongly acid to slightly acid.
The 2BC horizon has a hue of 5YR, value of 3, 4, or 5, and chroma of 3 or 4. It is loam or silt loam. Reaction is moderately acid to neutral.
The 3BCd horizon has a hue of 2.5YR or 5YR with value and chroma of 3 or 4. It is sandy loam or fine sandy loam or their gravelly analogues. Rock fragment content ranges from 8 to 25 percent with 8 to 25 percent gravel, 0 to 10 percent cobbles and 0 to 5 percent stones and boulders. It is firm or very firm. It is moderately acid to neutral.
COMPETING SERIES: This is the Waukon series. Waukon soils have a clay content ranging from 18 to 35 percent and depth to carbonates are from 46 to 122 centimeters.
GEOGRAPHIC SETTING: These soils have mainly complex slopes with gradients of 8 to 45 percent. They are on shoulders and backslopes of moraines. This soil formed in a discontinuous mantle of eolian or water laid sediments and the underlying friable till and the underlying dense loamy till. The till is from the Superior Lobe of the Late Wisconsinan glaciation. Mean annual air temperature ranges from 4 to 7 degrees C. Mean annual precipitation ranges from 625 to 750 mm. The frost free season ranges from 120 to 140 days. The elevation ranges from 300 to 500 meters above sea level.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the Augustana, Eldes, Hegberg and Wahbegon soils. The moderately well drained Augustana soil occurs on backslopes and summits. The poorly drained Eldes and very poorly drained Wahbegon both occur on plane or concave positions in addition the Eldes soil can occur on toeslopes. The somewhat poorly drained Hegberg soil occurs on footslopes and summits.
DRAINAGE AND SATURATED HYDRAULIC CONDUCTIVITY: Well drained. Surface runoff is low to high. Saturated hydraulic conductivity is 4.23 to 42.34 micrometers per second (0.60 to 6 inches per hour) in the upper mantle, 1.41 to 14.11 micrometers per second (0.20 to 2.0 inches per hour) in the middle part and .01 to .042 micrometers per second (0.0015 to 0.006 inches per hour) in the lower part.
USE AND VEGETATION: These soils are used for timber and crop production. Common trees are quaking aspen, paper birch, American basswood, sugar maple, northern red oak, eastern white pine, balsam fir and white spruce. Hay, pasture and small grains are the most common crops.
DISTRIBUTION AND EXTENT: MLRA-90A. Northeastern Minnesota. Moderately Extensive.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: St. Paul, Minnesota.
SERIES ESTABLISHED: St. Louis County, Minnesota (Duluth subset), 2007.
REMARKS: Diagnostic horizons and features recognized in this pedon include: ochric epipedon - the zone from the surface to a depth of 38 cm (Ap and E/B horizon); argillic horizon - the zone from a depth of 38 to 140 cm (Bt1 and Bt2 horizons); Densic contact - 191 cm (3BCd horizon)
The designation of the 3BCd horizon is based on fractures and platy structure in the densic material. Clay and silt translocation can be seen between the horizontal plates when broken apart.