LOCATION HEGBERG MNEstablished Series
TAXONOMIC CLASS: Fine-loamy, mixed, superactive, frigid Aquollic Hapludalfs
TYPICAL PEDON: Hegberg loam, on a slight concave of 2 percent, on a ground moraine in a forest that was once farmed at an elevation of 378 meters. (Colors are for moist soil unless otherwise stated.)
Ap--0 to 15 cm; very dark gray (10YR 3/1) loam, gray (10YR 5/1) dry; moderate fine granular structure; very friable; many fine and very fine roots throughout; 2 percent cobbles and 8 percent gravel; very strongly acid; abrupt smooth boundary. (15 to 20 cm thick)
Bw1--15 to 28 cm; brown (7.5YR 4/3) loam; moderate fine subangular blocky structure; very friable; common fine and very fine roots throughout; 2 percent cobbles and 8 percent gravel; very strongly acid; clear smooth boundary.
Bw2--28 to 41 cm; brown (7.5YR 4/4) fine sandy loam; moderate medium subangular blocky structure; very friable; common fine distinct strong brown (7.5YR 5/6) and few fine faint brown (7.5YR 4/3) Fe depletions; 1 percent cobbles and 8 percent gravel; strongly acid; clear smooth boundary. (Combined thickness of the Bw horizons ranges is 0 to 25 cm.)
2Bt1--41 to 71 cm; reddish brown (5YR 4/4) loam; moderate medium subangular blocky structure; friable; few distinct brown (7.5YR 4/2) Fe depletions; few discontinuous faint reddish brown (5YR 4/3) clay films on faces of peds; 1 percent cobbles and 8 percent gravels; strongly acid; gradual wavy boundary.
2Bt2--71 to 114 cm; reddish brown (5YR 4/4) loam; moderate medium subangular blocky structure; friable; few medium distinct yellowish red (5YR 5/6) and medium distinct reddish brown (5YR 5/4) Fe concentrations; few, discontinuous faint reddish brown (5YR 4/3) clay films on faces of peds; 1 percent cobbles and 8 percent gravel; moderately acid; gradual wavy boundary. (Combined thickness of the 2Bt horizons is 51 to 127 cm.)
2BC--114 to 165 cm; reddish brown (5YR 4/4) loam; moderate medium subangular blocky structure; friable; 1 percent cobbles and 8 percent gravel; moderately acid; clear wavy boundary. (0 to 76 cm thick)
3BCd1--165 to 178 cm; reddish brown (5YR 4/3) loam; moderate very coarse and extremely coarse prismatic structure parting to moderate fine and medium platy, few 2 to 3 millimeter oblique fractures 15 cm to 1 meter apart; very firm; 1 percent cobbles and 8 percent gravel; moderately acid; gradual wavy boundary.
3BCd2--178 to 203 cm, reddish brown (5YR 4/3) sandy loam; moderate very coarse and extremely coarse prismatic structure parting to moderate fine and medium platy, few 2 to 3 millimeter oblique fractures 15 cm to 1 meter apart; very firm; 1 percent cobbles and 8 percent gravel; moderately acid.
TYPE LOCATION: St. Louis County, Minnesota; about 6.5 miles north by northeast of the northeastern city boundary of Duluth; 1,200 feet west and 1,800 feet north of the southeast corner of section 19, T. 52 N., R. 12 W.; USGS French River Minnesota Quadrangle; lat. 46 degrees 58 minutes 21 seconds N. and long. 91 degrees 54 minutes 17 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. 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 value is 5 or less. It is loam, fine sandy loam, or silt loam. Reaction is very strongly to moderately acid.
Some pedons have an E/B or B/E horizon that 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 5YR or 7.5YR, value of 4 or 5, and chroma of 4. It is very fine sandy loam, silt loam, fine sandy loam, or loam. Reaction is very strongly acid to strongly acid.
The Bw horizon has a hue of 5YR or 7.5YR, value of 4 or 5, and chroma of 3 or 4. It is loam, fine sandy loam, very fine sandy loam or silt loam. The Bw horizon typically has faint to distinct Fe concentrations and depletions. Reaction is very strongly acid to moderately acid.
The 2Bt horizon has a hue of 5YR or 7.5YR, value of 4, and chroma of 3 or 4. It is loam, clay loam or silt loam. This horizon has redoximorphic features in most pedons. Reaction is strongly acid to moderately acid.
The 2BC horizon has a hue of 5YR or 7.5YR, value of 4, and chroma of 3 or 4. It is loam or silt loam. Reaction is moderately acid to slightly acid.
The 3BCd horizon has a hue of 5YR or 2.5YR and value and chroma of 3 or 4. It is sandy loam, 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: There are no competing series.
GEOGRAPHIC SETTING: These soils typically occur on simple slopes of 0 to 3 percent. They are on foot slopes and summits of moraines. This soil formed in a discontinuous mantle of eolian or water laid sediments and the underlying friable loamy 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, Forbay, and Wahbegon soils. The moderately well drained Augustana soils occur 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 well drained Forbay soils occur on shoulder and backslopes.
DRAINAGE AND SATURATED HYDRAULIC CONDUCTIVITY: Somewhat poorly drained. Surface runoff is negligible to low. 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. The Hegberg soils have perched seasonal high saturation as high as 33 cm from the surface during spring in normal years.
USE AND VEGETATION: Most areas are used for agricultural cropland. Hay, pasture and small grains are the most common crops. Some areas are forested with common trees of quaking aspen, paper birch, American basswood, sugar maple, northern red oak, eastern white pine, balsam fir and white spruce.
DISTRIBUTION AND EXTENT: MLRA-90. Northeastern Minnesota. Moderately extensive.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: St. Paul, Minnesota
SERIES ESTABLISHED: St. Louis County (Duluth subset), Minnesota, 2007.
REMARKS: Diagnostic horizons and features in this pedon include: ochric epipedon - the zone from the mineral soil surface to 15 cm (Ap horizon); cambic horizon - the zone from 15 to 43 cm (Bw horizons); argillic horizon - the zone from 43 to 114 cm (2Bt1 and 2Bt2 horizons); densic contact - the zone starting at 165 cm(3BCd1)
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.