LOCATION LERDAL MN+IAEstablished Series
TAXONOMIC CLASS: Fine, smectitic, mesic Aeric Vertic Epiaqualfs
TYPICAL PEDON: Lerdal silty clay loam, with a plane slope of about 4 percent, on a glacial moraine, at an elevation of about 1,290 feet, in a pasture. (Colors are for moist soil unless otherwise stated.)
Ap--0 to 7 inches; black (10YR 2/1) silty clay loam, dark gray (10YR 4/1) dry; weak very fine subangular blocky structure; friable; about 2 percent gravel, mostly shale; slightly acid; abrupt smooth boundary (6 to 10 inches thick)
E--7 to 9 inches; very dark gray (10YR 3/1) silty clay loam, gray (10YR 6/1) dry; many fine faint dark gray (10YR 4/1) Fe depletions; moderate fine subangular blocky structure; friable; about 2 percent gravel, mostly shale; moderately acid; clear wavy boundary. (0 to 6 inches thick)
Bt1--9 to 14 inches; dark grayish brown (10YR 4/2) silty clay loam, few medium prominent light olive brown (2.5Y 5/6) Fe concentrations; moderate fine and medium subangular blocky structure; firm; common faint very dark grayish brown (10YR 3/2) coats and clay films on faces of peds; about 2 percent gravel, mostly shale; moderately acid; clear wavy boundary. (0 to 10 inches thick)
Bt2--14 to 20 inches; olive brown (2.5Y 4/4) silty clay loam; common fine distinct light olive brown (2.5Y 5/6) Fe concentrations; moderate fine and medium subangular blocky structure; very firm; common distinct very dark grayish brown (2.5Y 3/2) coats and clay films on faces of peds; about 2 percent gravel, mostly shale; very strongly acid; clear wavy boundary.
Btg1--20 to 30 inches; grayish brown (2.5Y 5/2) silty clay; common fine distinct light olive brown (2.5Y 5/6) Fe concentrations; moderate medium and coarse prismatic structure; very firm; common distinct very dark grayish brown (10YR 3/2) clay films on faces of peds; about 2 percent gravel, mostly shale; strongly acid; clear wavy boundary.
Btg2--30 to 42 inches; grayish brown (2.5Y 5/2) clay loam; many fine and medium distinct light olive brown (2.5Y 5/4) Fe concentrations; weak coarse prismatic structure; firm; common faint very dark grayish brown (2.5Y 3/2) clay films on faces of peds and in root channels; about 5 percent gravel, mostly shale; slightly acid; abrupt wavy boundary. (Combined thickness of Bt and Btg horizons is 15 to 36 inches.)
Bw--42 to 47 inches; olive brown (2.5Y 4/4) clay loam; many fine and medium faint light olive brown (2.5Y 5/4) Fe concentrations; weak coarse prismatic structure; firm; common prominent clay films in root channels; about 5 percent gravel, mostly shale; slightly effervescent in parts; neutral in parts and slightly alkaline in other parts; clear wavy boundary. (0 to 10 inches thick)
Bk--47 to 60 inches; grayish brown (2.5Y 5/2) clay loam; many fine and medium distinct light olive brown (2.5Y 5/4) Fe concentrations; massive; firm; about 5 percent gravel, mostly shale; few prominent black (10YR 2/1) clay films in root channels; common white soft limy masses; strongly effervescent; slightly alkaline.
TYPE LOCATION: Freeborn County, Minnesota; about 6 miles northeast of Albert Lea; located about 2,600 feet south and 1,800 feet east of the northwest corner of section 13, T. 103 N., R. 21 W.; USGS Albert Lea East topographic quadrangle; lat. 43 degrees 43 minutes 27 seconds N. and long. 93 degrees 18 minutes 12 seconds W., NAD 83.
RANGE IN CHARACTERISTICS: Depth to carbonates ranges from 25 to 65 inches. Gravel, dominated by shale, ranges from 1 to 8 percent by volume, but some pedons do not have rock fragments in the upper part. The sand fraction of these soils is dominated by shale.
The Ap or A horizon has hue of 10YR, value of 2 or 3, and chroma of 1 or 2. The E horizon, where present, has hue of 10YR, value of 3 to 5, and chroma of 1 or 2. Some pedons have redoximorphic features. The A and E horizons are loam, silt loam, clay loam, or silty clay loam. They are slightly or moderately acid.
The Bt horizon has a matrix hue of 10YR or 2.5Y, value of 4 or 5, and chroma of 1 or 2, above depths of 30 inches, but at least some subhorizon has chroma of 3 or 4 in 40 percent or more of the matrix. Below depths of 30 inches, hue is 2.5Y or 5Y, value of 4 or 5, and chroma of 2 to 4. It has few to many and faint to prominent Fe depletions and concentrations. It is clay loam, silty clay loam, silty clay, or clay with a B/A clay ratios of 1.2 to 1.4. It averages between 35 and 45 percent clay and from 10 to 30 percent sand at least in the upper 20 inches. It has subhorizons with as much as 55 percent clay in some pedons. It is moderately to very strongly acid in the upper part and moderately acid to slightly alkaline in the lower part.
The Bw, Bk or C horizon has hue of 2.5Y or 5Y, value of 5 or 6, and chroma of 2 to 4. It is loam, clay loam, silty clay loam, silty clay, or clay. It has few or common masses of lime in the upper part.
COMPETING SERIES: These are the Bevier and Mexico series. Bevier and Mexico soils do not have carbonates in the series control section.
GEOGRAPHIC SETTING: Lerdal soils have plane or convex slopes on gently sloping to moderately steep or hilly glacial moraines. Slope gradients are commonly 2 to 8 percent but range from 1 to 18 percent. Lerdal soils formed in about 3 to 10 feet or more of moderately fine or fine textured clayey glacial till or flow till, high in content of shale over calcareous loam or clay loam till common to the Des Moines lobe of the Late Wisconsinan glacial stage. Mean annual air temperature ranges from 45 to 52 degrees F. Mean annual precipitation ranges from 28 to 32 inches. Frost-free period ranges from 125 to 172 days. Elevation ranges from 800 to 1,500 feet above sea level.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the Kilkenny, Mazaska, and Shields soils which are members of a hydrosequence with Lerdal soils. Moderately well drained Kilkenny soils have more convex slopes or are on higher lying terrain. The somewhat poorly drained Shields soils are on nearly level terrain. Poorly drained Mazaska soils are in nearby shallow depressions, swales, and low lying level areas.
DRAINAGE AND PERMEABILITY: Somewhat poorly drained. Surface runoff is high to very high. Permeability is slow. The perched seasonal high water table is 1.5 to 2.5 feet during April to May in normal years.
USE AND VEGETATION: Most are cultivated. The principal crops are corn, soybeans, and alfalfa. Native vegetation is savanna with oaks being the dominant kind of tree.
DISTRIBUTION AND EXTENT: Eastern edge of Des Moines lobe in Minnesota. Moderately extensive.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: St. Paul, Minnesota
SERIES ESTABLISHED: Hennepin County, Minnesota, 1969.
REMARKS: Diagnostic horizons and features in this pedon include: ochric epipedon - from the soil surface to a depth of 7 inches - too thin for a mollic horizon (Ap); albic horizon - the zone from 7 to 9 inches (E); argillic horizon - the zone from 8 to 42 inches (Bt1, Bt2, Btg1, Btg2).
This pedon has been reclassified to Fine, smectitic mesic Aeric Vertic Epiaqualf on 12/96