LOCATION MARLEAN IA+MNEstablished Series
TAXONOMIC CLASS: Loamy-skeletal, mixed, superactive, mesic Typic Hapludolls
TYPICAL PEDON: Marlean loam, on a south-facing, convex slope of about 4 percent, in a cultivated field. (Colors are for moist soil unless otherwise stated.)
Ap--0 to 15 centimeters (0 to 6 inches); very dark brown (10YR 2/2) loam, very dark grayish brown (10YR 3/2) dry; weak fine granular structure; friable; neutral; abrupt smooth boundary.
A--15 to 23 centimeters (6 to 9 inches); very dark brown (10YR 2/2) loam, dark grayish brown (10YR 4/2) dry; weak very fine subangular blocky structure parting to weak very fine granular; friable; neutral; clear smooth boundary. [Combined thickness of the A horizon is 13 to 30 centimeters (5 to 12 inches).]
Bw--23 to 30 centimeters (9 to 12 inches); mixed very dark grayish brown (10YR 3/2) and brown (10YR 4/3) loam, grayish brown (10YR 5/2) and brown (10YR 5/3) dry; weak very fine subangular blocky structure; friable; neutral; abrupt wavy boundary. [8 to 15 centimeters (3 to 6 inches) thick]
2C--30 to 203 centimeters (12 to 80 inches); mixed very dark grayish brown (10YR 3/2), dark brown (10YR 3/3), and brown (10YR 4/3) very flaggy loam; massive; friable; about 45 percent rock fragments, mostly flagstones with about 15 percent channers; strongly effervescent; slightly alkaline.
TYPE LOCATION: Major Land Resource Area (MLRA) 105-Northern Mississippi Valley Loess Hills; Winneshiek County, Iowa subset; about 4 miles south and 7 miles west of Decorah; about 328 meters (1,075 feet) east and 18 meters (60 feet) north of the southwest corner of section 5, T. 97 N., R. 9 W.; USGS Fort Atkinson quadrangle; lat. 43 degrees 14 minutes 29.9 seconds N. and long. 91 degrees 56 minutes 22.3 seconds W., NAD 83.
RANGE IN CHARACTERISTICS:
Thickness of mollic epipedon--20 to 50 centimeters (8 to 20 inches)
Depth to carbonates--20 to 50 centimeters (8 to 20 inches)
Clay content of the particle size control section (weighted average)--12 to 30 percent
Sand content of the particle size control section (weighted average)--30 to 70 percent
A or Ap horizon:
Hue--10YR
Value: 2 or 3
Chroma--1 or 2
Texture--loam, silt loam, silty clay loam, clay loam, sandy clay loam, sandy loam, or fine sandy loam
Clay content--8 to 30 percent
Sand content--10 to 60 percent
Rock fragment content--0 to 10 percent
Reaction--slightly acid or neutral
Bw horizon:
Hue--7.5YR, 10YR, or 2.5Y
Value--3 to 6
Chroma--2 to 6
Texture--loam, sandy clay loam, or clay loam
Clay content--18 to 30 percent
Sand content--30 to 70 percent
Rock fragment content--0 to 15 percent
Reaction--slightly acid or neutral
2C horizon:
Hue--7.5YR, 10YR, or 2.5Y
Value--3 to 6
Chroma--2 to 6
Texture--very flaggy loam, very flaggy clay loam, very flaggy sandy clay loam, or extremely flaggy analogs
Clay content--12 to 30 percent
Sand content--30 to 70 percent
Rock fragment content--35 to 70 percent, primarily limestone with some sandstone, mostly flagstones with some channers
Reaction--neutral or slightly alkaline
COMPETING SERIES: These are the
Bentonsport,
Kankakee,
Lacrescent, and
May City series.
Bentonsport--have a mollic epipedon 61 to 91 centimeters (24 to 36 inches) thick
Kankakee--are in an area that has a mean annual air temperature range of 10 to 12 degrees C (50 to 54 degrees F) and have a rock fragment content of 20 to 70 percent cobbles within a depth of 51 to 114 centimeters (20 to 45 inches)
Lacrescent--have a mollic epipedon 25 to 50 centimeters (10 to 20 inches) thick, have carbonates within depths of 50 to 75 centimeters (20 to 36 inches), and have a rock fragment content of more than 15 percent in the upper third of the series control section
May City--have carbonates within depths of 0 to 71 centimeters (0 to 28 inches) and have a rock fragment content of more than 15 percent in the upper third of the series control section
GEOGRAPHIC SETTING:
Parent material--20 to 50 centimeters (8 to 20 inches) of loamy glacial or eolian sediments and in the underlying loamy residuum from limestone bedrock
Landform--ridges, interfluves, and side slopes on dissected uplands
Slopes--2 to 80 percent
Elevation--213 to 396 meters (700 to 1,300 feet) above sea level
Mean annual temperature--7 to 9 degrees C (45 to 49 degrees F)
Mean annual precipitation--76 to 86 centimeters (30 to 34 inches)
Frost-free period--145 to 170 days
GEOGRAPHICALLY ASSOCIATED SOILS: These are the
Jacwin,
Nordness,
Rockton, and
Terril soils.
Jacwin--are at slightly higher elevations on structural benches and have residuum from calcareous shale within depths of 76 to 102 centimeters (30 to 40 inches)
Nordness--are at higher elevations on steep side slopes, have lithic contact of limestone within a depth of 20 to 51 centimeters (8 to 20 inches), and do not have a mollic epipedon
Rockton--are at lower elevations on side slopes and have a rock fragment content of less than 15 percent in the particle-size control section
Terril--are at lower elevations on base slopes and have a mollic epipedon 61 to 91 centimeters (24 to 36 inches) thick
DRAINAGE AND PERMEABILITY:
Drainage class--well drained--saturation does not occur within a depth of 1.8 meters (6 feet) during the wettest periods of normal years
Saturated hydraulic conductivity--moderately high in the loamy glacial or eolian sediments and high in the underlying loamy residuum
Surface runoff potential--low to very high, depending on slope
USE AND VEGETATION:
Most gently sloping areas are cultivated. The principal crops are corn, soybeans, small grains, and legume hays. More steeply sloping areas are pastured. The native vegetation is big bluestem, little bluestem, switchgrass, and other grasses of the tall grass prairie.
DISTRIBUTION AND EXTENT:
Physiographic Division--Interior Plains
Physiographic Province--Central Lowland
Physiographic sections--Wisconsin driftless section and Dissected till plains
MLRAs--Northern Mississippi Valley Loess Hills (105) and Eastern Iowa and Minnesota Till Prairies (104)
LRR M; northeastern Iowa and southeastern Minnesota
Extent--moderate
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Indianapolis, Indiana
SERIES ESTABLISHED: Goodhue County, Minnesota, 1972
REMARKS:
Particle-size control section--the zone from a depth of 25 to 100 centimeters (10 to 39 inches) (Bw and 2C horizons);
series control section--the zone from the surface to a depth of 150 centimeters (59 inches) (Ap, A, Bw and 2C horizons).
Diagnostic horizons and features recognized in this pedon:
mollic epipedon--the zone from the surface to a depth of 30 centimeters (0 to 12 inches);
udic moisture regime.
Cation-exchange activity class is inferred from lab data from similar soils in the surrounding area.
Taxonomy version--Keys to Soil Taxonomy, ninth edition, 2003.