LOCATION RIDGETON MN+IAEstablished Series
TAXONOMIC CLASS: Fine-loamy, mixed, superactive, mesic Pachic Hapludolls
TYPICAL PEDON: Ridgeton loam, on a foot slope of about 7 percent, in a cropped field. (Colors are for moist soil unless otherwise indicated.)
Ap--0 to 25 centimeters; black (10YR 2/1) loam, very dark gray (10YR 3/1) dry; weak fine subangular blocky structure; friable; many fine roots; about 2 percent gravel; neutral; abrupt smooth boundary.
A1--25 to 58 centimeters; black (10YR 2/1) loam, dark gray (10YR 4/1) dry; a few peds of very dark brown (10YR 2/2); weak very fine and fine subangular structure; friable; many fine and very fine roots; about 2 percent gravel; neutral; gradual wavy boundary.
A2--58 to 74 centimeters; very dark gray (10YR 3/1) clay loam, dark grayish brown (10YR 4/2) dry; weak medium subangular; blocky structure; friable; many fine and very fine roots; about 3 percent gravel; neutral; gradual wavy boundary. (Combined thickness of the A horizon is 50 to 90 centimeters.)
AB--74 to 97 centimeters; very dark grayish brown (10YR 3/2) loam, dark grayish brown (10YR 4/2) dry; moderate medium subangular blocky structure; friable; common fine and very fine roots; about 3 percent gravel; neutral; gradual smooth boundary. (0 to 40 centimeters thick)
Bw--97 to 127 centimeters; dark brown (10YR 3/3) loam, brown (10YR 5/3) dry; weak medium subangular blocky structure; friable; common fine and very fine roots; about 4 percent gravel; neutral; gradual wavy boundary. (0 to 50 centimeters thick)
C--127 to 203 centimeters; dark yellowish brown (10YR 4/4) loam; massive; friable; few very fine roots; about 5 percent gravel; slightly effervescent; slightly alkaline.
TYPE LOCATION: Major Land Resource Area (MLRA) 103-Central Iowa and Minnesota Till Prairies, Nicollet County, Minnesota subset; located about 200 feet north and 1,550 feet east of the southwest corner of section 36, T. 109 N., R. 28 W.; USGS Judson topographic quadrangle; lat. 44 degrees 11 minutes 46 seconds N. and long. 94 degrees 08 minutes 39 seconds W., NAD 83.
RANGE IN CHARACTERISTICS:
Thickness of the mollic epipedon--60 to more than 150 centimeters
Depth to carbonates--100 to more than 200 centimeters
Thickness of loamy colluvial sediments--100 to more than 200 centimeters
Organic carbon content at a depth of 125 centimeters--less than 0.3 percent
Clay content in the particle-size control section (weighted average)--18 to 30 percent
Sand content in the particle-size control section (weighted average)--25 to 50 percent
Ap or A horizon:
Hue--10YR
Value--2 or 3
Chroma--1 or 2
Texture--loam or clay loam
Clay content--18 to 35 percent
Sand content--30 to 45 percent
Rock fragment content--0 to 5 percent, mixed lithology
Reaction--slightly acid or neutral
This horizon does not contain fine strata or have an irregular decrease in organic carbon
Some pedons have surface horizons with recent erosional sediments
AB horizon (when present):
Hue--10YR
Value--2 or 3
Chroma--2 or 3
Texture--loam or clay loam
Clay content--18 to 35 percent
Sand content--30 to 45 percent
Rock fragment content--0 to 5 percent, mixed lithology
Reaction--slightly acid or neutral
Bw horizon:
Hue--10YR or 2.5Y
Value--3 or 4
Chroma--3 or 4
Texture--loam, clay loam or sandy loam
Clay content--15 to 30 percent
Sand content--25 to 60 percent
Rock fragment content--0 to 5 percent, mixed lithology
Reaction-- slightly acid or neutral
Organic coats are common on ped faces
Some pedons have a Bt horizon with few to common clay films, however the B/A clay ratio is less then 1.2 as required for an argillic horizon
C horizon (when present):
Hue--10YR or 2.5Y
Value--4 to 6
Chroma--3 or 4
Texture--loam, clay loam, or sandy loam
Clay content--15 to 30 percent
Sand content--25 to 60 percent
Rock fragment content--0 to 10 percent, mixed lithology
Reaction--slightly acid to moderately alkaline
Some pedons have till below a depth of 100 centimeters
A firm till substratum phase is recognized on the Coteau Slope in MLRA 103
2BC and 2C horizon (when present below a depth of 150 centimeters, in MLRA 105):
Hue--7.5YR or 10YR
Value--5 to 8
Chroma--1 to 6
Texture--sand, fine sand, loamy fine sand or loamy sand
Clay content--2 to 10 percent
Sand content--80 to 95 percent
Rock fragment content--0 to 10 percent, mixed lithology
Reaction--moderately acid to neutral
COMPETING SERIES: There are no competing series.
GEOGRAPHIC SETTING:
Parent material--loamy local colluvium which may overlay till
Landform--side slopes and base slopes on moraines or non-glaciated uplands and on treads and risers on stream terraces
Slope--6 to 45 percent
Elevation--200 to 400 meters above sea level
Mean annual air temperature--6 to 10 degrees C
Mean annual precipitation--585 to 965 millimeters
Frost-free period--145 to 205 days
GEOGRAPHICALLY ASSOCIATED SOILS: These are the
Clarion,
Delft,
Lester,
Storden and
Terril soils.
Clarion--are on higher landscape positions on uplands and have a mollic epipedon 25 to 50 centimeters thick
Delft--are on lower landscape positions on base slopes and are frequently saturated at the soil surface during the wettest periods of normal years
Lester--are on higher landscape positions on uplands and have an argillic horizon
Storden--are on higher landscape positions on uplands and have carbonates within a depth of 25 centimeters
Terril--are on lower landscape positions on base slopes and have a frequently saturated zone at a depth of 1 meter during the wettest periods of normal years
DRAINAGE AND SATURATED HYDRAULIC CONDUCTIVITY:
Drainage class--well drained--a frequently saturated zone does not occur within a depth of 1.8 meters during the wettest periods in years when precipitation is within one standard deviation of the 30 year mean of annual precipitation
Saturated hydraulic conductivity--1.00 to 10.00 micrometers per second
USE AND VEGETATION:
More steeply sloping areas are non-cropped escarpments, either in woods or permanent pasture. More gently sloping areas are cultivated. The principal corps are corn, soybeans, and small grain. The native vegetation is mixed big bluestem, little bluestem, switchgrass, other grasses of the tall grass prairie and scattered hardwood trees on steep escarpments along river valleys.
DISTRIBUTION AND EXTENT:
Physiographic Division--Interior Plains
Physiographic Province--Central Lowland
Physiographic Section--Western lake section, Wisconsin driftless section, and Dissected till plains
MLRAs--Central Iowa and Minnesota Till Prairies (103),
Eastern Iowa and Minnesota Till Prairies (104), and
Northern Mississippi Valley Loess Hills (105)
LRR M; north-central and northwestern Iowa, and southern Minnesota
Extent--small
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: St. Paul, Minnesota; MLRA SSO 10-5 (Albert Lea, Minnesota)
SERIES ESTABLISHED: Waseca County, Minnesota, 2001.
REMARKS:
Particle-size control section--the zone from a depth of 25 to 100 centimeters;
series control section--the zone from the surface to a depth of 150 centimeters.
Diagnostic horizons and features recognized in this pedon include:
mollic epipedon--the zone from the soil surface to a depth of 97 centimeters (Ap, A1, A2, and AB horizons)
cambic horizon--the zone from a depth of 97 centimeters to 127 centimeters;
udic moisture regime.
The organic carbon content at a depth of 125 centimeters is less than 0.3 percent.
A firm till substratum phase is recognized on the Coteau Slope in MLRA 103.
This series replaces the Terril soils, where correlated on steeper slopes, as the concept of Terril has changed to moderately well drained with saturation in the lower third of the series controls section.
Cation-exchange activity class is inferred from lab data from similar soils in the surrounding area.
Taxonomy version--Keys to Soil Taxonomy, tenth edition, 2006.