LOCATION ROCKTON MN+IA IL IN WIEstablished Series
TAXONOMIC CLASS: Fine-loamy, mixed, superactive, mesic Typic Argiudolls
TYPICAL PEDON: Rockton loam, on a convex slope of 2 percent, on bedrock-controlled, glaciated upland, in a cultivated field. (All colors are for moist soil unless otherwise stated.)
Ap--0 to 25 centimeters; very dark brown (10YR 2/2) loam, very dark grayish brown (10YR 3/2) dry; weak very fine granular structure; very friable; slightly acid; abrupt wavy boundary. (15 to 25 centimeters thick)
AB--25 to 38 centimeters; very dark grayish brown (10YR 3/2) loam, dark grayish brown (10YR 4/2) dry; weak fine subangular blocky structure; very friable; very dark brown (10YR 2/2) coats on faces of peds; moderately acid; clear irregular boundary. (0 to 20 centimeters thick)
Bt1--38 to 53 centimeters; brown (10YR 4/3) loam; moderate fine angular blocky structure; friable; very dark grayish brown (10YR 3/2) coats on faces of peds; few fine pores; few thin clay films on faces of peds; about 3 percent coarse fragments; strongly acid; clear wavy boundary
Bt2--53 to 66 centimeters; dark yellowish brown (10YR 4/4) sandy clay loam; moderate fine subangular blocky structure; friable; brown (10YR 4/3) coats on faces of peds; few variable sized pores; many thin clay films on faces of peds and clay bridges between sand grains; about 3 percent rock fragments; strongly acid; clear wavy boundary. (Combined thickness of the Bt horizon is 10 to 50 centimeters.)
2Bt3--66 to 79 centimeters; dark yellowish brown (10YR 4/4) light clay; moderate fine subangular blocky structure; firm; many thin and medium clay films on faces of peds; about 3 percent rock fragments; moderately acid; clear wavy boundary. (0 to 15 centimeters thick)
2R--79 centimeters; limestone bedrock, weathered along joints and partially fractured in the upper 60 centimeters.
TYPE LOCATION: Major Land Resource Area (MLRA) 105-Northern Mississippi Valley Loess Hills, Olmsted County, Minnesota subset; about 9 miles east and 5 miles south of Rochester; located about 1,295 feet west and 170 feet south of the northeast corner of section 31, T. 106 N., R. 12 W.; USGS Marion topographic quadrangle; lat. 43 degrees 56 minutes 54 seconds N. and long. 92 degrees 18 minutes 14 seconds W., NAD 83.
RANGE IN CHARACTERISTICS:
Mollic epipedon thickness--25 to 49 centimeters
Depth to carbonates--50 to 100 centimeters
Depth to bedrock--50 to 100 centimeters
Clay content in the particle-size control section (weighted average)--24 to 35 percent
Sand content in the particle-size control section (weighted average)--25 to 55 percent
Ap or A horizon:
Hue--10YR
Value--2 or 3
Chroma--1 or 2
Texture--loam, fine sandy loam or silt loam
Clay content--15 to 27 percent
Sand content--20 to 60 percent
Rock fragment content--0 to 10 percent, mixed lithology
Reaction--strongly acid to neutral
AB horizon (when present):
Hue--10YR
Value--2 to 4
Chroma--1 to 3
Texture--loam, fine sandy loam or silt loam
Clay content--15 to 27 percent
Sand content--20 to 60 percent
Rock fragment content--0 to 10 percent, mixed lithology
Reaction--strongly acid to neutral
Bt horizon:
Hue--5YR, 7.5YR, or 10YR
Value--4 or 5
Chroma--3 or 4
Texture--loam, clay loam, sandy clay loam, sandy loam or silt loam
Clay content--15 to 35 percent
Sand content--20 to 60 percent
B/A clay ratio--1.2 to 1.4
Rock fragment content--0 to 10 percent, mixed lithology
Reaction--strongly acid to slightly acid
Some pedons on strath terraces have sandy loam in the lower part of the Bt horizon
2Bt horizon (when present):
Hue--5YR, 7.5YR or 10YR
Value--3 to 6
Chroma--3 to 8
Texture--clay loam, silty clay loam, clay or silty clay
Clay content--35 to 75 percent
Sand content--15 to 35 percent
Rock fragment content--0 to 10 percent, mixed lithology
Reaction--moderately acid to neutral
Some pedons, on strath terraces, have a 3C horizon that is very to extremely channery fine sandy loam, sandy loam, loam, or sandy clay loam
COMPETING SERIES: These are the
Atkinson,
Burchard,
Cokato,
Cresco,
Cresent,
Durand,
Friesland,
Griswold,
Hitt,
Jasper,
Joslin,
Keosauqua,
Kishwaukee,
Marbletown,
Moingona,
Morrill,
Nuxmaruhanixete,
Pana,
Parmod,
Penfield,
Reedslake,
Ringwood,
Schoolcraft,
Shelby,
Sibleyville,
Velma, and
Winnebago series.
Atkinson--do not have limestone bedrock within a depth of 100 centimeters
Burchard--have a clay content of 25 to 35 percent and a sand content of 30 to 45 percent in the lower third of the series control section
Cokato--have a clay content of 18 to 27 percent and a sand content of 35 to 45 percent in the lower third of the series control section
Cresco--have a clay content of 28 to 35 percent in the lower third of the series control section
Cresent--have a clay content of 2 to 10 percent and a sand content of 70 to 95 percent in the lower third of the series control section
Durand--have matrix hues of 5YR or 7.5YR in the middle third of the series control section and have less than 27 percent clay and more than 40 percent sand in the lower third of the series control section
Friesland--have less than 27 percent clay, less than 40 percent sand, and do not have rock fragments in the lower third of the series control section
Griswold--a rock fragment content of 10 to 35 percent, and calcium carbonate equivalent ranging from 10 to 40 percent in the lower third of the series control section
Hitt--have limestone bedrock within a depth of 150 centimeters and have matrix hues of 2.5YR, 5YR, or 7.5YR in the middle third of the series control section
Jasper--have a clay content of 5 to 20 percent, an average sand content of 45 to 70 percent, and less than 10 percent gravel in the lower third of the series control section
Joslin--have a matrix hue of 2.5YR and a clay content averaging between 35 and 50 percent in the middle third of the series control section
Keosauqua--have a clay content of 2 to 10 percent, a sand content of 80 to 90 percent, and a rock fragment content of 1 to 10 percent in the lower third of the series control section
Kishwaukee--have a clay content of 18 to 30 percent and a rock fragment content of 15 to 35 percent in the lower third of the series control section
Marbletown--have a paralithic contact in sandstone or shale within a depth of 150 centimeters
Moingona--have a clay content of 15 to 30 percent in the lower third of the series control section
Morrill--have matrix hues of 5YR or 7.5YR in the middle third of the series control section and have a clay content of 5 to 30 percent in the lower third of the series control section
Nuxmaruhanixete--have a clay content of 2 to 5 percent and a rock fragment content of 15 to 60 percent in the lower third of the series control section
Pana--have a matrix hue of 5YR or 7.5YR and a rock fragment content of 15 to 35 percent in the lower third of the series control section
Parmod--have calcium carbonate equivalent range of 15 to 40 percent and a rock fragment content of 3 to 15 percent in the lower third of the series control section
Penfield--have a clay content of 12 to 32 percent, a sand content of 45 to 65 percent and a rock fragment content of less than 15 percent in the lower third of the series control section
Reedslake--have a zone in the lower third of the series control section that is saturated for at least 30 consecutive days during April to July in normal years
Ringwood--have less than 20 percent clay and a rock fragment content of 10 and 40 percent in the lower third of the series control section
Schoolcraft--have more than 80 percent sand and a rock fragment content of 0 to 25 percent in the lower third of the series control section
Shelby--have a clay content of 25 to 36 percent in the lower third of the series control section
Sibleyville--have sandstone or sandy and silty shale within a depth of 100 centimeters
Velma--have a reaction range of very strongly acid or strongly acid in the middle part of the series control section and have a clay content of 25 to 35 percent in the lower third of the series control section
Winnebago--have matrix hue of 5YR or 7.5YR in the middle part of the series control section and have less than 20 percent clay in the lower third of the series control section
GEOGRAPHIC SETTING:
Parent material--50 to 100 centimeters of loamy sediments with or without a thin paleosol over limestone bedrock
Landform--plane and convex slopes on summits and shoulder slopes on uplands, high structural benches, strath terraces, and lake plains
Slope--0 to 25 percent
Elevation--135 to 470 meters above sea level
Mean annual air temperature--4 to 12 degrees C
Mean annual precipitation--585 to 1,015 millimeters
Frost-free period--135 to 210 days
GEOGRAPHICALLY ASSOCIATED SOILS: These are the
Atkinson,
Channahon,
Dickinson, and
Ostrander soils.
Atkinson--are at higher landscape positions and do not have limestone bedrock within a depth of 100 centimeters
Channahon--are at landscape positions similar to those of the Rockton soils and have a lithic contact within a depth of 50 centimeters
Dickinson--are at lower landscape positions, do not have a lithic contact within a depth of 150 centimeters and have a clay content that averages 10 to 18 percent in the particle-size control section
Ostrander--are at higher landscape positions on interfluves, do not have a lithic contact within a depth of 150 centimeters and have a clay content of 18 to 27 percent in the lower third of the series control section
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 of normal years
Saturated hydraulic conductivity--1.00 to 10.00 micrometers per second in the loamy sediments, 0.01 to 1.00 micrometers per second in the paleosol (when present) and 0.01 to 10.00 micrometers per second in the limestone bedrock depending on the amount of weathered rock
Surface runoff potential--low to high
USE AND VEGETATION:
Most areas are cultivated. The principal crops are corn, soybeans, small grains, and legume hay. 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--Eastern lake section, Western lake section, Dissected till plains, Wisconsin driftless section, Till plains
MLRAs--Wisconsin and Minnesota Thin Loess and Till, Southern Part (90B),
Central Minnesota Sandy Outwash (91),
Southern Wisconsin and Northern Illinois Drift Plain (95B),
Southern Michigan and Northern Indiana Drift Plain (98),
Central Iowa and Minnesota Till Prairies (103),
Eastern Iowa and Minnesota Till Prairies (104),
Northern Mississippi Valley Loess Hills (105),
Illinois and Iowa Deep Loess and Drift (108), and
Northern Illinois and Indiana Heavy till Plain (110),
LRRs K, L, and M; northeastern Iowa, northern Illinois, Indiana, southwestern Wisconsin, and southeastern Minnesota
Extent--moderate
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: St. Paul, Minnesota
SERIES ESTABLISHED: Stephenson County, Illinois, in 1939.
REMARKS:
Particle-size control section--the zone from a depth of 38 to 79 centimeters;
series control section--the zone from the surface to a depth of 79 centimeters.
Diagnostic horizons and features recognized in this pedon include:
mollic epipedon--the zone from the surface to a depth of 38 centimeters (Ap and AB horizons);
argillic horizon--the zone from a depth of 38 to 79 centimeters (Bt1, Bt2, and 2Bt3 horizons);
lithic contact--the contact with limestone bedrock at 79 centimeters;
udic moisture regime.
The upper 0.3 to 1.5 meters of limestone may be significantly fractured and may not be a root restrictive layer.
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.
ADDITIONAL DATA:: Refer to MAES Central File Code No. 869 for results of some laboratory analysis of the typical pedon.