LOCATION KENNEBEC IA+KS MN MO NE SDEstablished Series
TAXONOMIC CLASS: Fine-silty, mixed, superactive, mesic Cumulic Hapludolls
TYPICAL PEDON: Kennebec silt loam, on a slope of about 1 percent, in a cultivated field. (Colors are for moist soil unless otherwise stated.)
Ap--0 to 20 centimeters; black (10YR 2/1) silt loam, very dark gray (10YR 3/1) dry; moderate fine granular structure; friable; common fine and very fine roots; few fine and very fine pores; slightly acid; clear smooth boundary.
A1--20 to 46 centimeters; black (10YR 2/1) silt loam, very dark gray (10YR 3/1) dry; moderate fine subangular blocky structure; friable; common fine and very fine roots; common fine pores; slightly acid; diffuse smooth boundary.
A2--46 to 81 centimeters; black (10YR 2/1) silt loam, very dark gray (10YR 3/1) dry, very dark brown (10YR 2/2) crushed; moderate fine and medium subangular blocky structure; friable; common fine and very fine roots; common fine and medium pores; slightly acid; diffuse smooth boundary.
A3--81 to 104 centimeters; black (10YR 2/1) silt loam, dark gray (10YR 4/1) dry, very dark brown (10YR 2/2) crushed; weak fine and medium subangular blocky structure; friable; few very fine roots; few fine and medium pores; many large worm holes; slightly acid; diffuse smooth boundary. (Combined thickness of the A horizon is 75 to 127 centimeters.)
AC--104 to 137 centimeters; very dark gray (10YR 3/1) silt loam, very dark grayish brown (10YR 3/2) crushed; weak medium subangular blocky structure; friable; few very fine roots; few very fine pores; slightly acid; diffuse smooth boundary. (0 to 40 centimeters thick)
C1--137 to 160 centimeters; very dark grayish brown (10YR 3/2) silt loam; massive; friable; few fine pores; few fine rounded very dark brown (7.5YR 2.5/2) iron and manganese concretions; common medium faint dark brown (10YR 3/3) and common fine distinct dark yellowish brown (10YR 4/4) redoximorphic concentrations; few fine faint grayish brown (10YR 5/2) redoximorphic depletions; slightly acid; diffuse smooth boundary.
C2--160 to 183 centimeters; very dark grayish brown (10YR 3/2) silt loam; massive; friable; few fine pores; common fine prominent dark yellowish brown (10YR 4/6) redoximorphic concentrations; slightly acid; diffuse smooth boundary.
C3--183 to 203 centimeters; very dark grayish brown (10YR 3/2) silt loam; massive; friable; few fine pores; common fine prominent yellowish brown (10YR 5/6) redoximorphic concentrations; slightly acid.
TYPE LOCATION: Major Land Resource Area (MLRA) 107B-Iowa and Missouri Deep Loess Hills, Crawford County, Iowa subset; about 7 miles southwest of Dow City; located about 2,110 feet north and 62 feet east of the southwest corner of section 27, T. 82 N., R. 41 W.; USGS Dunlap NE topographic quadrangle; lat. 41 degrees 52 minutes 59.5 seconds N. and long. 95 degrees 36 minutes 54.3 seconds W., NAD 83.
RANGE IN CHARACTERISTICS:
Thickness of the mollic epipedon--more than 100 centimeters
Depth to carbonates--more than 200 centimeters
Clay content in the particle-size control section (weighted average)--18 to 30 percent
Sand content in the particle-size control section (weighted average)--less than 10 percent fine sand and sand coarser than fine sand
Ap or A horizon:
Hue--10YR
Value--2 or 3
Chroma--1 or 2
Texture--silt loam or silty clay loam
Clay content--18 to 30 percent
Sand content--less than 10 percent
Reaction--moderately acid to neutral
Overwash phases:
Hue--10YR
Value--3 or 4
Chroma--1 or 2
Texture--silt loam
Clay content--18 to 27 percent
Sand content--less than 10 percent
Reaction--moderately acid to neutral
Thickness--20 to 50 centimeters
AB horizon (if it occurs):
Hue--10YR
Value--2 or 3
Chroma--1 or 2
Texture--silt loam or silty clay loam
Clay content--18 to 32 percent
Sand content--less than 10 percent
Reaction--slightly acid or neutral
AC horizon (if it occurs):
Hue--10YR
Value--2 or 3
Chroma--1 or 2
Texture--silt loam or silty clay loam
Clay content--18 to 32 percent
Sand content--less than 10 percent
Reaction--slightly acid or neutral
Bw horizon (if it occurs):
Hue--10YR or 2.5Y
Value--2 to 4
Chroma--2 or 3
Texture--silt loam or silty clay loam
Clay content--24 to 33 percent
Sand content--less than 15 percent
Reaction--slightly acid or neutral
Some pedons have iron and manganese concretions, redoximorphic concentrations, and redoximorphic depletions
C horizon:
Hue--10YR or 2.5Y
Value--2 to 4
Chroma--1 or 2
Texture--silt loam or silty clay loam
Clay content--24 to 30 percent
Sand content--less than 15 percent
Reaction--slightly acid or neutral
Some pedons have iron and manganese concretions, redoximorphic concentrations, and redoximorphic depletions
COMPETING SERIES: These are the Allison, Anthon, Huntsville, Ivan,
Judson,
Kahola, Kenridge,
Lindstrom, Napier,
Rossville,
Sturkie, and
Worthen series.
Allison--have strata of silt loam, loam, clay loam, or sandy loam and have matrix chroma of 2 to 4 below a depth of 75 centimeters
Anthon--have a sand content of 35 to 95 percent in the lower third of the series control section
Huntsville--have layers immediately below the mollic epipedon with matrix chroma of 3 or 4
Ivan--have carbonates within a depth of 25 centimeters
Judson--have a clay content that averages 30 to 35 percent in the particle-size control section
Kenridge--have a clay content that averages 30 to 35 percent in the particle-size control section
Kahola--have carbonates within a depth of 100 centimeters
Lindstrom--have matrix chroma of 3 or 4 in the cambic horizon
Napier--have a mollic epipedon 61 to 102 centimeters thick and the layers immediately below the mollic epipedon have matrix chroma of 3 or 4
Rossville--are in areas where mean annual precipitation ranges from 870 to 1,020 millimeters
Sturkie--are in areas where mean annual air temperature ranges from 12 to 14 degrees C
Worthen--have a mollic epipedon 61 to 91 centimeters thick and have matrix chroma of 3 to 6 in the lower third of the series control section
GEOGRAPHIC SETTING:
Parent material--alluvium
Landform--flood plains and upland drainageways
Slope--0 to 5 percent
Elevation--180 to 400 meters above sea level
Mean annual air temperature--7 to 12 degrees C
Mean annual precipitation--650 to 870 millimeters
Frost-free period--145 to 180 days
GEOGRAPHICALLY ASSOCIATED SOILS: These are the Colo, Monona, Napier, and
Nodaway soils.
Colo--are in the slightly lower landscape positions on flood plains and are frequently saturated at the soil surface during the wettest periods of normal years
Monona--are at higher landscape positions on uplands and have a mollic epipedon 25 to 61 centimeters thick
Napier--are at higher landscape positions on foot slopes and have a mollic epipedon 61 to 102 centimeters thick
Nodaway--are in landform positions similar to those of the Kennebec soils, are closer to stream channels, and have an ochric epipedon 15 to 25 centimeters thick
DRAINAGE AND SATURATED HYDRAULIC CONDUCTIVITY:
Drainage class--moderately well drained--a frequently saturated zone occurs at depth 0.75 meter during April to June in normal years and is considered apparent
Saturated hydraulic conductivity--1.00 to 10.00 micrometers per second (moderately high)
Surface runoff potential--negligible to low
Flooding--rarely to frequently flooded for brief or very brief periods during the months of February to November
USE AND VEGETATION:
Most areas are cultivated. The principal crops are corn, soybeans, small grain, alfalfa, or clover. The native vegetation is big bluestem, little bluestem, indiangrass, switchgrass, and other grasses of the tall grass prairie.
DISTRIBUTION AND EXTENT:
Physiographic Division--Interior Plains
Physiographic Provinces--Central Lowland, Great Plains
Physiographic sections--Western lake section, Wisconsin driftless section, Till plains, Dissected till plains, and Plains Border
MLRAs--Wisconsin and Minnesota Sandy Outwash (91),
Till Plains (102B),
Central Iowa and Minnesota Till Prairies (103),
Eastern Iowa and Minnesota Till Prairies (104),
Northern Mississippi Valley Loess Hills (105),
Nebraska and Kansas Loess-Drift Hills (106),
Iowa and Missouri Deep Loess Hills (107),
Illinois and Iowa Deep Loess and Drift (108),
Iowa and Missouri Heavy Till Plain (109),
Central Mississippi Valley Wooded Slopes (115), and
Bluestem Hills (76)
LRR M, LRR K and LRR H; Iowa, Minnesota, Nebraska, Missouri, Kansas, and South Dakota
Extent--large
MLRA OFFICE RESPONSIBLE: St. Paul, Minnesota
SERIES ESTABLISHED: Monona County, Iowa, 1956.
REMARKS:
Particle-size control section--the zone from a depth of 25 to 100 centimeters (A1, A2, and A3horizons);
series control section--the zone from the surface to a depth of 150 centimeters (Ap, A1, A2, A3, AC, and C1 horizons).
Diagnostic horizons and features recognized in this pedon include:
mollic epipedon--the zone from the surface to a depth of 137 centimeters (Ap, A1, A2, A3, and AC horizons);
udic moisture regime.
Cation-exchange class is supported by laboratory data from National Soil Survey Laboratory, Lincoln, Nebraska.
Taxonomy version--Keys to Soil Taxonomy, tenth edition, 2006.
These soils do meet the saturation requirements of Aquolls.
ADDITIONAL DATA:
Laboratory data--National Soil Survey Laboratory, Lincoln, Nebraska-user pedon id numbers 95IA047004, 98IA047006L, and 73NE109003, (http://ssldata.sc.egov.usda.gov/).