LOCATION ANKENY IA+MNEstablished Series
TAXONOMIC CLASS: Coarse-loamy, mixed, superactive, mesic Cumulic Hapludolls
TYPICAL PEDON: Ankeny fine sandy loam, on an alluvial fan or toe slope of 2 percent, in a cultivated field. (Colors are for moist soil unless otherwise stated.)
Ap--0 to 18 centimeters; very dark brown (10YR 2/2) fine sandy loam, dark grayish brown (10YR 4/2) dry; moderate fine granular structure; very friable; slightly acid; abrupt smooth boundary.
A1--18 to 36 centimeters; very dark brown (10YR 2/2) fine sandy loam, dark grayish brown (10YR 4/2) dry; moderate fine granular structure; very friable; slightly acid; gradual smooth boundary.
A2--36 to 61 centimeters; very dark brown (10YR 2/2) fine sandy loam, very dark grayish brown (10YR 3/2) kneaded, grayish brown (10YR 5/2) dry; weak fine granular and weak fine subangular blocky structure; very friable; slightly acid; gradual smooth boundary.
A3--61 to 76 centimeters; very dark grayish brown (10YR 3/2) fine sandy loam, grayish brown (10YR 5/2) dry; some dark brown (10YR 3/3) peds in the lower part; weak fine subangular blocky and weak fine granular structure; very friable; slightly acid; gradual smooth boundary. (Combined thickness of the A horizon is 60 to 90 centimeters.)
BA--76 to 97 centimeters; dark brown (10YR 3/3) fine sandy loam, brown (10YR 5/3) dry; weak medium subangular blocky structure; very friable; very dark grayish brown (10YR 3/2) coats on faces of peds; slightly acid; gradual smooth boundary. (0 to 25 centimeters thick)
Bw--97 to 112 centimeters; brown (10YR 4/3) fine sandy loam; weak medium and coarse subangular blocky structure; very friable; some dark brown (10YR 3/3) coats on faces of peds; neutral; gradual smooth boundary. (10 to 25 centimeters thick)
2C1--112 to 127 centimeters; brown (10YR 4/3) loamy fine sand; single grain; loose; neutral; gradual smooth boundary. (0 to 20 centimeters thick)
2C2--127 to 152 centimeters; brown (10YR 5/3) loamy fine sand; single grain; loose; neutral.
TYPE LOCATION: Major Land resource Area (MLRA) 103-Central Iowa and Minnesota Till Prairies, Polk County, Iowa subset; about 6 miles north of Mitchellville; located about 1,320 feet west and 300 feet south of the northeast corner of section 13, T. 80 N., R. 22 W; USGS Mitchellville topographic quadrangle; lat. 41 degrees 44 minutes 44 seconds N. and long. 93 degrees 21 minutes 12 seconds W., NAD 83.
RANGE IN CHARACTERISTICS:
Thickness of mollic epipedon--60 to 100 centimeters
Depth to carbonates--150 to more than 203 centimeters
Clay content of the particle-size control section (weighted average)--10 to 16 percent
Sand content of the particle-size control section (weighted average)--60 to 80 percent
A horizon:
Hue--10YR
Value--2 or 3
Chroma--1 or 2
Texture--fine sandy loam or sandy loam
Clay content--10 to 18 percent
Sand content--55 to 75 percent
Reaction--slightly acid or neutral
Rock fragment content--0 to 10 percent
BA horizon (when present):
Hue--10YR
Value--3
Chroma--2 or 3
Texture--fine sandy loam
Clay content--10 to 16 percent
Sand content--60 to 80 percent
Reaction--slightly acid or neutral
Rock fragment content--0 to 10 percent
Bw horizon:
Hue--10YR
Value--3 to 5
Chroma--3 or 4
Texture--fine sandy loam or sandy loam
Clay content--10 to 16 percent
Sand content--60 to 80 percent
Reaction--slightly acid or neutral
Rock fragment content--0 to 10 percent
Some pedons have 2E and Bt horizons
2C horizon:
Hue--10YR
Value--4 or 5
Chroma--3 to 6
Texture--loamy fine sand, fine sand, loamy sand or sand
Clay content--2 to 8 percent
Sand content--75 to 95 percent
Reaction--slightly acid to slightly alkaline
Rock fragment content--0 to 10 percent
COMPETING SERIES: These are the
Disco,
Eyota,
Hanlon,
Lomax,
Shellwood, and
Tomall series.
Disco--have a reaction class range of strongly acid or moderately acid in the middle third of the series control section
Eyota--have a sand content that averages 25 to 55 percent in the particle-size control section
Hanlon--have a mollic epipedon 100 to 180 centimeters thick and have a matrix chroma of 1 or 2 throughout the series control section
Lomax--have a sand content that averages 35 to 50 percent in the particle-size control section
Shellwood--have carbonates throughout the series control section
Tomall--have carbonates in the lower third of the series control section and have a rock fragment content of 0 to 35 percent in the lower third of the series control section
GEOGRAPHIC SETTING:
Parent material--alluvium or eolian sediments
Landform--base slopes, alluvial fans, high flood plains, and on treads and risers on stream terraces
Slope--0 to 5 percent
Elevation--155 to 460 meters above sea level
Mean annual air temperature--6 to 11 degrees C
Mean annual precipitation--585 to 965 millimeters
Frost-free period--145 to 205 days
GEOGRAPHICALLY ASSOCIATED SOILS: Members of the typical catena include
Coland,
Dickinson,
Sparta, and
Terril soils.
Coland--are at lower landscape positions on floodplains and are frequently saturated at the soil surface during the wettest periods of normal years
Dickinson--are in landscape positions similar to those of the Ankeny soils and have mollic epipedons 30 to 60 centimeters thick
Sparta--are in landscape positions similar to those of the Ankeny soils on stream terraces and are at higher elevations on uplands and have a sand content that averages more than 85 percent in the particle-size control section
Terril--are in landscape positions similar to those of the Ankeny soils on base slopes and have a clay content that averages 18 to 27 percent in the particle-size 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 in normal years
Saturated hydraulic conductivity--10.00 to 100.00 micrometers per second
Surface runoff potential--negligible or very low
Flooding--occasional or rarely flooded for very brief or brief periods during the months of February to November from precipitation events and snowmelt
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--Wisconsin driftless section, Dissected till plains
MLRAs--Central Iowa and Minnesota Till Prairies (103),
Eastern Iowa and Minnesota Till Prairies (104),
Northern Mississippi Valley Loess Hills (105), and
Illinois and Iowa Deep Loess and Drift (108)
LRR M; central and north-central Iowa and southern Minnesota
Extent--small
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: St. Paul, Minnesota
SERIES ESTABLISHED: Polk County, Iowa, 1958.
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 surface to a depth of 97 centimeters (Ap, A1, A2, A3, and BA horizons);
cambic horizon--the zone from a depth of 76 to 112 centimeters (BA and Bw horizons);
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, tenth edition, 2006.