LOCATION TERRIL                  IA+IL MN WI

Established Series
Rev. CSF-KMG-TWN
03/2015

TERRIL SERIES

The Terril series consists of very deep, well and moderately well drained soils formed in colluvium. These soils are on base slopes, foot slopes, drainageways, swales and toe slopes on alluvial fans, and treads and risers on stream terraces. Slope ranges from 0 to 25 percent. Mean annual air temperature is about 10 degrees C. Mean annual precipitation is about 875 millimeters.

TAXONOMIC CLASS: Fine-loamy, mixed, superactive, mesic Cumulic Hapludolls

TYPICAL PEDON: Terril loam, on a foot slope of about 4 percent, in a cultivated field. (Colors are for moist soil unless otherwise indicated.)

Ap--0 to 23 centimeters; black (10YR 2/1) loam, very dark gray (10YR 3/1) dry; weak fine subangular blocky structure parting to moderate fine and medium granular; friable; neutral; abrupt smooth boundary.

A1--23 to 38 centimeters; black (10YR 2/1) loam, very dark gray (10YR 3/1) dry; a few peds of very dark brown (10YR 2/2); weak very fine and fine subangular blocky structure parting to moderate fine and medium granular; friable; neutral; gradual smooth boundary.

A2--38 to 58 centimeters; black (10YR 2/1) loam, very dark gray (10YR 3/1) dry; weak medium prismatic structure parting to fine and medium subangular blocky; friable; neutral; gradual smooth boundary.

A3--58 to 81 centimeters; black (10YR 2/1) and very dark gray (10YR 3/1) loam, very dark gray (10YR 3/1) dry; weak medium prismatic structure parting to weak fine and medium subangular blocky; friable; neutral; gradual smooth boundary.

A4--81 to 91 centimeters; very dark brown (10YR 2/2) and very dark grayish brown (10YR 3/2) loam, dark grayish brown (10YR 4/2) and very dark grayish brown (10YR 3/2) dry; weak medium prismatic structure parting to moderate fine and medium subangular blocky; friable; neutral; clear smooth boundary. (Combined thickness of the A horizon is 60 to 150 centimeters.)

Bw1--91 to 109 centimeters; brown (10YR 4/3) loam; weak medium prismatic structure parting to weak fine and medium subangular blocky; friable; few fine tubular pores; common distinct very dark grayish brown (10YR 3/2) coats on faces of peds; neutral; gradual smooth boundary.

Bw2--109 to 127 centimeters; dark yellowish brown (10YR 4/4) loam; weak medium prismatic structure parting to weak medium subangular blocky; friable; few fine tubular pores; common dark yellowish brown (10YR 3/4) and few very dark grayish brown (10YR 3/2) coats on faces of peds; neutral; gradual smooth boundary. (Combined thickness of the Bw horizon is 10 to 50 centimeters.)

BC--127 to 152 centimeters; dark yellowish brown (10YR 4/4) loam; weak medium prismatic structure; friable; common fine tubular pores; neutral.

TYPE LOCATION: Major Land Resource Area (MLRA) 103-Central Iowa and Minnesota Till Prairies; Emmet County, Iowa subset; located about 600 feet east and 60 feet south of the northwest corner of section 25, T. 99 N., R. 34 W.; USGS Wallingford quadrangle, lat. 43 degrees 22 minutes 13 seconds N. and long. 94 degrees 48 minutes 50 seconds W., NAD 83.

RANGE IN CHARACTERISTICS:
Thickness of mollic epipedon--60 to 150 centimeters
Depth to carbonates--more than 100 centimeters
Clay content of the particle-size control section (weighted average)--18 to 27 percent
Sand content of the particle-size control section (weighted average)--25 to 60 percent

A horizon:
Hue--10YR
Value--2 or 3
Chroma--1 or 2
Texture--loam, silt loam high in sand, or clay loam
Clay content--18 to 30 percent
Sand content--15 to 40 percent
Rock fragment content--0 to 5 percent
Reaction--slightly acid or neutral

Some pedons have an AB or BA horizon

Bw and BC horizons:
Hue--10YR or 2.5Y
Value--3 or 4
Chroma--3 or 4
Texture--loam, clay loam, or sandy loam
Clay content--18 to 30 percent
Sand content--25 to 60 percent
Rock fragment content--0 to 5 percent
Reaction--slightly acid or neutral

Some pedons have a Bk horizon

C horizon (when present):
Hue--10YR or 2.5Y
Value--4 or 5
Chroma--3 or 4
Texture--loam, clay loam, or sandy clay loam
Clay content--15 to 30 percent
Sand content--25 to 60 percent
Rock fragment content--0 to 5 percent
Reaction--slightly acid to moderately alkaline

COMPETING SERIES: These are the Dameron, Deloit, Du Page, Fort Dodge, Olmitz, Racket, Ross, Spillco, Spillville, and Turlin series.
Dameron--have a rock fragment content of more than 15 percent within a depth of 100 centimeters
Deloit--do not have a frequently saturated zone within a depth of 1.8 meters during the wettest periods of years when precipitation is within one standard deviation of the 30 year mean of annual precipitation
Du Page--have carbonates within a depth of 25 centimeters
Fort Dodge--have a sand content of 75 to 95 percent in the lower third of the series control section
Olmitz--have a clay content that averages 28 to 34 percent in the particle-size control section
Racket--have a rock fragment content of more than 15 percent in the lower third of the series control section
Ross--do not have a frequently saturated zone within a depth of 1.8 meters during the wettest periods of years when precipitation is within one standard deviation of the 30 year mean of annual precipitation
Spillco--have carbonates within a depth of 90 centimeters
Spillville--have a frequently saturated zone within depths of 0.3 to 0.6 meters during the wettest periods of years when precipitation is within one standard deviation of the 30 year mean of annual precipitation and have a clay content of 5 to 24 percent in the lower third of the series control section
Turlin--have a frequently saturated zone within depths of 0.3 to 0.9 meters during the wettest periods of years when precipitation is within one standard deviation of the 30 year mean of annual precipitation and have a clay content of 8 to 18 percent in the lower third of the series control section

GEOGRAPHIC SETTING:
Parent material--colluvium
Landform--base slopes, foot slopes, drainageways, swales and toe slopes on alluvial fans, and treads and risers on stream terraces
Slopes--0 to 25 percent
Elevation--105 to 610 meters above sea level
Mean annual air temperature--6 to 14 degrees C
Mean annual precipitation--585 to 1,170 millimeters
Frost-free period--145 to 225 days

GEOGRAPHICALLY ASSOCIATED SOILS: These are the Clarion, Colo, Lester, and Storden soils.
Clarion--are on higher landscape positions on side slopes and have a mollic epipedon 25 to 56 centimeters thick
Colo--are on lower landscape positions on toe slopes and in floodplains and have a frequently saturated zone within 0.3 meters during the wettest periods of years when precipitation is within one standard deviation of the 30 year mean of annual precipitation
Lester--are on higher landscape positions on side slopes and have dark-colored surface layers 15 to 25 centimeters thick
Storden--are on higher landscape positions on side slopes and have carbonates throughout the series control section

DRAINAGE AND SATURATED HYDRAULIC CONDUCTIVITY:
Drainage class--moderately well drained--a frequently saturated zone occurs within depths of 1 to 1.8 meters during the wettest periods of years when precipitation is within one standard deviation of the 30 year mean of annual precipitation
Saturated hydraulic conductivity--1.0 to 10.0 micrometers per second

USE AND VEGETATION:
Many areas next to steep slopes or bottom land are in permanent pasture. Other areas are cultivated. The principal crops are corn, legume meadow, oats, and soybeans. 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--Western lake section, Wisconsin driftless section, Dissected till plains, and Till plains
MLRAs--Till Plains (102B),
Loess Uplands (102C),
Central Iowa and Minnesota Till Prairies (103),
Eastern Iowa and Minnesota Till Prairies (104),
Northern Mississippi Valley Loess Hills (105),
Iowa and Minnesota Loess Hills (107A),
Iowa and Missouri Deep Loess Hills (107B),
Illinois and Iowa Deep Loess and Drift, East-Central Part (108B),
Illinois and Iowa Deep Loess and Drift, West-Central Part (108C),
Southern Illinois and Indiana Thin Loess and Till Plain, Western Part (114B), and
Central Mississippi Valley Wooded Slopes, Northern Part (115C)
LRR M; North-central Iowa, Illinois, south-central Minnesota, and Wisconsin
Extent--large

MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: ST. PAUL, MINNESOTA

SERIES ESTABLISHED: Dickinson County, Iowa, 1944

REMARKS:
Particle-size control section--the zone from a depth of 25 to 100 centimeters (A1, A2, A3, A4, and Bw1 horizons);
series control section--the zone from the surface to a depth of 150 centimeters (Ap, A1, A2, A3, A4, Bw1, Bw2, and BC horizons).

Diagnostic horizons and features recognized in this pedon:
mollic epipedon--the zone from the surface to a depth of 91 centimeters (Ap, A1, A2, A3, and A4 horizons);
cambic horizon--the zone from a depth of 91 to 152 centimeters (Bw1, Bw2, and BC horizons);
udic moisture regime.

A firm till substratum phase is recognized in MLRA 103 on the Coteau Slope (bench) physiographic area.

Cation-exchange class is inferred from lab data for similar soils in the surrounding area.

Taxonomy version--Keys to Soil Taxonomy, tenth edition, 2006.

ADDITIONAL DATA:
Laboratory data--Iowa State University, Ames, Iowa

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National Cooperative Soil Survey
U.S.A.