LOCATION CLEARFIELD IA

Established Series
Rev. FFR-DBO-DJP
07/2018

CLEARFIELD SERIES

The Clearfield series consists of very deep, poorly drained soils formed in 100 to 150 centimeters of Wisconsin Age loess underlain by a gleyed Yarmouth-Sangamon paleosol. These soils are on linear to slightly convex side slopes and head slopes on dissected till plains. Slope ranges from 5 to 14 percent. Mean annual air temperature is about 10 degrees C. Mean annual precipitation is about 940 millimeters.

TAXONOMIC CLASS: Fine, smectitic, mesic Typic Endoaquolls

TYPICAL PEDON: Clearfield silty clay loam, on a west-facing slope of about 6 percent, in a cultivated field, at an elevation of 393 meters above sea level. (Colors are for moist soil unless otherwise stated.)

Ap--0 to 18 centimeters; black (10YR 2/1) silty clay loam, very dark gray (10YR 3/1) dry; weak fine subangular blocky structure parting to weak fine granular; friable; common roots; slightly acid; abrupt smooth boundary.

A1--18 to 33 centimeters; black (10YR 2/1) silty clay loam, very dark gray (10YR 3/1) dry; moderate fine and very fine subangular blocky structure; friable; moderately acid; clear smooth boundary.

A2--33 to 43 centimeters; very dark gray (10YR 3/1) silty clay loam, dark gray (10YR 4/1) dry; moderate very fine subangular blocky structure; friable; few fine distinct yellowish brown (10YR 5/4) redoximorphic concentrations; moderately acid; gradual smooth boundary. (Combined thickness of the A horizon is 25 to 49 centimeters.)

Btg1--43 to 64 centimeters; dark gray (10YR 4/1) silty clay loam, dark grayish brown (2.5Y 4/2) kneaded; weak medium subangular blocky structure parting to weak fine subangular blocky; firm; common distinct very dark gray (10YR 3/1) clay films on faces of peds; black (10YR 2/1) coats along surface of root channels and pores; few dark concretions (manganese oxides); many fine prominent reddish brown (2.5YR 4/4) redoximorphic concentrations; slightly acid; gradual smooth boundary.

Btg2--64 to 79 centimeters; olive gray (5Y 5/2) silty clay loam; moderate medium subangular blocky structure; firm; common distinct dark gray (5Y 4/1) clay films on faces of peds; few dark concretions (manganese oxides); common fine distinct dark gray (10YR 4/1) redoximorphic depletions; few fine prominent brown (7.5YR 4/4), yellowish brown (10YR 5/6) and yellowish brown (10YR 5/8) redoximorphic concentrations; moderately acid; gradual smooth boundary.

Btg3--79 to 99 centimeters; gray (5Y 5/1) silty clay loam; weak medium prismatic structure parting to moderate medium subangular blocky; friable; common distinct dark gray (5Y 4/1) clay films on faces of prisms; few medium faint gray (10YR 5/1) redoximorphic depletion; many medium prominent strong brown (7.5YR 5/6) and strong brown (7.5YR 5/8) redoximorphic concentrations; slightly acid; clear smooth boundary. (Combined thickness of the Btg horizon is 30 to 70 centimeters.)

Bg1--99 to 122 centimeters; gray (5Y 6/1) silty clay loam; weak medium prismatic structure parting to weak fine subangular blocky; friable; a concentrated area of dark concretions (manganese oxides) in the upper 10 centimeters of this horizon; many medium prominent yellowish brown (10YR 5/4) redoximorphic concentrations; slightly acid; abrupt smooth boundary.

Bg2--122 to 137 centimeters; dark gray (N 4/) silty clay loam; weak medium subangular blocky structure; firm; few thin layers of gray (10YR 6/1) silty clay loam; few fine prominent brownish yellow (10YR 6/6), brown (7.5YR 4/4) and yellowish red (5YR 5/8) redoximorphic concentrations; moderately acid; abrupt smooth boundary. (Combined thickness of the Bg horizon is 30 to 45 centimeters.)

2Abg--137 to 163 centimeters; black (10YR 2/1) silty clay loam; massive dissected by few oblique fractures; firm; slightly acid; gradual smooth boundary. (0 to 36 centimeters thick)

2Bbg--163 to 180 centimeters; dark gray (10YR 4/1) silty clay; massive; firm; few fine faint dark grayish brown (10YR 4/2) redoximorphic concentrations; moderately acid.

TYPE LOCATION: Land Resource Unit (LRU) 108D-Illinois and Iowa Deep Loess and Drift, Western Part; Union County, Iowa; about 3 miles east and 2 miles south of Creston; about 1,400 feet south and 1,400 feet east of the northwest corner of sec. 21, T. 72 N., R. 30 W.; USGS Creston East topographic quadrangle; lat. 41 degrees 01 minutes 29 seconds N. and long .94 degrees 18 minutes 48 seconds W, NAD 83.

RANGE IN CHARACTERISTICS:
Depth to paleosol--100 to 150 centimeters
Depth to carbonates--more than 150 centimeters
Clay content in the particle-size control section (weighted average)--35 to 40 percent
Sand content in the particle-size control section (weighted average)--less than 5 percent

Ap or A horizon:
Hue--10YR or is neutral
Value--2, 2.5, or 3
Chroma--0 or 1
Texture--silty clay loam
Clay content--32 to 38 percent
Sand content--less than 5 percent
Reaction--moderately acid to neutral

Btg and Bg horizons:
Hue--10YR to 5Y, or is neutral
Value--4 to 6
Chroma--0 to 2
Texture--silty clay loam or silty clay
Clay content--32 to 42 percent
Sand content--less than 5 percent
Reaction--moderately acid to neutral

2Ab horizon:
Hue--10YR or is neutral
Value--2, 2.5, or 3
Chroma--0 or 1
Texture--silty clay, silty clay loam, or clay
Clay content--35 to 65 percent
Sand content--less than 10 percent
Reaction--strongly acid to slightly acid

2Bbg horizon:
Hue--10YR to 5Y, or is neutral
Value--4 to 6
Chroma--0 or 1
Texture--silty clay or clay
Clay content--40 to 65 percent
Sand content--less than 10 percent
Reaction--strongly acid to slightly acid

COMPETING SERIES: There are no other series in this family.

GEOGRAPHIC SETTING:
Parent material--100 to 150 centimeters of Wisconsin Age loess underlain by a gleyed Yarmouth-Sangamon paleosol
Landform--linear to slightly convex side slopes and head slopes on dissected till plains
Slope--5 to 14 percent
Elevation--155 to 460 meters above sea level
Mean annual air temperature--8 to 12 degrees C
Mean annual precipitation--840 to 1,040 millimeters
Frost-free period--170 to 210 days

GEOGRAPHICALLY ASSOCIATED SOILS: These are the Clarinda, Nira, and Sharpsburg soils.
Clarinda--are on landscape positions similar to those of the Clearfield soils and have a clay content that averages 40 to 60 percent in the particle-size control section
Nira--are at higher landscape positions on side slopes and are frequently saturated at a depth of 0.4 meter during the wettest periods of normal years
Sharpsburg--are at higher landscape positions on side slopes and are frequently saturated at a depth of 1 meter during the wettest periods of normal years

DRAINAGE AND SATURATED HYDRAULIC CONDUCTIVITY:
Drainage class--poorly drained--these soils are frequently saturated at the soil surface during the wettest periods of normal years, these soils have side hill seeps during parts of the year
Saturated hydraulic conductivity--0.10 to 10.00 micrometers per second in the loess and 0.01 to 0.10 micrometers per second in the underlying paleosol
Potential surface runoff--medium

USE AND VEGETATION:
Most areas are cultivated. The principal crops are corn and soybeans. The native vegetative cover is a herbaceous wetland community commonly inhabited with Bluejoint Grasses, Fowl Bluegrasses, Green Muhlies, Fox Sedges, Field Sedges, Dudleys Rushes, Torreys Rushes, Swamp Milkweeds, False Sneezeweeds, False Asters, New England Asters, White Panicled Asters, and Wild Mints.

DISTRIBUTION AND EXTENT:
Physiographic Division--Interior Plains
Physiographic Province--Central Lowland
Physiographic section--Dissected till plains
MLRAs and LRUs--Illinois and Iowa Deep Loess and Drift, Western Part (108D); Illinois and Iowa Deep Loess and Drift, West-Central Part (108C); and Iowa and Missouri Heavy Till Plain (109)
LRR--M; southwestern and southern Iowa
Extent--moderate

MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Indianapolis, Indiana.

SERIES ESTABLISHED: Taylor County, Iowa, 1948.

REMARKS:
Diagnostic horizons and features recognized in this pedon include:
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 180 centimeters.
Mollic epipedon--the zone from the surface to a depth of 43 centimeters (Ap, A1, and A2 horizons).
Cambic horizon--the zone from a depth of 43 to 137 centimeters.(Btg1, Btg2, Btg3, Bg1 and Bg2 horizons).
Aquic moisture regime.

These soils were formerly classified as fine-silty, mixed, mesic Typic Argiaquolls. Available laboratory data indicate that most pedons do not meet the clay increase requirements for an argillic horizon. The weighted average clay content of the particle-size control section is marginal to the fine-silty family.

Taxonomy version--Keys to Soil Taxonomy, Twelfth Edition, 2014.

National Cooperative Soil Survey
U.S.A.