LOCATION WINTERSET               IA+MO

Established Series
Rev. RID-DMG-JRH
09/2016

WINTERSET SERIES

The Winterset series consists of very deep, poorly drained soils formed in loess. These soils are on interfluves on dissected till plains and treads on stream terraces in river valleys. Slope ranges from 0 to 2 percent. Mean annual air temperature is about 11 degrees C. Mean annual precipitation is about 850 millimeters.

TAXONOMIC CLASS: Fine, smectitic, mesic Vertic Argiaquolls

TYPICAL PEDON: Winterset silty clay loam, on a slope of less than 1 percent, in a cultivated field, at an elevation of 358 meters above sea level. (Colors are for moist soil unless otherwise noted.)

Ap--0 to 18 centimeters; black (10YR 2/1) silty clay loam, very dark gray (10YR 3/1) dry; weak medium subangular blocky structure; friable; neutral; clear smooth boundary.

A--18 to 48 centimeters; black (10YR 2/1) silty clay loam, very dark gray (10YR 3/1) dry; moderate fine granular structure in the upper part and moderate fine subangular blocky in lower part; friable; few fine distinct dark yellowish brown (10YR 4/4) accumulations (oxides); moderately acid; gradual smooth boundary. (Combined thickness of the A horizon is 40 to 60 centimeters.)

Btg1--48 to 64 centimeters; very dark gray (10YR 3/1) silty clay, gray (10YR 5/1) dry; moderate very fine subangular blocky structure; firm; few distinct very dark gray (10YR 3/1) clay films on faces of peds; common fine faint dark grayish brown (10YR 4/2) redoximorphic depletions; few fine distinct dark yellowish brown (10YR 4/4) iron accumulations; moderately acid; gradual smooth boundary.

Btg2--64 to 81 centimeters; dark grayish brown (10YR 4/2) silty clay; faces of peds dark gray (10YR 4/1) and very dark gray (10YR 3/1); weak medium prismatic structure parting to moderate very fine subangular blocky; firm; common distinct very dark gray (10YR 3/1) clay films on faces of peds; many fine black (10YR 2/1) manganese concretions at 69 centimeters and below; common fine distinct olive brown (2.5Y 4/4) and yellowish brown (10YR 5/4) redoximorphic concentrations; slightly acid; gradual smooth boundary.

Btg3--81 to 99 centimeters; grayish brown (2.5Y 5/2) and yellowish brown (10YR 5/4) silty clay loam; faces of peds dark gray (5Y 4/1); moderate medium prismatic structure parting to moderate fine subangular blocky; firm; common distinct very dark gray (10YR 3/1) clay films on faces of peds; common fine distinct dark yellowish brown (10YR 4/4) redoximorphic concentrations; many fine black (10YR 2/1) manganese concretions; moderately acid; gradual smooth boundary.

Btg4--99 to 147 centimeters; olive gray (5Y 5/2) silty clay loam; faces of peds dark gray (5Y 4/1), gray (5Y 5/1), and some very dark gray (10YR 3/1); moderate medium prismatic structure parting to moderate medium subangular blocky; friable; common fine prominent yellowish brown (10YR 5/6) and common fine distinct olive brown (2.5Y 4/4) redoximorphic concentrations; common distinct clay films on faces of peds; slightly acid; gradual smooth boundary.

Btg5--147 to 200 centimeters; gray (5Y 5/1) and olive gray (5Y 5/2) silty clay loam; few fine prominent tongues of strong brown (7.5YR 5/6); moderate very coarse subangular blocky structure; friable; very few very dark clay films on prism faces and along surfaces of pores; few saucer-shaped clay bodies 5 to 10 millimeters in diameter; few fine black (10YR 2/1) manganese concretions; common fine distinct yellowish brown (10YR 5/4) and yellowish brown (10YR 5/6) redoximorphic concentrations; neutral.

TYPE LOCATION: Major Land Resource Area (MLRA) 108D-Illinois and Iowa Deep Loess and Drift, Western Part, Madison County, Iowa subset; about 5 miles west of Winterset; located about 483 feet west and 336 feet south of the northeast corner of section 6, T. 75 N., R. 28 W.; USGS Winterset topographic quadrangle; lat. 41 degrees 19 minutes 46 seconds N. and long. 94 degrees 6 minutes 39 seconds W., NAD 83.

RANGE IN CHARACTERISTICS:
Thickness of mollic epipedon--40 to 60 centimeters
Depth to carbonates--greater than 150 centimeters
Clay content in the particle-size control section (weighted average)--36 to 42 percent
Sand content in the particle-size control section (weighted average)--less than 5 percent
Rock fragment content-0 percent
Sodium adsorption ratio--0 percent

Ap or A horizon:
Hue--10YR or is neutral
Value--2
Chroma--0 or 1
Texture--silt loam or silty clay loam
Clay content--25 to 40 percent
Sand content--less than 5 percent
Reaction--moderately acid to neutral

Bt or Btg horizon:
Hue--10YR to 5Y
Value--3 to 6
Chroma--1 or 2
Texture--silty clay loam or silty clay
Clay content--35 to 44 percent
Sand content--less than 5 percent
Reaction--moderately acid to neutral

BCg horizon (when present):
Hue--2.5Y or 5Y
Value--4 to 6
Chroma--1 or 2
Texture--silty clay loam
Clay content--28 to 35 percent
Sand content--less than 5 percent
Reaction--moderately acid to neutral

Cg or C horizon (when present):
Hue--2.5Y or 5Y
Value--4 to 6
Chroma--1 or 2
Texture--silt loam or silty clay loam
Clay content--25 to 35 percent
Sand content--less than 5 percent
Reaction--slightly acid to slightly alkaline

COMPETING SERIES: These are the Butler, Carbika, Chancellor, Clarinda, Coatsburg, Edinburg, Fosterburg, Haig, Lodgepole, Mazaska, Minnetonka, Olbut, Sacville, Sampsel, Taintor, Terrabella, Virden, and Worthing series.
Butler--have a clay content that averages 45 to 55 percent in the particle-size control section
Carbika--are in areas that have a mean annual air temperature range of 13 to 14 degrees C and have sand content of more than 20 percent in the lower third of the series control section
Chancellor--have mollic epipedons 61 to 102 centimeters thick
Clarinda--have a clay content that averages 40 to 60 percent in the particle-size control section
Coatsburg--have a sand content that averages 15 to 35 percent in the particle-size control section
Edinburg--have an average clay content of less than 32 percent in the upper third of the series control section - see remarks
Fosterburg--have a sodium adsorption ratio of 5 to 15 percent in the middle third of the series control section
Haig--have mollic epipedons 51 to 71 centimeters thick and have a clay content of 40 to 50 percent in the lower third of the series control section
Lodgepole--have mollic epipedons 51 to 127 centimeters thick
Mazaska--have carbonates within a depth of 152 centimeters and have a rock fragment content of 2 to 8 percent in the series control section
Minnetonka--have carbonates within a depth of 132 centimeters
Olbut--have salt accumulations within the series control section
Sacville--have a rock fragment content of 1 to 60 percent in the lower third of the series control section
Sampsel--have a paralithic contact with shale within a depth of 203 centimeters
Taintor--differentia is unclear, see remarks
Terrabella--have matrix hues of 5YR or 7.5YR in the middle third of the series control section and have a clay content that averages 40 to 55 percent in the particle-size control section
Virden--are in areas that have a mean annual air temperature range of 11 to 14 degrees C and a mean annual precipitation range of 860 to 1,140 millimeters - see remarks
Worthing--have mollic epipedons greater than 89 centimeters thick

GEOGRAPHIC SETTING:
Parent material--loess
Landform--interfluves on dissected till plains and treads on stream terraces in river valleys
Slope--0 to 2 percent
Elevation--185 to 475 meters above sea level
Mean annual temperature--8 to 13 degrees C
Mean annual precipitation--660 to 1,040 millimeters
Frost-free period--155 to 220 days

GEOGRAPHICALLY ASSOCIATED SOILS: These are the Clearfield, Macksburg, Sharpsburg and Sperry soils.
Clearfield--are on lower landscape positions on side slopes and have a clay content of 35 to 65 percent in the lower third of the series control section
Macksburg--are on slightly higher landscape positions and have a frequently saturated zone between depths of 0.3 and 1.0 meter during the wettest periods of years when precipitation is within one standard deviation of the 30 year mean of annual precipitation
Sharpsburg--are on lower landscape positions on narrow ridgetops and side slopes and have a frequently saturated zone between depths of 1.2 and 1.8 meters during the wettest periods of years when precipitation is within one standard deviation of the 30 year mean of annual precipitation
Sperry--are on lower landscape positions in small depressions and have an albic horizon

DRAINAGE AND SATURATED HYDRAULIC CONDUCTIVITY:
Drainage class--poorly drained--these soils are frequently saturated at the soil surface to a depth of 0.3 meter during the wettest periods of years when precipitation is within one standard deviation of the 30 year mean of annual precipitation, this saturation is considered apparent
Saturated hydraulic conductivity--0.01 to 10.00 micrometers per second

USE AND VEGETATION:
Most areas are cultivated. The principal crops are corn and soybeans. The native vegetation is big bluestem, western wheatgrass, sedges, blue grama, and other species of the tall grass prairie that are tolerant of excessive wetness. See Additional Data section for native vegetative cover in Iowa.

DISTRIBUTION AND EXTENT:
Physiographic Division--Interior Plains
Physiographic Province--Central Lowland
Physiographic Section--Dissected till plains
MLRAs--Iowa and Missouri Deep Loess Hills (107B) and Illinois and Iowa Deep Loess and Drift, Western Part (108D)
LRR--M; South-central Iowa and northwest Missouri
Extent--moderate

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

SERIES ESTABLISHED: Taylor County, Iowa, 1948.

REMARKS:
Particle-size control section--the zone from a depth of 48 to 98 centimeters;
series control section--the zone from the surface to a depth of 200 centimeters.

Diagnostic horizons and features recognized in this pedon include:
mollic epipedon--the zone from the surface to a depth of 64 centimeters (Ap, A, and Btg1 horizons);
argillic horizon--the zone from a depth of 48 to 200 centimeters (Btg1, Btg2, Btg3, Btg4 and Btg5 horizons);
aquic moisture regime.

Further study is needed to differentiate Edinburg, Taintor, Virden and Winterset series.

This update changes the classification from fine, smectitic, mesic Typic Argiaquolls. The linear extensibility is 6.04 centimeters between the surface and a depth of 100 centimeters. The classification of one the most common associates, Macksburg series, was recently changed to fine, smectitic, mesic Aquertic Argiudolls, based on linear extensibility.

Taxonomy version--Keys to Soil Taxonomy, twelfth edition, 2014.

ADDITIONAL DATA:
Laboratory data--Iowa State University, Ames Iowa
Laboratory data--Kellogg Soil Survey Laboratory, Lincoln, Nebraska user pedon ID numbers 1961IA121003, 1961IA121002, 1982MO195006m.

In Iowa, 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. Source: Iowa State Office, Natural Resources Conservation Service, Des Moines, IA.

---

National Cooperative Soil Survey
U.S.A.