LOCATION WIOTA              IA+MO

WIOTA SERIES

TAXONOMIC CLASS: Fine-silty, mixed, superactive, mesic Pachic Argiudolls

TYPICAL PEDON: Wiota silty clay loam, on a convex slope of 3 percent, in a cultivated field. (Colors are for moist soil unless otherwise stated.)

Ap--0 to 20 centimeters; black (10YR 2/1) silty clay loam, dark gray (10YR 4/1) dry; weak fine granular structure; friable; many fine roots; common fine tubular pores; strongly acid; abrupt smooth boundary.

A1--20 to 38 centimeters; very dark gray (10YR 3/1) silty clay loam, dark gray (10YR 4/1) dry; weak fine and very fine granular structure; friable; common very fine roots; many very fine tubular pores; strongly acid; gradual smooth boundary.

A2--38 to 56 centimeters; very dark grayish brown (10YR 3/2) silty clay loam, gray (10YR 5/1) dry; moderate very fine subangular blocky structure; friable; common very fine roots; many very fine tubular pores; very many distinct very dark gray (10YR 3/1) organic stains on vertical faces of peds; moderately acid; gradual smooth boundary. (Combined thickness of the A horizon is 50 to 61 centimeters.)

AB--56 to 71 centimeters; about 80 percent very dark grayish brown (10YR 3/2) and about 20 percent dark brown (10YR 3/3) silty clay loam, grayish brown (10YR 5/2) dry; moderate fine subangular blocky structure; friable; common very fine roots; common very fine tubular pores; common distinct very dark gray (10YR 3/1) organic stains on vertical faces of peds; moderately acid; gradual smooth boundary. (0 to 15 centimeters thick)

Bt1--71 to 97 centimeters; brown (10YR 4/3) silty clay loam; moderate medium prismatic structure parting to moderate fine subangular blocky; friable; common very fine roots; common very fine tubular pores; common distinct dark brown (10YR 3/3) clay films on vertical faces of peds; moderately acid; gradual smooth boundary.

Bt2--97 to 122 centimeters; dark yellowish brown (10YR 4/4) silty clay loam; moderate medium prismatic structure parting to moderate medium subangular blocky; friable; common very fine roots; common very fine tubular pores; common distinct brown (10YR 4/3) clay films on vertical faces of peds; moderately acid; gradual smooth boundary.

Bt3--122 to 150 centimeters; dark yellowish brown (10YR 4/4) silty clay loam; moderate coarse prismatic structure parting to moderate coarse subangular blocky; friable; common fine roots; common very fine tubular pores; few distinct brown (10YR 4/3) clay films on vertical faces of peds; common fine distinct grayish brown (10YR 5/2) redoximorphic depletions; moderately acid; gradual smooth boundary. (Combined thickness of the Bt horizon is 60 to 120 centimeters.)

BC--150 to 178 centimeters; yellowish brown (10YR 5/4) silt loam; weak coarse prismatic structure; friable; common very fine tubular pores; common fine distinct grayish brown (10YR 5/2) redoximorphic depletions; moderately acid; clear smooth boundary. (0 to 36 centimeters thick)

C--178 to 203 centimeters; yellowish brown (10YR 5/4) silt loam; massive; friable; common very fine tubular pores; few medium distinct grayish brown (2.5Y 5/2) redoximorphic depletions; moderately acid.

TYPE LOCATION: Major Land Resource Area (MLRA) 108D-Illinois and Iowa Deep Loess and Drift, Western Part; Adams County, Iowa subset; about 1 mile south of Mt. Etna; located about 200 feet south and 2,145 feet east of the northwest corner of section 27, T. 73 N., R. 34. W.; USGS Corning North topographic quadrangle; lat. 41 degrees 6 minutes 2 seconds N. and long. 94 degrees 44 minutes 55 seconds W., NAD 83.

RANGE IN CHARACTERISTICS:
Thickness of the mollic epipedon--50 to 81 centimeters
Depth to carbonates--more than 203 centimeters
Clay content of the particle-size control section (weighted average)--30 to 35 percent
Sand content of the particle-size control section (weighted average)--5 to 15 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--20 to 32 percent
Sand content--less than 15 percent
Reaction--strongly acid to neutral

Bt horizon:
Hue--10YR
Value--3 to 5
Chroma--3 or 4
Texture--silty clay loam
Clay content--30 to 35 percent
Sand content--less than 15 percent
Reaction--strongly acid to slightly acid
B/A clay ratio--near 1.2

BC or C horizon:
Hue--10YR or 2.5Y
Value--4 or 5
Chroma--1 to 6
Texture--silty clay loam or silt loam
Clay content--25 to 34 percent
Sand content--less than 15 percent
Reaction-moderately acid or slightly acid

2C horizon (when present, below a depth of 150 centimeters):
Hue--10YR or 2.5Y
Value--4 or 5
Chroma--1 to 6
Texture--sandy loam, loamy sand, fine sand, sand or the gravelly analogs of these textures
Clay content--0 to 20 percent
Sand content--50 to 90 percent
Rock fragment content--0 to 15 percent
Reaction--slightly acid or neutral

COMPETING SERIES: These are the Barremills, Cotter, Reading, Sibley (see remarks), and Troxel series.
Barremills--have an average clay content of 18 to 27 percent in the particle-size control section and have a frequently saturated zone at a depth of 1 meter during the wettest periods of normal years
Cotter--have a clay content of 25 to 30 percent in the lower third of the argillic horizon and are in areas that have a mean annual air temperature range of 12 to 15 degrees C
Reading--have carbonates within depths of 102 to 203 centimeters and are in areas that have a mean annual air temperature range of 12 to 14 degrees C
Sibley--have a sand content of less than 5 percent in the particle-size control section
Troxel--have a sand content of more than 20 percent in the lower third of the series control section

GEOGRAPHIC SETTING:
Parent material--alluvium
Landform--treads and risers on stream terraces
Slope--0 to 5 percent
Elevation--198 to 335 meters above sea level
Mean annual air temperature--7 to 12 degrees C
Mean annual precipitation--750 to 920 millimeters
Frost-free period--130 to 186 days

GEOGRAPHICALLY ASSOCIATED SOILS: These are the Bremer, Colo, Nevin, and Zook soils.
Bremer--are at lower elevations on flood plains, have a clay content of 35 to 40 percent in the particle-size control section and have a frequently saturated zone at a depth of 0.3 meter during the wettest periods of normal years
Colo--are at lower elevations on flood plains and are frequently saturated at the soil surface during the wettest period of normal years
Nevin--are at slightly lower elevations on stream terraces and have a zone of saturation at a depth of 0.3 meter during the wettest periods of normal years
Zook--are at lower elevations on floodplains, have a clay content of 35 to 45 percent in the particle-size control section and are frequently saturated at the soil surface during the wettest period of normal years

DRAINAGE AND SATURATED HYDRAULIC CONDUCTIVITY:
Drainage class--moderately well draineda frequently saturated zone occurs at a depth of 1.2 meters during March to June in normal years and is considered apparent
Saturated hydraulic conductivity4.23 to 14.11 micrometers per second (moderately high or high)
Surface runoff potential--negligible to low
Flooding--rarely flooded for brief or very brief periods from 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, Till plains, and Dissected till plains
MLRAs--Eastern Iowa and Minnesota Till Prairies (104), Northern Mississippi Valley Loess Hills (105), Iowa and Missouri Deep Loess Hills (107), Illinois and Iowa Deep Loess and Drift (108), Iowa and Missouri Heavy Till Plain (109), and Central Mississippi Valley Wooded Slopes (115)
LRR M; southern and east-central Iowa and northern Missouri
Extent--moderate

MLRA OFFICE RESPONSIBLE: St. Paul, Minnesota

SERIES ESTABLISHED: Adams County, Iowa, 1960

REMARKS:
Particle-size control section--the zone from a depth of 71 to 121 centimeters (Bt1 and Bt2 horizons);
series control section--the zone from the surface to a depth of 150 centimeters (Ap, A1, A2, AB, Bt1, Bt2, and Bt3 horizons).

Diagnostic horizons and features recognized in this pedon:
mollic epipedon--the zone from the surface to a depth of 71 centimeters (Ap, A1, A2, and AB horizons);
argillic horizon--the zone from a depth of 71 to 150 centimeters (Bt1, Bt2, and Bt3 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, ninth edition, 2003

In parts of MLRA 108 this soil meets the well drained drainage class criteria as defined in Soil Survey Manual. Drainage class is a state interpretation.

Reclassification of Sibley series to fine-silty, mixed, superactive, mesic Pachic Argiudolls is proposed.