LOCATION ZOOK                    IA+IL KS MN MO NE

Established Series
Rev. TEF-RAL-DJP
03/2020

ZOOK SERIES

The Zook series consists of very deep, poorly drained and very poorly drained soils formed in alluvium. These soils are on flood plains and stream terraces in river valleys and in drainageways on uplands. Slope ranges from 0 to 5 percent. Mean annual air temperature is about 11 degrees C. Mean annual precipitation is about 900 millimeters.

TAXONOMIC CLASS: Fine, smectitic, mesic Cumulic Vertic Endoaquolls

TYPICAL PEDON: Zook silty clay loam, on a slope of less than 1 percent in a cultivated field, at an elevation of about 351 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 fine subangular blocky structure parting to weak fine granular; friable; slightly acid; abrupt smooth boundary.

A1--18 to 36 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; slightly acid; gradual smooth boundary.

A2--36 to 51 centimeters; black (10YR 2/1) silty clay loam, very dark gray (10YR 3/1) dry; moderate fine prismatic structure parting to moderate fine subangular blocky; firm; neutral; gradual smooth boundary.

A3--51 to 79 centimeters; very dark gray (10YR 3/1) silty clay, dark gray (10YR 4/1) dry; moderate medium prismatic structure parting to moderate fine subangular blocky; firm; neutral; gradual smooth boundary.

A4--79 to 97 centimeters; very dark gray (10YR 3/1) silty clay, dark gray (10YR 4/1) dry; moderate medium prismatic structure parting to moderate medium subangular blocky; firm; common fine distinct olive gray (5Y 4/2) redoximorphic depletions; neutral; gradual smooth boundary. (Combined thickness of the A horizon is 65 to 125 centimeters.)

Bg--97 to 132 centimeters; dark gray (5Y 4/1) silty clay loam; moderate medium prismatic structure parting to moderate medium subangular blocky; firm; few fine prominent strong brown (7.5YR 5/6) redoximorphic concentrations; neutral; gradual smooth boundary. (25 to 90 centimeters thick)

BCg--132 to 155 centimeters; about 70 percent dark gray (5Y 4/1) and about 30 percent gray (5Y 5/1) silty clay loam; moderate coarse prismatic structure; firm; common fine faint grayish brown (2.5Y 5/2) redoximorphic depletions; neutral; clear smooth boundary. (0 to 50 centimeters thick)

Cg--155 to 200 centimeters; olive gray (5Y 5/2) silty clay loam; massive; friable; common fine prominent very dark brown (10YR 2/2) manganese masses; common fine prominent yellowish brown (10YR 5/6) redoximorphic concentrations; neutral.

TYPE LOCATION: Land Resource Unit (LRU) 107B-Iowa and Missouri Deep Loess Hills; Cass County, Iowa; about 5 miles west of Atlantic; about 1,800 feet east and 210 feet north of the southwest corner of sec. 5, T. 76 N., R. 37 W.; USGS Walnut topographic quadrangle; lat. 41 degrees 24 minutes 17 seconds N. and long. 95 degrees 7 minutes 52 seconds W., NAD 83.

RANGE IN CHARACTERISTICS:
Thickness of the mollic epipedon--90 to more than 150 centimeters
Depth to redoximorphic concentrations--60 to 150 centimeters
Depth to carbonates--150 to more than 200 centimeters
Clay content in the particle-size control section (weighted average)--35 to 45 percent
Sand content in the particle-size control section (weighted average)--0 to 15 percent fine sand and sand coarser than fine sand
Sodium adsorption ratio--0
Rock fragment content--0 percent

These soils are not stratified in the zone from the surface of the soil to a depth of 1.2 meters

Ap and A horizons:
Hue--10YR or is neutral
Value--2, 2.5, or 3
Chroma--0 or 1
Texture--silty clay loam or silty clay
Clay content--32 to 45 percent
Sand content--less than 15 percent
Reaction--moderately acid to slightly alkaline

Matrix value of 3 or less extends to depths of more than 90 centimeters

Overwash phase (when present):
Thickness--15 to 50 centimeters
Hue--10YR
Value--2 or 3
Chroma--1 or 2
Texture--silt loam
Clay content--20 to 26 percent
Sand content--5 to 20 percent
Reaction--moderately acid to slightly alkaline

Bg horizon:
Hue--10YR to 5Y
Value--2 to 5
Chroma--1
Texture--silty clay loam or silty clay
Clay content--35 to 45 percent
Sand content--less than 15 percent
Reaction--slightly acid or neutral

BCg (when present) or Cg horizon:
Hue--10YR to 5Y
Value--2 to 5
Chroma--1 or 2
Texture--silty clay loam, silty clay, or silt loam
Clay content--20 to 45 percent
Sand content--less than 15 percent
Reaction--slightly acid or neutral

COMPETING SERIES: These are the Chehalem, Clamo, Derrynane, Okoboji, Peotone, Rantoul, Shiloh, Southbrook, Wabash, and Zoe series.
Chehalem--have matrix chroma of more than 1 in the Bg horizon
Clamo--have carbonates within a depth of 150 centimeters
Derrynane--have a sand content of more than 15 percent in the lower part of the series control section and have a rock fragment content of 2 to 8 percent in the lower third of the series control section
Okoboji--have carbonates within a depth of 150 centimeters
Peotone--have a mollic epipedon that is less than 90 centimeters thick
Rantoul--average more than 45 percent clay in the particle-size control section
Shiloh--occur in depressions on ground moraines; have overlapping soil properties with Zook soils within the series control section
Southbrook--have a sand content of more than 15 percent in the lower part of the series control section
Wabash--average more than 45 percent clay in the particle-size control section
Zoe--have horizons with concentrations of sodium within the series control section (sodium adsorption ration is 1 or more)

GEOGRAPHIC SETTING:
Parent material--alluvium
Landform--flood plains and stream terraces in river valleys and in drainageways on uplands
Slope--0 to 5 percent
Elevation--100 to 575 meters above sea level
Mean annual air temperature--6 to 17 degrees C
Mean annual precipitation--585 to 1,220 millimeters
Frost-free period--145 to 255 days

GEOGRAPHICALLY ASSOCIATED SOILS: These are the Bremer, Judson, Nodaway, and Wabash soils.
Bremer--are at slightly higher elevations, have a mollic epipedon 60 to 90 centimeters thick, and have an argillic horizon
Judson--are at higher elevations on footslopes, have a clay content of 30 to 35 percent in the particle-size control section, and do not have a saturated zone within a depth of 1.8 meters during in the wettest period of years when precipitation is within one standard deviation of the 30 year mean of annual precipitation
Nodaway--are at slightly higher elevations and do not have a mollic epipedon
Wabash--are in landscape positions similar to those of the Zook soils and have a clay content that averages 45 to 60 percent in the particle-size control section

DRAINAGE AND SATURATED HYDRAULIC CONDUCTIVITY:
Drainage class--very poorly drained and poorly drained--these soils are frequently saturated from 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
Saturated hydraulic conductivity--0.01 to 10.00 micrometers per second
Ponding--very poorly drained phase has ponding up to 0.3 meter for long duration during late winter and spring of years when precipitation is within one standard deviation of the 30 year mean of annual precipitation and after heavy precipitation events
Flooding--rare to frequent flooding for brief to long periods on floodplains or on stream terraces, and none to very frequent flooding in drainageways on uplands for brief to very brief duration

USE AND VEGETATION:
Where drained, 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, Minnesota, and Nebraska.

DISTRIBUTION AND EXTENT:
Physiographic Division--Interior Plains
Physiographic Province--Central Lowland
Physiographic sections--Western lake section, Wisconsin driftless section, Till plains, Dissected till plains, Osage plain
MLRAs--Till Plains (102B),
Central Iowa and Minnesota Till Prairies (103),
Eastern Iowa and Minnesota Till Prairies (104),
Northern Mississippi Valley Loess Hills (105),
Nebraska and Kansas Loess-Drift Hills (106),
Iowa and Missouri Deep Loess Hills (107),
Illinois and Iowa Deep Loess and Drift (108),
Iowa and Missouri Heavy Till Plain (109),
Northern Illinois and Indiana Heavy Till Plain (110),
Cherokee Prairies (112),
Central Claypan Areas (113),
Southern Illinois and Indiana Thin Loess and Till Plain (114), and
Central Mississippi Valley Wooded Slopes (115)
Local physiographic location--commonly some distance from the main stream channel adjacent to foot slopes or terrace escarpments, in places, Zook soils are dissected by tributary channels that dissect the flood plains
LRR M; Iowa, central Illinois, northern Missouri, eastern Nebraska, south central Minnesota, and eastern Kansas
Extent--large

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

SERIES ESTABLISHED: Monona County, Iowa, 1956.

REMARKS:
Diagnostic horizons and features recognized in this pedon include:
Particle-size control section--the zone from a depth 25 to 100 centimeters (A1, A2, A3, A4, and Bg horizons).
Series control section--the zone from the surface to a depth of 155 centimeters (Ap, A1, A2, A3, A4, Bg, and BCg horizons).
Mollic epipedon--the zone from the surface to a depth 97 centimeters (Ap, A1, A2, A3, and A4 horizons).
Cambic horizon--the zone from a depth of 97 to 155 centimeters (Bg and BCg horizons).
Aquic moisture regime.

Vertic subgroup based on linear extensibility greater than 6.0 centimeters between the surface and a depth of 100 centimeters.

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 ids S1971IA185001, S1996IA193021, and 97IA047006L.

In Iowa and Minnesota, the native vegetative cover is an herbaceous wetland community commonly inhabited with Prairie Cordgrasses, Bluejoint Grasses, Fox Sedges, Oval Sedges, Inland Rushes, New England Asters, Foxglove Penstemons, Cool Mountain Mints, Prairie Sundrops, Winged Loosestrifes, and Saw-Tooth Sunflowers. Source: Iowa State Office, Natural Resources Conservation Service, Des Moines, IA.

In Nebraska, the native vegetative cover is an herbaceous wetland community commonly inhabited with sedges (Carex emoryi, C. laeviconica, C. pellita, C. vulpinoidea), flat stem spikerush, (Eleocharis compressa), Kentucky bluegrass (Poa Pratensis), prairie cordgrass (Spartina pectinate). Source: Terrestrial Ecological Systems and Natural Communities of Nebraska, Version IV. S.B. Rolfsmeier and G. Steinauer. Nebraska Natural Heritage Program, Nebraska Game and Parks Commission, 2010.

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National Cooperative Soil Survey
U.S.A.