LOCATION OMADI                   NE+IA SD

Established Series
Rev. DAV, LGR, PTC, JFH
11/2020

OMADI SERIES

The Omadi series consists of very deep, moderately well drained soils formed in loamy alluvium on flood plains. Slopes range from 0 to 5 percent. The mean annual precipitation is about 660 millimeters (26 inches), and the mean annual temperature is about 9 degrees C (49 degrees F).

TAXONOMIC CLASS: Fine-silty, mixed, superactive, mesic Fluventic Hapludolls

TYPICAL PEDON: Omadi silt loam - cultivated. (Colors are for moist soil unless otherwise stated.)

Ap--0 to 18 centimeters (0 to 7 inches); black (10YR 2/1) silt loam, dark gray (10YR 4/1) dry; weak very fine granular structure; slightly hard, very friable; neutral; abrupt smooth boundary.

A--18 to 30 centimeters (7 to 12 inches); black (10YR 2/1) silt loam, dark gray (10YR 4/1) dry; weak medium subangular blocky structure parting to weak fine granular; slightly hard, very friable; neutral; abrupt smooth boundary. [Combined thickness of the A horizon is 23 to 38 centimeters (9 to 15 inches)]

AC--30 to 51 centimeters (12 to 20 inches); stratified dark gray (10YR 4/1) and very dark gray (10YR 3/1) silt loam, light gray (10YR 7/1) and gray (10YR 5/1) dry; weak medium subangular blocky structure with some platy structure characteristics due to stratification; slightly hard, very friable; strongly effervescent; lime disseminated throughout the mass; much worm activity; few fine faint strong brown (7.5YR 5/6) iron masses in the matrix; moderately alkaline; abrupt smooth boundary. [15 to 21 centimeters (6 to 8 inches) thick]

C1--51 to 97 centimeters (20 to 38 inches); stratified dark gray (10YR 4/1) and very dark grayish brown (10YR 3/2) silt loam, light gray (10YR 7/1) to grayish brown (10YR 5/2) dry; weak medium subangular blocky structure with some platy structure characteristics due to stratification; slightly hard, very friable; violently effervescent, lime disseminated throughout the mass; many medium distinct strong brown (7.5YR 5/6) iron masses in the matrix; moderately alkaline; abrupt smooth boundary. [41 to 61 centimeters (16 to 24 inches) thick]

C2--97 to 203 centimeters (38 to 80 inches); very dark gray (10YR 3/1) silt loam, grayish brown (10YR 5/2) dry; massive; slightly hard, very friable; many medium distinct strong brown (7.5YR 5/6) iron masses in the matrix; violently effervescent, lime disseminated throughout the mass and some soft lime modules; moderately alkaline.

TYPE LOCATION: Major Land Resource Area (MLRA) 107B (Iowa and Missouri Deep Loess Hills), Dakota County Nebraska subset; 3.2 kilometers (2 miles) northeast of Hubbard; 488 meters (1600 feet) south and 15 meters (50 feet) west of the northeast corner, sec. 13, T. 28 N., R. 7 E. Latitude 42 degrees 24 minutes 17 seconds north, longitude 96 degrees 33 minutes 4 seconds west, NAD 83.

RANGE IN CHARACTERISTICS:
Soil moisture: Udic moisture regime.
Mean annual soil temperature: 9 to 12 degrees C (49 to 54 degrees F)
Depth to secondary calcium carbonate: less than 25 centimeters (10 inches)
Depth to redox concentrations: 51 to 102 centimeters (20 to 40 inches)
Thickness of the solum: less than 51 centimeters (20 inches)

Particle-size control section (weighted average):
Clay content: 18 to 25 percent
Sand content: 0 to 10 percent

Ap or A horizon:
Hue: 10YR
Value: 2 or 3
Chroma: 1 or 2
Texture: silt loam or light silty clay loam
Clay content: 12 to 30 percent
Calcium carbonate equivalent: 0 to 20 percent
Reaction: neutral to moderately alkaline
Thickness: 23 to 38 centimeters (9 to 15 inches)

AC horizon:
Hue: 10YR
Value: 2 or 3 (strata of 4 or 5)
Chroma: 1 or 2
Redox concentrations: hue: 7.5YR; value: 5; chroma: 6 (few to many faint to distinct, on the faces of the stratification planes or in root channels.)
Texture: silt loam or light silty clay loam
Clay content: 18 to 30 percent
Calcium carbonate equivalent: 1 to 20 percent
Reaction: slightly or moderately alkaline
Thickness: 15 to 21 centimeters (6 to 8 inches)

C horizon:
Hue: 10YR
Value: 2 to 4
Chroma: 1 or 2
Redox concentrations: hue: 7.5YR; value: 5; chroma: 6 (few to many faint to distinct, on the faces of the stratification planes or in root channels.)
Texture: silt loam or light silty clay loam
Clay content: 18 to 30 percent
Calcium carbonate equivalent: 1 to 20 percent
Reaction: slightly or moderately alkaline
Note: In some pedons, layers containing more than 35 percent clay are at a depth below 102 centimeters (40 inches).

COMPETING SERIES: These are the:
Armiesburg soils are in areas of higher mean annual precipitation, and do not have free calcium carbonate in the solum.
Battleground soils occur in areas of higher mean annual precipitation.
Bismarckgrove soils do not have free carbonates above 102 to 152 centimeters (40 to 60 inches) and have higher mean annual precipitation and mean annual temperature.
Dozaville soils have carbonates at depths greater than 25 centimeters (10 inches) from the soil surface.
Dungan soils have a difference between average winter and average summer soil temperature of less than 9 degrees C (16 degrees F).

GEOGRAPHIC SETTING:
Parent material: stratified recent silty alluvium
Landform: flood plains of the Missouri River
Slopes: 0 to 5 percent
Elevation: 305 to 610 meters (1000 to 2000 feet)
Mean annual temperature: 8 to 11 degrees C (47 to 52 degrees F)
Mean annual precipitation: 560 to 740 millimeters (22 to 28 inches)
Frost-free period: 140 to 170 days.

GEOGRAPHICALLY ASSOCIATED SOILS:
Forney soils are fine, saturated in the series control section for longer periods and are slightly lower on the landscape.
Holly Springs are fine, saturated in the series control section for longer periods and are slightly lower on the landscape
Kennebec soils are on similar landscapes, but are also in upland drainageways.
Napier soils are less stratified, more sloping and are on slightly higher landscapes.

DRAINAGE AND SATURATED HYDRAULIC CONDUCTIVITY:
Drainage: Depth to seasonally saturated soil is 122 to 183 centimeters (4 to 6 feet).
Runoff: Low
Saturated hydraulic conductivity: 1.00 to 10.00 micrometers per second
Flooding: Rarely to occasionally

USE AND VEGETATION: Most areas are used to grow corn, soybeans and alfalfa.

DISTRIBUTION AND EXTENT: MLRAs 102C (Loess Uplands), 107A (Iowa and Minnesota Loess Hills), and 107B (Iowa and Missouri Deep Loess Hills) within the Central Feed Grains and Livestock Region (Land Resource Region M). The Omadi series is of moderate extent; the total extent is about 6500 hectares (16,000 acres).

SOIL SURVEY REGIONAL OFFICE (SSRO) RESPONSIBLE: INDIANAPOLIS, INDIANA

SERIES ESTABLISHED: Dakota County, Nebraska, 1972.

REMARKS: Diagnostic horizons and other features recognized in these soils are: mollic epipedon--the zone from 0 to 30 centimeters (0 to 12 inches - Ap and A horizons)
Particle-size control section: The zone from 25 to 100 centimeters (10 to 40 inches - A, AC, C1 and C2 horizons)

Note: The Omadi series was formerly classified as alluvial soil.

The assignment of the cation-exchange activity class is inferred from lab data from similar soils in the surrounding area.

The current soil classification requires further study and data review based on the current keys to taxonomy.

Taxonomic Version: Eighth edition, 1998

ADDITIONAL DATA:
Series T Value: 5
Surface K value: .32
Surface Wind Erodibility Group: 5
Surface Wind Erodibility Index: 56

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National Cooperative Soil Survey
U.S.A.