LOCATION GIBBON                  NE+KS

Established Series
Rev. SAS/JGA
12/2011

GIBBON SERIES

The Gibbon series consists of very deep, somewhat poorly drained soils that formed in stratified, calcareous alluvium. These soils are on flood plains in river valleys of Central Loess Plains, MLRA 75. Slopes range from 0 to 2 percent. Mean annual temperature is 12 degrees C (53 degrees F) and mean annual precipitation is 690 millimeters (27 inches) at the type location.

TAXONOMIC CLASS: Fine-silty, mixed, superactive, calcareous, mesic Fluvaquentic Endoaquolls

TYPICAL PEDON: Gibbon silty clay loam - with a slope of less than 1 percent, in a cultivated field. (Colors are for dry soil unless otherwise stated.)

Ap--0 to 13 centimeters (0 to 5 inches); dark gray (10YR 4/1) silty clay loam, very dark gray (10YR 3/1) moist; moderate very fine granular structure; slightly hard, friable; strong effervescence; moderately alkaline; abrupt smooth boundary.

A--13 to 28 centimeters (5 to 11 inches); very dark gray (10YR 3/1) silty clay loam, black (10YR 2/1) moist; moderate very fine granular structure; slightly hard, friable; strong effervescence; moderately alkaline; clear smooth boundary. (Combined thickness of the A horizon ranges from 25 to 51 centimeters (10 to 20 inches)

AC--28 to 46 centimeters (11 to 18 inches); gray (10YR 6/1) silty clay loam, dark gray (10YR 4/1) moist; moderate very fine granular structure; slightly hard, friable; few fine faint brownish and yellowish oxidized iron masses in the matrix; violent effervescence; moderately alkaline; clear smooth boundary. (0 to 25 centimeters (0 to 10 inches) thick)

Cg1--46 to 66 centimeters (18 to 26 inches); light brownish gray (10YR 6/2) silt loam, dark gray (10YR 4/1) moist; massive; soft, very friable; common medium distinct grayish, brownish and yellowish oxidized iron masses in the matrix, violent effervescence; moderately alkaline; clear smooth boundary. (15 to 30 centimeters (6 to 12 inches) thick)

Cg2--66 to 91 centimeters (26 to 36 inches); light gray (10YR 7/2) very fine sandy loam, light brownish gray (10YR 6/2) moist; massive; soft, very friable; common coarse prominent brownish oxidized iron masses in the matrix; strong effervescence; strongly alkaline; clear smooth boundary. (13 to 38 centimeters (5 to 15 inches) thick)

Cg3--91 to 200 centimeters (36 to 79 inches); light gray (10YR 7/2) fine sandy loam; grayish brown (10YR 5/2) moist; massive; soft, very friable; common coarse prominent brownish oxidized iron masses in the matrix; strong effervescence; strongly alkaline.

TYPE LOCATION: Webster County, Nebraska; 1.6 kilometers (1 mile) south and 2.4 kilometers (1 1/2 miles) west of Inavale; 933 meters (3060 feet) east and 21 meters (70 feet) south of the northwest corner, sec. 9, T. 1 N., R. 12 W. 7.5 USGS quad; Grand Island, NE. long. 40 degrees N., 4 minutes, 54 second, lat. 98 degrees, 40 minutes, 73 seconds W. NAD 83.

RANGE IN CHARACTERISTICS:
Soil moisture: aquic moisture regime, moist from December through April and intermittently moist from May through December. The driest months are July through September.
Depth to free calcium carbonate: 0 to 25 centimeters (0 to 10 inches)
Calcium carbonate equivalent: 5 to 15 percent in the control section.
Depth to redox concentrations: 25 to 50 centimeters (10 to 20 inches)
Depth to redox depletions: 40 to 80 centimeters (16 to 31 inches)
Depth to endosaturation: 30 to 90 centimeters (12 to 36 inches) November to June
Thickness of the mollic epipedon: 25 to 49 centimeters (10 to 19 inches)
Electrical Conductivity: 0 to 2 millimhos per centimeter
Particle-size control section (weighted average) clay content: 18 to 34 percent
Particle-size control section (weighted average) fine sands or coarser content: 0 to 14 percent

A or Ap horizon:
Hue: 10YR or 2.5Y
Value: 3 to 5 dry, 2 or 3 moist
Chroma: 1 or 2
Texture: silt loam, silty clay loam, very fine sandy loam, loam, or clay loam.
Clay content: 8 to 35 percent
Sand content: 5 to 85 percent
Reaction: Slightly alkaline or moderately alkaline.

AC horizon:
Hue: 10YR to 5Y
Value: 5 to 8 dry, 4 to 6 moist
Chroma: 1 or 2
Texture: Silt loam, clay loam, or silty clay loam.
Carbonate concretions: 5 to 15 percent.
Clay content: 20 to 32 percent
Sand content: 5 to 40 percent
Calcium carbonate equivalent: 5 to 15 percent in the control section.
Sodium Absorption Ratio: 0 to 5
Reaction: Slightly alkaline to strongly alkaline.

Cg horizon:
Hue: 10YR to 5Y
Value: 5 to 8 dry, 5 to 7 moist
Chroma: 1 or 2
Texture: Silt loam, clay loam, very fine sandy loam, fine sandy loam, or silty clay loam.
Stratified with loamy fine sand, loamy sand, or fine sand in some profiles below the depth of 100 centimeters (40 inches).
Clay content: 4 to 35 percent
Sand content: 5 to 75 percent
Calcium carbonate equivalent: 5 to 15 percent in the control section.
Sodium Absorption Ratio: 0 to 5
Reaction: Slightly alkaline to strongly alkaline.

COMPETING SERIES: These are the Colville, Kittitas, Pahranagat and Paranat series.
Colville soils are poorly drained and have a cambic horizon.
Kittitas soils have more than 15 percent exchangeable sodium in the mollic epipedon.
Pahranagat, and Paranat soils are poorly drained and have less carbonates throughout the series control section.

GEOGRAPHIC SETTING:
Parent material: alluvium
Landform: floddplains in river valleys
Slopes: 0 to 2 percent
Mean annual temperature: 10 to 13 degrees C (50 to 55 degrees F)
Mean annual precipitation: 510 to 850 millimeters (20 to 34 inches)
Frost-free period: 130 to 190 days.

GEOGRAPHICALLY ASSOCIATED SOILS: These are the Humbarger, Inavale, McCook, Munjor, Platte, and Wann soils.
Humbarger soils are on similar landforms and have greater than 15 percent fine sand or coarser in the particle size control section (fine-loamy).
Inavale and Platte soils are on similar landforms and have a sandy particle size control section.
Munjor and Wann soils are on similar landforms and have greater than 15 percent fine sand or coarser and less than 18 percent clay in the particle size control section (coarse-loamy).

DRAINAGE AND SATURATED HYDRAULIC CONDUCTIVITY:
Drainage: Somewhat poorly drained
Surface runoff: Low
Saturated hydraulic conductivity: Moderately low
Flooding: rare or occasional
Depth to water table: 30 to 91 centimeters (1 to 3 feet)

USE AND VEGETATION: Most of the area cultivated.
The most common crops are corn, grain sorghum, and alfalfa.
A small acreage is in native grass and a few areas have scattered trees.

DISTRIBUTION AND EXTENT: Central, north-central, and southeastern Nebraska and adjoining areas of northern Kansas. LRR H Great Plains Winter Wheat and Range, MLRA 71, Central Nebraska Loess Hills, MLRA 72 Central High Tableland, MLRA 73, Rolling Plains and Breaks, MLRA 74 Central Kansas Sandstone Hills, MLRA 75 Central Loess Plains; LRR M Central Feed Grains and Livestock Region, MLRA 102C Loess Uplands, MLRA 106 Nebraska and Kansas Loess-Drift Hills; The Gibbon series is of moderate extent.

MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Denver, Colorado

SERIES ESTABLISHED: Douglas County, Nebraska, 1970.

REMARKS: Diagnostic horizons and other features recognized in this pedon are: Mollic epipedon: 0 to 28 centimeters (0 to 11 inches) (Ap and A horizon)
Aquic soil conditions: 46 to 200 centimeters (18 to 79 inches) (Cg1, Cg2 and Cg3 horizons).

Phases recognized include saline, saline-alkali, and overwash. These soils generally are not saturated at depths between 38 to 50 centimeters (15 to 20 inches) during the growing season. In the Saline phase, the Electrical Conductivity is 2 to 8 millimhos per centimeters and the Sodium Adsorption Ratio is 10 to 15 above 65 centimeters, decreasing with depth.

Keys to soil Taxonomy: Eleventh edition, 2010

10/17/05 JCR
Changed to semi-tab format, added metric conversions and changed from permeability to saturated hydraulic conductivity

7/27/2011 JLG
Add Additional Data, split out the Cg horizon in range of characteristics, and up-dated geographic setting data. Changed mean annual soil temperature from 9 to 11 degrees to 10 to 14 degrees. Changed episaturation to endosaturation based on the water table is not perched. Added depth to redox depletions. Added clay and sand content and particle control section. Separated AC and Cg horizons and added very fine sandy loam, fine sandy loam as textures to the Cg horizons based on textures of the type location and field data. In the Cg horizon changed clay content from 18 to 32 to 35 percent and changed sand content from 5 to 45 to 5 to 75 percent. We expanded range of mean annual temperature from 12 to 13 degrees and mean annual precipitation from 760 to 850 millimeters. Expanded frost free days from 170 days to 190 days. Updated differences of soils in Geographically Associated soils section. Added keys to soil taxonomy version. Changed precipitation values from centimeters to millimeters.

ADDITIONAL DATA: Additional laboratory data- National Soil Survey Laboratory, Lincoln, Nebraska pedons: 85NE163205

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National Cooperative Soil Survey
U.S.A.