LOCATION BENKELMAN          NE
Established Series
Rev. JRW/DH/PRF
04/2000

BENKELMAN SERIES


The Benkelman series consists of very deep, well drained soils formed in calcareous, loamy alluvial sediments on stream terraces and alluvial fans. Permeability is moderate. Slopes range from 0 to 2 percent. The mean annual precipitation is about 17 inches, and mean annual air temperature is about 52 degrees F at the type location.

TAXONOMIC CLASS: Coarse-silty, mixed, superactive, calcareous, mesic Aridic Ustorthents

TYPICAL PEDON: Benkelman very fine sandy loam with a slope of 1 percent in a cultivated field. (Colors are for dry soil unless otherwise stated.)

Ap--0 to 4 inches; pale brown (10YR 6/3) very fine sandy loam; brown (10YR 5/3) moist; weak fine granular structure; soft, very friable; few fine roots; 1 percent calcium carbonate; slightly effervescent; moderately alkaline; abrupt smooth boundary. (2 to 10 inches thick)

AC--4 to 11 inches; light brownish gray (10YR 6/2) very fine sandy loam; grayish brown (10YR 5/2) moist; weak medium subangular blocky structure; soft, very friable; few, fine and very fine roots; 2 percent calcium carbonate; strongly effervescent; moderately alkaline; clear smooth boundary. (0 to 10 inches thick)

C1--11 to 22 inches; pale brown (10YR 6/3) very fine sandy loam; brown (10YR 5/3) moist; massive; soft, very friable; 3 percent calcium carbonate; strongly effervescent; strongly alkaline; clear smooth boundary.

C2--22 to 34 inches; very pale brown (10YR 7/3) very fine sandy loam; pale brown (10YR 6/3) moist; massive; soft, very friable; few, fine bedding planes of loamy fine sand; 2 percent calcium carbonate; strongly effervescent; strongly alkaline; diffuse wavy boundary.

C3--34 to 46 inches; very pale brown (10YR 7/3) very fine sandy loam; pale brown (10YR 6/3) moist; massive; soft, very friable; 3 percent calcium carbonate; strongly effervescent; strongly alkaline; diffuse wavy boundary.

C4--46 to 80 inches; very pale brown (10YR 7/3) very fine sandy loam; pale brown (10YR 6/3) moist; massive; soft, very friable; 2 percent calcium carbonate; strongly effervescent; strongly alkaline.

TYPE LOCATION: Dundy County, Nebraska; about 3 miles north and 4 miles east of Benkelman, Nebraska; 800 feet north and 1400 feet east of the southwest corner of section 36, T.2 N., R.37 W. Max topographic quadrangle; latitude 40 degrees, 5 minutes, 33 seconds North and longitude 101 degrees, 27 minutes West.

RANGE IN CHARACTERISTICS:
Depth to carbonates: 0 to 10 inches, typically at the surface
Particle-size control section calcium carbonate equivalent: 1 to 5 percent
Series control section particle-size distribution: irregular due to the alluvial deposition of the parent material, thin bedding planes are common
Series control section sand: typically more than 80 percent, by weighted average, of the total sand consists of very fine sand

A horizon:
Hue: 10YR
Value: 4 to 6 dry, 3 to 5 moist
Chroma 2 to 3
Reaction: slightly to moderately alkaline
Texture: very fine sandy loam, loam
Comments: Horizons having value of less than 5.5 dry and 3.5 moist are less than 6 inches thick.

AC horizon:
Hue: 10YR
Value: 5 to 6 dry, 4 to 5 moist
Chroma: 2 to 3
Reaction: slightly to moderately alkaline
Texture: very fine sandy loam, loam
Comments: Some pedons do not have an AC horizon.

C horizon:
Hue: 10YR to 2.5Y
Value: 5 to 7 dry, 4 to 6 moist
Chroma: 2 to 4
Reaction: moderately to strongly alkaline
Texture: very fine sandy loam, loam

COMPETING SERIES:
Nevee: depth to bedrock ranges from 40 to 60 inches or more, formed in silty alluvium weathered from reddish colored silty shale, siltstone or sandstone
Sulco: have more uniform particle size distribution throughout the series control section, have carbonate accumulations as masses in the series control section, have calcium carbonate equivalent that ranges from 5 to 15 percent in the particle size control section on higher landscapes

GEOGRAPHIC SETTING:
Landscape: river valleys
Landform: stream terraces and alluvial fans
Slopes: 0 to 2 percent
Elevation: 2500 to 4500 feet
Parent material: calcareous, loamy alluvial sediments derived from loess
Mean annual air temperature: 47 to 54 degrees F
Mean annual precipitation: 14 to 18 inches
Frost-free period: 120 to 150 days

GEOGRAPHICALLY ASSOCIATED SOILS:
Bridget: have a mollic epipedon on similar landforms
Craft: are highly stratified on flood plains
Otero: are coarse-loamy on similar landforms

DRAINAGE AND PERMEABILITY: Well drained. Runoff is low. Permeability is moderate.

USE AND VEGETATION: The Benkelman soils are used mostly for cropland. A large acreage is irrigated. Alfalfa and corn are the main crops grown.

DISTRIBUTION AND EXTENT: Western Nebraska and possibly northwest Kansas, northeast Colorado and southeast Wyoming.

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

SERIES ESTABLISHED: Dundy County, Nebraska, 1995.

REMARKS: The Benkelman soils were previously mapped with the Bridgeport soils. Diagnostic horizons and features recognized in this pedon are: ochric epipedon - the zone from the surface of the soil to a depth of 4 inches (A horizon).

ADDITIONAL DATA: Pedon S89NE-057-100 sampled for National Soil Survey Laboratory.

OTHER DATA:
T: 5
K: .37
WEG: 3
WEI: 86


National Cooperative Soil Survey
U.S.A.