LOCATION MCCOOK NE+CO KS WYEstablished Series
TAXONOMIC CLASS: Coarse-silty, mixed, superactive, mesic Fluventic Haplustolls
TYPICAL PEDON: McCook silt loam with a slope of less than 1 percent in a cultivated field. (Colors are for dry soil unless otherwise stated.)
Ap--0 to 15 centimeters (0 to 6 inches); grayish brown (10YR 5/2) silt loam, very dark grayish brown (10YR 3/2) moist; weak fine granular structure; soft, very friable; slight effervescence; slightly alkaline; abrupt smooth boundary.
A--15 to 38 centimeters (6 to 15 inches); grayish brown (10YR 5/2) silt loam, very dark grayish brown (10YR 3/2) moist; weak coarse prismatic structure; soft, very friable; slight effervescence; slightly alkaline; abrupt smooth boundary. (Combined thickness of A horizons is 25 to 51 centimeters (10 to 20 inches).)
AC--38 to 79 centimeters (15 to 31 inches); light brownish gray (10YR 6/2) silt loam, dark grayish brown (10YR 4/2) moist; weak coarse prismatic structure parting to weak medium and fine granular; soft, very friable; strong effervescence; moderately alkaline; clear smooth boundary. (15 to 46 centimeters (6 to 18 inches) thick)
C1--79 to 97 centimeters (31 to 38 inches); light brownish gray (10YR 6/2) silt loam, grayish brown (10YR 5/2) moist; massive; soft, very friable; fine stratification in upper part; strong effervescence; moderately alkaline; gradual smooth boundary. (13 to 51 centimeters (5 to 20 inches) thick)
C2--97 to 203 centimeters (38 to 80 inches); light gray (10YR 7/2) very fine sandy loam, grayish brown (10YR 5/2) moist; massive; soft, very friable; strong effervescence; moderately alkaline.
TYPE LOCATION:Red Willow County, Nebraska; 1 mile south and 3 miles west of McCook, Nebraska; 76 meters (250 feet) east and 30 meters (100 feet) south of the center, sec. 34, T. 3 N., R. 30 W.
RANGE IN CHARACTERISTICS:
Mollic epipedon: 25 to 51 centimeters (10 to 20 inches)
Depth to free carbonates: less than 25 centimeters (10 inches) and most pedons are calcareous at or near the surface
Particle size control section (weighted average):
Clay content: 10 to 18 percent
A horizon:
Hue: 10YR
Value: 4 or 5 and 2 or 3 moist
Chroma: 1 or 2
Texture: silt loam, very fine sandy loam, loam, fine sandy loam, silty clay loam, and clay loam
Reaction: slightly or moderately alkaline
AC and C horizons:
Hue: 10YR
Value: 5 through 7, 4 through 6 moist
Chroma: 2 or 3 and strata with chroma of 1
Texture: silt loam or very fine sandy loam but also include loam. Buried soils or thin strata of slightly coarser or finer textured material are in the C horizon in most pedons. Sandy loam and coarser textures are below a depth of 40 inches in some areas.
Reaction: slightly or moderately alkaline
COMPETING SERIES: The
Ralton series in the same family.
Ralton soils are moderately well drained and have endo saturation at depths of 1 to 2 meters (3 to 6 feet).
GEOGRAPHIC SETTING:
Parent material: Stratified calcareous alluvium
Landform: flood plains
Slopes: 0 to 3 percent
Mean annual precipitation: 36 to 61 centimeters (14 to 24 inches)
Mean annual temperature: 8 to 12 degrees C (46 to 54 degrees F)
GEOGRAPHICALLY ASSOCIATED SOILS: These are the
Cozad,
Eltree,
Gibbon,
Glenberg,
Haverson,
Hord,
Inavale,
Las,
Leshara,
Munjor,
Roxbury, and
Wann soils.
Cozad, Eltree, Hord, and Munjor soils are higher in the landscape, and Roxbury soils are at the same level.
Gibbon soils are fine-silty, are on lower elevations, and are somewhat poorly drained.
Glenberg soils are coarse-loamy and are higher in the landscape.
Haverson soils are fine-loamy and are lower in the landscape.
Inavale soils are sandy and are lower in the landscape.
Las and Leshara soils contain more clay, are wetter, and are lower in the landscape.
Wann soils are coarse-loamy, are somewhat poorly drained, and are generally lower in the landscape.
DRAINAGE AND SATURATED HYDRAULIC CONDUCTIVITY:
Drainage: well drained
Surface runoff: low
Saturated hydraulic conductivity: moderately high
Flooding: rarely or occasionally, brief duration
Depth to the seasonal high water table: below 2 meters (6 feet)
USE AND VEGETATION: Most areas are cultivated and irrigated.
Major crops are corn, grain sorghum, alfalfa, and winter wheat.
Only a small acreage is still in native vegetation.
DISTRIBUTION AND EXTENT: South-central and western Nebraska, north-central and western Kansas, eastern Colorado, and possibly eastern Wyoming. LRR G and H; MLRA 64, 67, 72, 73, 74, 75. The series is of large extent.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Denver, Colorado
SERIES ESTABLISHED: Red Willow County, Nebraska, 1965.
REMARKS: Diagnostic horizons and other features recognized in this pedon are:
Mollic epipedon: 0 to 38 centimeters (0 to 15 inches) (Ap and A horizon)
Irregular decrease in organic carbon: 25 to 125 cm (10 to 49 inches)
Moisture regime: ustic
08/2003 WAW Added CEC activity class, updated competing series, revised to semi-tabular format.
11/2005 JCR LM
Updated saturated hydraulic conductivity and added metric conversion.
Phases of McCook soils recognized to date are commonly flooded, rarely flooded, overwash, alkali, wet and sandy substratum.
ADDITIONAL DATA: Physical and chemical data on the McCook typical pedon are available from the National Soil Survey Laboratory (sample numbers 71L915-71L917).