LOCATION GERRARD CO+MT WYEstablished Series
TAXONOMIC CLASS: Fine-loamy over sandy or sandy-skeletal, mixed, superactive, frigid Typic Endoaquolls
TYPICAL PEDON: Gerrard loam-grassland. (Colors are for dry soil unless otherwise noted.)
A1--0 to 5 inches; gray (10YR 5/1) loam, very dark gray (10YR 3/1) moist; strong fine granular structure; soft, very friable; 5 percent gravel; slightly alkaline (pH 7.4); clear smooth boundary. (4 to 8 inches thick)
A2--5 to 14 inches; gray (10YR 5/1) loam, very dark gray (10YR 3/1) moist; massive; common medium distinct mottles of brown (7.5YR 4/4) moist; weak fine subangular blocky structure parting to moderate medium granules; hard, very friable; neutral (pH 7.0); gradual wavy boundary. (3 to 15 inches thick)
2C--14 to 60 inches; very gravelly loamy sand; 40 percent gravel.
TYPE LOCATION: Rio Grande County, Colorado; approximately 2,600 feet south and 20 feet east of the NW corner of Sec. 25, T. 40 N., R. 5 E.
RANGE IN CHARACTERISTICS:
Mean annual soil temperature: 41 to 46 degrees F (5.0 to 7.8 degrees C)
Mean summer soil temperature: 58 to 63 degrees F (15.0 to 17.2 degrees C)
Depth to a seasonal water table and endosaturation is 10 to 20 inches (25 to 51 centimeters).
Depth to sandy or sandy-skeletal substratum: 12 to 20 inches (30 to 51 centimeters)
Mottles: distinct to prominent
Particle-size control section upper part (weighted average):
Clay content: 18 to 35 percent
Sand content: 10 to 35 percent fine or coarser
Rock fragments: 0 to 35 percent, mainly 1 to 10 inches (8 to 25 centimeters)
in diameter
In some pedons with a few discontinuous subhorizons, hues redder than 7.5YR occupy less than half the thickness of the control section.
A or Ag horizon(s):
Hue: 5Y to 7.5YR
Value: 4 or 5 dry, 2 or 3 moist
Chroma: of 1 to 2
Texture: loam, sandy loam and clay loam (A2)
2C or 2Cg horizon(s):
Hue: 5Y to 7.5YR (with variegated colors)
Value: 4 to 6 dry, 3 or 4 moist
Chroma: 2 to 4
Texture: very gravelly loamy sand, loamy sand, loamy fine sand, sand, gravelly to extremely gravelly sand, gravelly to extremely gravelly loamy sand
Some pedons have 3g horizons
COMPETING SERIES: These are the
Blossberg and
Vastine series.
Blossberg soils have a cambic horizon
Vastine soils have contrasting sand and gravel layers at depths of 20 to 40 inches (51 to 102 centimeters).
GEOGRAPHIC SETTING:
Parent material: soils formed in thin, noncalcareous, moderately fine textured alluvium overlying sand and gravel substratums derived from igneous, metamorphic and sedimentary rock.
Landform: stream terraces, flood plains and alluvial fans
Slopes: 0 to 6 percent
Elevation: 7,500 to 8,000 feet (2,286 to 2,438 meters)
Mean annual air temperature: 40 to 46 degrees F. (5.0 to 7.8 degrees C)
Mean summer temperature: 58 to 63 degrees F (14.4 to 17.2 degrees C)
Mean annual precipitation: 6 to 8 inches (152 to 203 millimeters)
Precipitation pattern: The soil moisture control section is affected by peak precipitation in late summer and early fall. The soil is driest from November to March. The soil has the potential to be moist from April to October.
Frost-free period: 85 to 100 days
GEOGRAPHICALLY ASSOCIATED SOILS: These are the
Acasco soils and the competing
Vastine soils.
Acasco soils have more than 35 percent clay in the upper part of the control section and have sand and gravel below a depth of 20 inches (51 to centimeters).
Vastine soils have contrasting sand and gravel layers at depths of 20 to 40 inches (51 to 102 centimeters).
DRAINAGE AND PERMEABILITY: Poorly drained; slow runoff; moderately slow permeability. These soils have a fluctuating water table that is at or near the surface during some season in most years.
USE AND VEGETATION: These soils are used as native pastureland or are used for irrigated pasture or irrigated hay crops. Native plants are sedges, rushes, and willows.
DISTRIBUTION AND EXTENT: San Luis Valley Area of south-central Colorado; LRR E, MLRA 51. The series is of moderate extent.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Bozeman, Montana
SERIES ESTABLISHED: Rio Grande County, Colorado, 1972.
REMARKS:
Diagnostic horizons and features recognized in this pedon are:
This soil is saturated from 10 to 60 inches (25 to 152 centimeters).
Mollic epipedon: 0 to 15 inches (0 to 38 centimeters) (A, Ag horizons).
Lithologic discontinuity: 12 to 60 inches (30 to 152 centimeters) (2Cg1, 2Cg2, 2Cg3 horizons)
Last updated by the state 3/99
Taxonomy version: Tenth Edition, 20006