LOCATION CORLETT                 CO

Established Series
Rev.GB/WRM/TWH
01/2011

CORLETT SERIES

The Corlett series consists of very deep, somewhat excessively drained soils that formed in sandy eolian deposits derived from igneous and metamorphic rock. Corlett soils are on playa dunes and dunes. Slopes range from 0 to 25 percent. The mean annual precipitation is about 7 inches and the mean annual temperature is about 41 degrees F.

TAXONOMIC CLASS: Mixed, frigid Typic Torripsamments

TYPICAL PEDON: Corlett sand, grassland. (Colors are for dry soil unless otherwise noted.)

A--0 to 8 inches; light brownish gray (10YR 6/2) sand, dark grayish brown (10YR 4/2) moist; single grain; loose; calcareous; 3 percent calcium carbonate equivalent; very strongly alkaline (pH 9.8); gradual smooth boundary. (4 to 10 inches thick)

C1--8 to 24 inches; light brownish gray (10YR 6/2) sand, brown (10YR 5/3) moist; single grain; loose; slightly calcareous; 5 percent calcium carbonate equivalent; very strongly alkaline (pH 9.8); gradual smooth boundary.

C2--24 to 36 inches; light brownish gray (10YR 6/2) sand, grayish brown (10YR 5/2) moist; single grain; loose; slightly calcareous; 3 percent calcium carbonate equivalent; very strongly alkaline (pH 10.2); gradual smooth boundary.

C3--36 to 60 inches; pale brown (10YR 6/3) sand, brown (10YR 5/3) moist; single grain; loose; slightly calcareous; 4 percent calcium carbonate equivalent; very strongly alkaline (pH 10.0).

TYPE LOCATION: Alamosa County, Colorado; about 8 miles east of Mosca; about 300 feet north and 2,340 feet east of the southwest corner of sec. 36, T. 40 N., R. 11 E.

RANGE IN CHARACTERISTICS:
Soil moisture: The soil moisture control section is usually dry but is intermitttently moist in winter, spring, and late summer; typic aridic moisture regime.
Mean annual soil temperature: 42 to 46 degrees F. (5.6 to 7.4 degrees C.)
Mean summer soil temperature: 59 to 64 degrees F. (14.5 to 17.8 degrees C.)
Depth to free carbonates: 0 to 10 inches (0 to 25 cm)
Depth to endosaturation: 42 to 72 inches (100 to 183 cm) in April through October (see Remarks below)
Sand and silt fractions contain 5 to 20 percent or more dark colored ferromagnesian rich minerals and fragments of basalt.

Particle-size control section (weighted average):
Noncarbonate clay content: 0 to 5 percent

A horizon:
Hue: 7.5YR to 2.5Y
Value: 5 to 7 dry, 3 to 6 moist
Chroma: 1 to 4
Texture: sand, fine sand, loamy fine sand
Clay content: 0 to 6 percent
Calcium carbonate equivalent: 0 to 10 percent
SAR: 0 to 10
Reaction: strongly alkaline or very strongly alkaline

C horizons:
Hue: 7.5YR to 2.5Y
Value: 5 to 7 dry, 3 to 6 moist
Chroma: 2 or 3
Texture: loamy sand, sand, fine sand
Clay content: 0 to 5 percent
Calcium carbonate equivalent: 1 to 10 percent
Exchangeable sodium content: 15 to 75 percent
SAR: 15 to 30
Reaction: strongly alkaline or very strongly alkaline

COMPETING SERIES: These are the (T) Bodorumpe, Cotopaxi, Kandaly, and Space City series. Bodorumpe soils have a paralithic contact above a depth of 40 inches. Cotopaxi soils are noncalcareous to depths of more than 40 inches and have less than 15 percent exchangeable sodium. Kandaly soils have an exchangeable sodium percentage less than 15 percent and are slightly to moderately alkaline. Space City soils are noncalcareous to depths of more than 10 inches; have horizons of secondary carbonate accumulation located in the lower part of the solum, and have less than 15 percent exchangeable sodium.

GEOGRAPHIC SETTING: Corlett soils are on dunes and playa dunes on the basin floor of the San Luis Valley area. Slope ranges from 0 to 25 percent. Some of the dunes have a salt crust on the surface. The soil formed in sandy eolian deposits derived from igneous and metamorphic rock. The average annual precipitation is 6 to 9 inches, with peak periods of precipitation in the spring and early summer. Mean annual temperature ranges from 40 to 44 degrees F.

GEOGRAPHICALLY ASSOCIATED SOILS: These are the Hooper and Littlebear soils. Hooper soils have fine textured natric horizons. Littlebear soils are moderately coarse textured in the upper part of the control section.

DRAINAGE AND PERMEABILITY: Somewhat excessively drained, rapid permeability.

USE AND VEGETATION: These soils are used principally as native pastureland. Native vegetation is mainly greasewood, rabbitbrush, saltgrass, and alkali sacaton.

DISTRIBUTION AND EXTENT: The San Luis Valley 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: Alamosa County, Colorado, 1974. This series was originally proposed in 1945. The name is from a ranch in Alamosa County.

REMARKS:
Diagnostic horizons and features recognized in this pedon are:
Series control section: The zone from 0 to 60 inches.
Particle-size control section: The zone from 10 to 40 inches (part of the C1, the C2, and part of the C3 horizons)
Ochric epipedon: From 0 to 8 inches (A horizon)
Although the C1 horizon has 5 percent carbonate, it is not recognized as a calcic horizon because it does not have evidence of secondary accumulations.

The 01/2011 revision updates the typical pedon description to match the description used as the typical pedon for the Alamosa Area published soil survey. This revision also changes the drainage class to somewhat excessively drained. This series was originally defined with a fluctuating water table at 42 to 72 inches. Recent work is indicating that a water table this shallow is uncommon. The conversion from surface to sprinkler irrigation may be contributing to this. Moreover, on the upper slopes of dunes with high relief, it seems unlikely saturation could persist at these depths. The 01/2011 revision provisionally retains the original water table criterion, but it is likely the central concept of this series will be revised to have no saturation within the series control section (150 cm).


Taxonomy version: Eleventh Edition, 2010.

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National Cooperative Soil Survey
U.S.A.