LOCATION TENGALLON               CO

Established Series
Rev. DKR/CES/WWJ
11/2022

TENGALLON SERIES

The Tengallon series consists of moderately deep, well drained soils that formed in residuum derived from Mancos Shale. Tengallon soils are on dissected pediments, plains and hills. Slopes range from 3 to 12 percent. Mean annual precipitation is about 8 inches and the mean annual temperature is about 54 degrees F.

TAXONOMIC CLASS: Fine-loamy, gypsic, mesic Typic Calcigypsids

TYPICAL PEDON: Tengallon sandy clay loam, on a south facing, 3 percent slope in rangeland at an elevation of 5,300 feet. (Colors are for dry soil unless otherwise noted.) When described on November 14, 1997 the soil was dry.

A--0 to 3 inches; light yellowish brown (10YR 6/4) sandy clay loam, dark yellowish brown (10YR 4/4) moist; strong very fine granular structure; soft, very friable, slightly sticky and nonplastic; common very fine and fine roots throughout; 13 percent calcium carbonate; violently effervescent; moderately alkaline (pH 8.3); abrupt smooth boundary. (1 to 5 inches thick)

Bk--3 to 9 inches; light brownish gray (10YR 6/2) clay loam, yellowish brown (10YR 5/4) moist; moderate thick platy structure; moderately hard, friable, moderately sticky and moderately plastic; common fine and medium roots throughout; common fine irregular calcium carbonate masses; 17 percent calcium carbonate; violently effervescent; moderately alkaline (pH 8.2); abrupt smooth boundary. (6 to 14 inches thick)

By1--9 to 17 inches; very pale brown (10YR 7/3) gypsiferous loam, light olive brown (2.5Y 5/4) moist; massive; soft, very friable, slightly sticky and nonplastic; common very fine and fine roots throughout; common fine gypsum crystals, 26 percent gypsum; 11 percent calcium carbonate; 5 percent parachanners; violently effervescent; moderately alkaline (pH 8.0); clear wavy boundary. (12 to 25 inches thick By horizons)

By2--17 to 28 inches; very pale brown (10YR 7/4) gypsiferous loam, light olive brown (2.5Y 5/4) moist; massive; soft, very friable, slightly sticky and slightly plastic; few very fine roots matted around shale fragments and between peds; few very fine discontinuous tubular pores; common fine irregular masses of gypsum between peds, 22 percent gypsum; 21 percent calcium carbonate; 10 percent parachanners; violently effervescent; moderately alkaline (pH 8.0); gradual smooth boundary.

Cr--28 to 46 inches; soft Mancos Shale.

TYPE LOCATION: Montezuma County, Colorado; about 8 miles southwest of Towaoc; located in an unsectionalized area, Mariano Wash West USGS quad; lat. 37 degrees 7 minutes 54 seconds N. and long. 108 degrees 53 minutes 41 seconds W., NAD 27

RANGE IN CHARACTERISTICS:

Soil moisture: The soil moisture control section is Typic aridic.

Mean annual soil temperature: 54 to 58 degrees F
Depth to paralithic contact: 20 to 40 inches
Depth to gypsic horizon: 4 to 13 inches

Particle-size control section (weighted average):
Clay content: 18 to 35 percent
Rock fragments: 0 to 5 percent

A horizon:
Hue: 7.5YR or 10YR
Value: 5 to 7, (4 to 6 moist)
Chroma: 3 or 4
Texture: sandy clay loam
Clay content: 20 to 30 percent
Rock fragments: 0 to 15, mainly gravel
Calcium carbonate equivalent: 1 to 15 percent
EC (mmhos/cm): 0 to 4
Gypsum: 0 to 5 percent
SAR: 0 to 3
Reaction: moderately alkaline

Bk horizon:
Hue: 7.5YR to 10YR
Value: 6 or 7, (5 or 6 moist)
Chroma: 2 to 4
Texture: silty clay loam, loam, clay loam
Clay content: 18 to 35 percent
Rock fragments: 0 to 2 percent
Pararock fragments: 0 to 15 percent
Calcium carbonate equivalent: 15 to 35 percent
EC (mmhos/cm): 0 to 4
Gypsum: 0 to 5 percent
SAR: 0 to 3
Reaction: moderately alkaline

By horizon:
Hue: 10YR or 2.5Y
Value: 6 or 7, (5 or 6 moist)
Chroma: 3 or 4
Texture: gypsiferous loam, gypsiferous silt loam, or gypsiferous silty clay loam
Clay content: 20 to 35 percent
Rock fragments: 0 to 2 percent
Pararock fragments: 0 to 50 percent shale fragments
Calcium carbonate equivalent: 2 to 25 percent
EC (mmhos/cm): 2 to 8
Gypsum: 15 to 35 percent
SAR: 0 to 3
Reaction: moderately alkaline

COMPETING SERIES: There are no competing series.

GEOGRAPHIC SETTING:
Parent material: residuum derived from Mancos Shale (Many areas have some eolian influence in the surface layers)
Landform: dissected pediments, plains and hills
Slopes: 3 to 12 percent
Elevation: 4,700 to 5,700 feet
Mean annual temperature: 52 to 56 degrees F
Mean annual precipitation: 7 to 10 inches
Precipitation pattern: Uniform with slight dip in May and June and slight increase in July and August.
Frost-free period: 135 to 160 days.

GEOGRAPHICALLY ASSOCIATED SOILS: These are the Persayo, Juanalo, and Chimrock series. The Persayo soils are shallow and are on hills. The Juanalo soils are shallow and are on edges of mesas. The Chimrock soils are very deep and are in drainageways.

DRAINAGE AND PERMEABILITY: Well drained, medium to high runoff, moderate permeability.

USE AND VEGETATION: Rangeland. Native vegetation is alkali sacaton, galleta and shadscale.

DISTRIBUTION AND EXTENT: Southwest Colorado; MLRA 35; small extent.

MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Phoenix, Arizona.

SERIES ESTABLISHED: Montezuma County, Colorado, Ute Mountain Area, Colorado and New Mexico, 2005.

REMARKS:
Diagnostic horizons and features recognized in this pedon are:
Series control section: The zone from 0 to 38 inches.
Particle-size control section: The zone from 10 to 28 inches. (By1, By2 horizons)
Ochric epipedon: The zone from 0 to 3 inches. (A horizons)
Calcic horizon: The zone from 3 to 9 inches. (Bk horizons)
Gypsic horizon: The zone from 9 to 28 inches. (By1, By2 horizons)
Paralithic contact: The contact with shale bedrock at 28 inches. (Cr horizons)

ADDITIONAL DATA: National Soil Survey Laboratory sample S99CO-083-07

Classified according to Keys to Soil Taxonomy Ninth Edition, 2003

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National Cooperative Soil Survey
U.S.A.