LOCATION CHANGAS                 TX

Tentative Series
NAR/JAG/JAD
07/2012

CHANGAS SERIES

The Changas series consists of very deep, well drained soils that formed in gypsiferous clayey lacustrine deposits in the Presidio and Hueco Bolsons. Changas soils occur on erosional fan remnants. Slope ranges from 5 to 45 percent. The mean annual precipitation is about 10 inches and the mean annual air temperature is about 72 degrees F.

TAXONOMIC CLASS: Fine, smectitic, hyperthermic Leptic Haplogypsids

TYPICAL PEDON: Changas sandy clay loam in an area of map unit 111 Changas-Corazones complex, 1 to 30 percent slopes.

A--0 to 4 inches; yellowish brown (10YR 5/4) sandy clay loam, dark yellowish brown (10YR 4/4) moist; moderate fine and medium subangular blocky structure; hard, firm, very sticky, very plastic; violent effervescence; slightly alkaline; clear smooth boundary.

By1--4 to 15 inches; yellowish brown (10YR 5/4) clay, dark yellowish brown (10YR 4/4) moist; moderate fine and medium subangular blocky structure; hard, firm, very sticky, very plastic; 3 percent weakly cemented gypsum masses; violent effervescence; slightly alkaline; clear smooth boundary.

By2--15 to 25 inches; brown (10YR 4/3) clay, brown (10YR 4/3) moist; moderate fine and medium angular blocky structure; very hard, very firm, very sticky, very plastic; 10 percent fine weakly cemented gypsum masses; violent effervescence; slightly alkaline; clear smooth boundary.

By3--25 to 80 inches; pale brown (10YR 6/3) clay, brown (10YR 5/3) moist; moderate fine subangular blocky structure; hard, firm, very sticky, very plastic; 8 percent fine weakly cemented gypsum masses; violent effervescence; slightly alkaline.

TYPE LOCATION: Hudspeth County, TX; Neely Canyon, TX USGS topographic quadrangle; Latitude: 31 degrees, 5 minutes, 54.26 seconds North, Longitude: 105 degrees, 35 minutes, 21.30 seconds West. UTM Easting: 443804 meters, UTM Northing: 3440657 meters, UTM Zone 13.

RANGE IN CHARACTERISTICS:

Soil moisture: Ustic aridic soil moisture regime.

Mean annual soil temperature: 72 to 85 degrees F.

Depth to gypsic horizon: 0 to 7 inches

Particle-size control section (weighted average)
Clay content: 40 to 55 percent
Rock fragments: 0 to 20 percent gravel

A horizon
Hue: 5YR, 7.5YR, 10YR
Value: 4 to 6 dry, 4 to 5 moist
Chroma: 3 to 4, dry or moist
Texture: silty clay, clay, silty clay loam, sandy clay loam
Clay content: 25 to 50 percent
Calcium carbonate equivalent: 5 to 15 percent
Gypsum content: 1 to 5 percent
Salinity (EC): 0 to 2 dS/m
Sodicity (SAR): 0 to 10
Effervescence: strong or violent
Reaction: neutral to moderately alkaline

By and Byz horizons
Hue: 5YR, 7.5YR, 10YR
Value: 4 to 7 dry, 4 to 6 moist
Chroma: 2 to 4, dry or moist
Texture: silty clay, clay
Clay content: 40 to 60 percent
Calcium carbonate equivalent: 5 to 15 percent
Gypsum content: 2 to 15 percent
Salinity (EC): 0 to 8 dS/m
Sodicity (SAR): 0 to 25
Effervescence: strong or violent
Reaction: neutral to moderately alkaline

COMPETING SERIES: There are no competing series.

GEOGRAPHIC SETTING: Changas soils are on erosional fan remnants of the Presidio and Hueco Bolsons at elevations of 1,800 to 4,000 feet. These soils formed in gypsiferous clayey lacustrine deposits. Slopes range from 5 to 45 percent. Mean annual precipitation ranges from 10 to 13 inches. Most precipitation occurs as high intensity rain during afternoon thunderstorms from June to September. Mean annual air temperature ranges from 68 to 72 degrees F. The frost-free period is 240 to 280 days.

GEOGRAPHICALLY ASSOCIATED SOILS: These are the Corazones (TX), Melado (T-TX), Ojinaga (T-TX), and Pantera (TX) series. Corazones, Ojinaga, and Pantera soils contain more than 35 percent rock fragments in the particle-size control section. Corazones and Ojinaga soils occur on higher positions, and Pantera soils occur on lower drainageways. Melado soils do not have a gypsic horizon and occur on lower areas.

DRAINAGE AND PERMEABILITY: Well drained. Permeability is slow or very slow. Runoff is very high.

USE AND VEGETATION: Used for livestock grazing, wildlife habitat, and recreation. Hot Desert Shrub vegetative zone. Native vegetation consists of fourwing saltbush, mound saltbush, tubercled saltbush, tobosa, and alkali sacaton.

DISTRIBUTION AND EXTENT: LRR D. Southern Desertic Basin, Plains, and Mountains-MLRA 42. The series is of minor extent.

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

SERIES ESTABLISHED: Hudspeth County, Texas; Soil Survey of Hudspeth County, Texas (Main Part), 2012.

REMARKS: These soils were formerly included in the Vieja series. The series was separated based on landscape and parent material.

Diagnostic horizons and features recognized in this pedon are:

Particle-size control section - The zone from 10 to 40 inches (By horizons)

Ochric epipedon - the zone from 0 to 4 inches (A horizon)

Leptic feature - gypsic horizon within 7 inches of the soil surface

Gypsic horizon - the zone from 4 to 80 inches (By horizons)

Classified according to Soil Taxonomy, Second Edition, 1999; Keys to Soil Taxonomy, Eleventh Edition, 2010

Revised for the correlation of Hudspeth County, Texas (Main Part) and Culberson County, Texas (Main Part); July, 2012, NMS

ADDITIONAL DATA: Data from TAMU Soil Characterization Lab(S04TX377-004) is available for pedon S04-TX377-328.

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National Cooperative Soil Survey
U.S.A.