LOCATION REDUFF TX

Established Series
Rev. LEL/JLR/ACT
10/2012

REDUFF SERIES

The Reduff series consists of very shallow and shallow, well drained, moderately slowly permeable soils over very slowly permeable tuffaceous bedrock. These hilly to very steep soils formed in residuum weathered from red tuffaceous strata of the Duff and Pruett Formations. They are on erosional uplands, hills, and scarps. Slopes range from 10 to 90 percent. The mean annual precipitation is about 12 inches and the mean annual air temperature is about 64 degrees F.

TAXONOMIC CLASS: Loamy-skeletal, mixed, superactive, nonacid, thermic Lithic Ustic Torriorthents

TYPICAL PEDON: Reduff very gravelly loam - rangeland. (Colors are for dry soil unless otherwise stated.)

A--0 to 4 inches; reddish brown (5YR 5/3) very gravelly loam, reddish brown (5YR 4/3) moist; weak fine subangular blocky parting to weak fine granular structure; many very fine and fine roots; 30 percent light reddish brown (2.5YR 6/4) angular tuff gravel 2 to 20 mm in diameter and 20 percent light reddish brown (2.5YR 6/4) subangular tuff gravel 20 to 75 mm in diameter; very slightly effervescent; moderately alkaline; abrupt smooth boundary. (3 to 9 inches thick)

C--4 to 15 inches; reddish brown (5YR 5/3) extremely gravelly loam, reddish brown (5YR 4/3) moist; weak fine granular structure; common very fine, fine and medium roots in cracks; few distinct discontinuous white (10YR 8/1) calcium carbonate coatings on rock fragments; 25 percent angular tuff gravel 2 to 20 mm in diameter, 40 percent angular tuff gravel 20 to 75 mm in diameter, and 15 percent angular tuff stones; noneffervescent; slightly alkaline; abrupt smooth boundary. (0 to 12 inches thick)

R--15 to 60 inches; light reddish brown (2.5YR 6/4) weathered bedrock, reddish brown (2.5YR 4/4) moist; strongly cemented; noneffervescent.

TYPE LOCATION: Brewster County, Texas; from the junction of U.S. Highway 90 and Texas Highway 118 in Alpine; 32.3 miles south on Texas Highway 118 to 02 Ranch gate, 11.6 miles southwest on ranch road to 02 Ranch Headquarters, 6.1 miles north-northwest and northwest on ranch road to cattle guard, 2.1 miles northeast on ranch road to junction, 0.6 miles north-northeast on ranch road, 0.1 mile north-northeast on old seismic trail, 500 feet east in rangeland. Paradise Draw USGS 7.5 minute topographic quadrangle. Latitude: 29 degrees, 56 minutes, 13 seconds North; Longitude: 103 degrees, 46 minutes, 49 seconds West; NAD 1927.

RANGE IN CHARACTERISTICS:

Soil moisture - Intermittently moist in the soil moisture control section during July-September. The soil is moist for less than 90 cumulative days during the growing season in the control section. Ustic aridic soil moisture regime.

Depth to a lithic contact ranges from 4 to 20 inches

Clay content control section: 20 to 35 percent

Rock fragments: 35 to 80 percent in the control section

Reaction: neutral to moderately alkaline

Organic carbon content: greater than 2 percent

A horizon
Hue: 2.5YR, 5YR
Value: 4 to 6, dry or moist
Chroma: 2 to 4, dry or moist
Texture: loam, clay loam
Rock fragments: 35 to 60 percent
Effervescence: noneffervescent to slightly effervescent

C horizon (where present)
Hue: 2.5YR, 5YR
Value: 4 to 6, dry or moist
Chroma: 2 to 4, dry or moist
Texture: loam, clay loam
Rock fragments: 35 to 80 percent
Effervescence: noneffervescent

R layer
It is noncalcareous tuff bedrock of the Duff and Pruett Formations

COMPETING SERIES: These are the Coyanosa (TX), Lampshire (AZ) and Lingua (TX) series. Coyanosa and Lampshire soils average less than 18 percent clay in the control section. Lingua soils are include hues of 10YR and 7.5YR and have less than 2 percent organic carbon.

GEOGRAPHIC SETTING: Reduff soils are on erosional uplands, hills, mountain flanks and tops and scarps. Slopes range from 10 to 70 percent. These soils formed in residuum weathered from red tuff strata of the Duff and Pruett Formations, and also occur on chert and basalt. Mean annual precipitation ranges from 10 to 15 inches, with most occurring from July through September. Mean annual air temperature ranges from 60 to 68 degrees F. Frost free period is 170 to 275 days. Elevation ranges from 3,500 to 5,500 feet.

GEOGRAPHICALLY ASSOCIATED SOILS: These are the Borunda, Gemelo, and Holguin soils. Borunda soils lower in the landscape on convex erosional uplands and are moderately deep to weathered tuff bedrock, have calcic and gypsic horizons, and contain less than 35 percent rock fragments in the control section. Gemelo soils are very deep, have cambic horizons, and contain less than 35 percent rock fragments in the control section. They are on alluvial fan aprons. Holguin soils are underlain with cemented conglomerate bedrock on ridge caps higher in the landscape.

DRAINAGE AND PERMEABILITY: Well drained. Permeability is moderately slow in the surface layer and very slow in the tuffaceous bedrock. Runoff is high on slopes of 10 to 20 percent and very high on 20 to 70 percent.

USE AND VEGETATION: This soil is used as livestock grazing and wildlife habitat. Woody species consist of creosotebush, whitethorn acacia, feather dalea, skeletonleaf goldeneye, cholla, mariola, javelinabush, prickly pear, and range ratany. Grasses include black grama, sideoats grama, cane bluestem, green sprangletop and tanglehead.

DISTRIBUTION AND EXTENT: West Texas. MLRA 42. The series is moderately extensive.

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

SERIES ESTABLISHED: Brewster County, Texas, 1997. The name is coined from a tuffaceous geological formation.

REMARKS: Diagnostic horizons and features recognized in this pedon are:

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

Lithic contact - the boundary at 15 inches (R horizon)

Ustic feature - the soil has an aridic moisture regime that borders the ustic moisture regime

Entisol feature - the absence of diagnostic subsurface horizons

Superactive cation activity class - CEC to percent clay ratio is 0.60 or greater. This is assumed from the abundant zeolitic minerals in the Duff and Pruett Tuffs.

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

Update and revisions for the recorrelation of Brewster County, Texas, Main Part, 2/8/2008, CEM.

Revised for the correlation of Presidio County, Texas ; Oct, 2012, WWJ

National Cooperative Soil Survey
U.S.A.