LOCATION BUTCHERKNIFE TX

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

BUTCHERKNIFE SERIES

The Butcherknife series consists of deep, well drained, slowly permeable soils on broad alluvial flats of late-Pleistocene age. These nearly level soils formed in clayey residuum and alluvium derived from tuffs of the Duff and Pruett Formations. Slopes range from 0 to 3 percent.

TAXONOMIC CLASS: Fine, mixed, superactive, thermic Ustic Calcigypsids

TYPICAL PEDON: Butcherknife silty clay loam - rangeland. (Colors are for dry soil unless otherwise stated.)

A--0 to 4 inches; brown (7.5YR 5/3) silty clay loam, brown (7.5YR 4/3) moist; moderate fine and medium subangular blocky parting to moderate very fine and fine granular structure; thin platy structure in upper 1 inch; hard, firm, moderately sticky and moderately plastic; common fine roots throughout; 14 percent calcium carbonate equivalent; nonsaline; strongly effervescent; moderately alkaline; clear smooth boundary (3 to 6 inches thick).

Bw1--4 to 12 inches; brown (7.5YR 5/3) clay, brown (7.5YR 4/3) moist; weak coarse prismatic parting to moderate medium and coarse angular blocky structure; very hard, very firm, very sticky and very plastic; common fine roots throughout; 16 percent calcium carbonate equivalent; slightly saline; violently effervescent; moderately alkaline; clear smooth boundary (8 to 14 inches thick).

Bw2--12 to 22 inches; brown (7.5YR 5/3) clay, brown (7.5YR 4/3) moist; weak coarse prismatic structure parting to moderate medium and coarse angular blocky; very hard, very firm, very sticky and very plastic; common very fine and fine roots throughout; many distinct continuous pressure faces on surfaces of peds; 14 percent calcium carbonate equivalent; moderately saline; violently effervescent; moderately alkaline; clear smooth boundary (9 to 14 inches thick).

Bkyz--22 to 30 inches; brown (7.5YR 5/3) clay, brown (7.5YR 4/3) moist; weak coarse subangular blocky parting to moderate medium subangular blocky structure; very hard, very firm, very sticky and very plastic; few very fine roots throughout; common fine and medium irregular masses of calcium carbonate, gypsum, and other salts throughout and between peds; 10 percent calcium carbonate equivalent; moderately saline; 25 percent gypsum; 30 percent tuff fragments that slake in water; violently effervescent; moderately alkaline; clear smooth boundary (5 to 21 inches).

BCkyz1--30 to 37 inches; pinkish gray (7.5YR 6/2) clay loam, brown (7.5YR 4/2) moist; weak medium and coarse subangular blocky structure; hard, firm, moderately sticky and moderately plastic; few very fine roots throughout; few prominent continuous very pale brown (10YR 8/2) coatings of calcium carbonate on surfaces of peds; common fine and medium irregular masses of calcium carbonate, gypsum, and other salts throughout and common fine and medium threads of soft calcium carbonate, gypsum, and other salts between peds; 27 percent calcium carbonate equivalent; moderately saline; 20 percent gypsum; 60 percent tuff fragments that slake in water; violently effervescent; moderately alkaline; clear smooth boundary (7 to 15 inches).

BCkyz2--37 to 41 inches; pinkish gray (7.5YR 6/2) clay loam, brown (7.5YR 4/2) moist; weak medium and coarse subangular blocky structure; hard, firm, moderately sticky and moderately plastic; few very fine roots throughout; very few prominent continuous coatings of calcium carbonate, gypsum, and other salts on surfaces of peds; 32 percent calcium carbonate equivalent; moderately saline; 15 percent gypsum; 75 percent tuff fragments that slake in water; violently effervescent; moderately alkaline; clear smooth boundary (4 to 8 inches thick).

Cr1--41 to 48 inches; weathered tuff bedrock; few prominent continuous coatings of calcium carbonate in fractures; abrupt smooth boundary.

Cr2--48 to 59 inches; weathered tuff bedrock; very few prominent continuous coatings of calcium carbonate in fractures; abrupt smooth boundary.

Cr3--59 to 80 inches; unweathered tuff bedrock; 3 percent strong brown (7.5YR 5/6) coatings in fractures; concoidal fractures; very few distinct discontinuous coatings of calcium carbonate on rock fragments.

TYPE LOCATION: Brewster County, Texas, from the junction of US Highway 90 and Texas Highway 118 in Alpine, 36.6 miles south on Texas Highway 118, 100 feet west in rangeland. Site is 0.1 mile north of second gate into 02 Ranch. Whirlwind Spring, Texas USGS topographic quadrangle; Latitude: 29 degrees, 52 minutes, 23 seconds North; Longitude: 103 degrees, 34 minutes, 41 seconds West. NAD83.

RANGE IN CHARACTERISTICS:

Soil moisture: The moisture control section is dry in all parts for less than three-fourths of the time (cumulative) when the soil temperature at a depth of 50 cm is 5 degrees Centigrade or higher, and has an aridic moisture regime that borders on an ustic moisture regime. Ustic aridic moisture regime.

Solum thickness and depth to tuff bedrock: 40 to 60 inches

Depth to a calcic and gypsic horizon: 20 to 40 inches

Silicate clay content in the particle-size control section: 35 to 50 percent

Rock fragments: 0 to 15 percent

Linear extensibility is more than 6.0 cm to a depth of 100 cm

Slickensides are not present

A horizon
Hue: 7.5YR, 10YR
Value: 4 to 6, dry or moist
Chroma: 2 to 4, dry or moist
Texture: clay loam, silty clay loam, silty clay
Other features: Some pedons have moist chroma less than 3.5, but the epipedon is not moist for 90 cumulative days in most years.
Calcium carbonate equivalent: 1 to 5 percent by volume
Reaction: slightly alkaline or moderately alkaline

Bw horizon
Hue: 7.5YR, 10YR
Value: 4 to 6, dry or moist
Chroma: 2 to 4, dry or moist
Texture: silty clay, clay
Clay content: 40 to 55 percent
Cracks: are common, but slickensides and wedge-shaped peds are not present
Calcium carbonate equivalent: 5 to 15 percent by volume
Electrical conductivity: 2 to 8 dS/m
Reaction: slightly alkaline or moderately alkaline

Bkyz horizon
Hue: 7.5YR, 10YR
Value: 4 to 6, dry or moist
Chroma: 2 to 4, dry or moist
Texture: silty clay loam, silty clay, clay
Clay content: 30 to 45 percent
Calcium carbonate equivalent: 5 to 15 percent by volume
Gypsum content: 5 to 25 percent
Electrical conductivity: 4 to 16 dS/m
Reaction: moderately alkaline

BCkyz horizon, or CBkyz horizon, where present
Hue: 7.5YR, 10YR
Value: 4 to 6, dry or moist
Chroma: of 2 to 4, dry or moist
Texture: loam, clay loam
Clay content: 20 to 35 percent
Tuff fragments: 5 to 80 percent fragments that slake in water
Calcium carbonate equivalent: 25 to 40 percent by volume
Gypsum content: 10 to 25 percent
Electrical conductivity: 8 to 16 dS/m
Reaction: moderately alkaline

Cr horizon
Other features: parent material is tuff bedrock of the Duff and Pruett Formations

COMPETING SERIES: This is the Borunda (TX) series. Borunda soils are moderately deep to a paralithic contact.

GEOGRAPHIC SETTING: Butcherknife soils are on broad alluvial flats of late-Pleistocene age. Slopes are dominantly less than 1 percent, but range up to 3 percent. The soils formed in fine textured residuum and alluvium derived from tuffaceous materials of the Duff and Pruett Formations. Mean annual precipitation ranges from 12 to 15 inches, with most occurring from July to September. Mean annual air temperature ranges from 62 to 68 degrees F. Frost free period ranges from 210 to 260 days, and elevation ranges from 3,500 to 5,000 feet.

GEOGRAPHICALLY ASSOCIATED SOILS: These are the Beewon, Borunda, Chilicotal, Quadria, and Straddlebug series. Beewon and Quadria soils have argillic horizons and are on mid-Pleistocene pediments and are higher in the landscape. Borunda soils are in the fine-loamy family, and are moderately deep to tuffaceous bedrock. They are on convex erosional hillslopes and pediments. Chilicotal soils are in the loamy-skeletal family, and are on alluvial fans. Straddlebug soils are in the fine-loamy family, and are on gently sloping Holocene-age alluvial flats and floodplains.

DRAINAGE AND PERMEABILITY: Well drained. Permeability is slow. Runoff is low on slopes less than 1 percent and medium on 1 to 3 percent slopes. Overland flow may occur once in 7 to 20 years for a duration of less than 2 days. When overland flow occurs it is usually in the months of July through September.

USE AND VEGETATION: These soils are used entirely for livestock grazing. Native vegetation is mainly drought tolerant short to mid grasses such as tobosagrass, vine mesquite, blue grama, cane bluestem, sideoats grama, and alkali sacaton. Woody species consist mainly of mesquite.

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 from Butcherknife Hill, near the type location.

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

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

Gypsic horizon - The zone from 22 to 41 inches (Bkyz, BCkyz, BCkyz horizons). Gypsum content determined by the water loss method of Nelson, Klameth and Nettleton, 1978, SSSA Journal 42: 659-661

Calcic horizon - The zone from 30 to 41 inches (BCkyz horizons)

Ustic feature - The moisture control section is dry in all parts for less than three-fourths of the time (cumulative) when the soil temperature at a depth of 50 cm is 5 degrees Centigrade or higher, and has an aridic moisture regime that borders on an ustic moisture regime

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, and laboratory data from similar soils in Presidio County, Texas.

These soils were previously included in the Verhalen series

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

Update and revision for the recorrelation of Brewster County, TX, Main Part, 2/8/08, CEM.

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

National Cooperative Soil Survey
U.S.A.