LOCATION PEP TX+NMEstablished Series
TAXONOMIC CLASS: Fine-loamy, mixed, superactive, thermic Aridic Calciustolls
TYPICAL PEDON: Pep clay loam, on a very gently sloping plain, 1 percent slope in cultivated land at an elevation of about 1,238 meters (4,060 feet). (Colors are for dry soil unless otherwise noted.)
A--0 to 25 cm (0 to 10 inches); reddish brown (5YR 4/3) clay loam, dark reddish brown (5YR 3/3) moist; moderate fine and medium subangular blocky structure; slightly hard, friable; common fine roots, many very fine pores; strongly effervescent; moderately alkaline; gradual smooth boundary. (13 to 36 cm thick)
Bw1--25 to 41 cm (10 to 16 inches); yellowish red (5YR 5/6) clay loam, yellowish red (5YR 4/6) moist; moderate fine and medium subangular blocky structure; hard, friable; common fine roots; common very fine pores; few threads and films of calcium carbonate; strongly effervescent; moderately alkaline; gradual smooth boundary. (13 to 43 cm thick)
Bw2--41 to 81 cm (16 to 32 inches); reddish yellow (5YR 6/6) clay loam, yellowish red (5YR 5/6) moist; moderate medium subangular blocky structure; slightly hard, friable; few fine roots; few very fine pores; few threads and films of calcium carbonate; violently effervescent; moderately alkaline; gradual irregular boundary. (0 to 48 cm thick)
Bk--81 to 203 cm (32 to 80 inches); reddish yellow (5YR 7/6) clay loam, reddish yellow (5YR 6/6) moist; moderate medium subangular blocky structure; slightly hard, friable; common very fine and fine irregular pores; about 50 percent by volume calcium carbonate as threads, films, masses, and concretions; violently effervescent; moderately alkaline.
TYPE LOCATION: Deaf Smith County, Texas; From the intersection of U. S. Highway 385 and Farm Road 1058 in Hereford, 30.6 kilometers (19.0 miles) north on U. S. Highway 385 to Farm Road 2587, 9.7 kilometers (6.0 miles) west on Farm Road 2587, 7.2 kilometers (4.5 miles) north and 644 meters (0.4 mile) east on unpaved county roads, 61 meters (200 feet) south in cultivated field; Longitude: 35 degrees, 09 minutes, 57 seconds, N; Latitude: 102 degrees, 29 minutes, 30 seconds, W; Vega South, Texas USGS quad; NAD 27.
RANGE IN CHARACTERISTICS:
Soil moisture: An ustic moisture regime bordering on aridic. The soil moisture control section is dry in some or all parts for more than 180 but less than 205 days, cumulative, in normal years. July through August and December through February are the driest months. These soils are intermittently moist in September through November and March through June.
Mean annual soil temperature: 15 to 19 degrees C (59 to 66 degrees F).
Depth to cambic horizon: 13 to 36 cm (5 to 14 inches).
Depth to secondary calcium carbonate: 13 to 51 cm (5 to 20 inches).
Depth to calcic horizon: 51 to 102 cm (20 to 40 inches).
Solum thickness: more than 203 cm (80 inches).
Particle-size control section: 18 to 35 percent silicate clay.
A horizon:
Hue: 7.5YR or 10YR
Value: 4 or 5, 2 or 3 moist
Chroma: 2 to 4
Texture: loam, clay loam
Effervescence: slight to violent
Reaction: slightly alkaline to moderately alkaline
Bw horizons:
Hue: 5YR or 7.5YR
Value: 4 to 7, 3 to 6 moist
Chroma: 2 to 6
Texture: loam, clay loam, silty clay loam
Visible calcium carbonate: l to 2 percent finely disseminated and as threads, films, and very fine and fine concretions.
Effervescence: strong to violent
Reaction: slightly alkaline to moderately alkaline
Bk horizons:
Hue: 5YR or 7.5YR
Value: 6 to 8, 5 to 7 moist
Chroma: 2 to 4
Texture: loam, clay loam, silty clay loam
Visible calcium carbonate: l5 to 60 percent finely disseminated and as threads, films, masses, and fine and medium concretions.
Calcium carbonate equivalent: 15 to 50 percent.
Effervescence: violent
Reaction: moderately alkaline
COMPETING SERIES: These are the
Mansic (OK),
Murray (TX),
Portales (NM) and the tentative
Snyder (TX) series. Similar soils include the
Estacado,
Mansker,
Plemons, and
Zita series.
Mansic series: has less than 10 percent whitish concretions or other masses of segregated calcium carbonate in the Bk horizon and is 25 to 51 cm (10 to 20 inches) deep to the zone of lime segregation.
Murray series: occurs on piedmont slopes and fan terraces.
Portales series: has a calcic horizon at 13 to 38 cm (5 to 15 inches) depth and does not have colors 7.5YR or redder.
Estacado, Mansker, and Plemons series: have an argillic horizon.
Snyder series: depth to a calcic horizon is less than 50 cm (20 in).
Zita series: is not calcareous above the calcic horizon and does not have colors redder than 7.5YR.
GEOGRAPHIC SETTING:
Parent material: medium to moderately fine textured, calcareous, mixed eolian sediments derived from Blackwater Draw Formation of Pleistocene age.
Landform: on nearly level to gently sloping plains and side slopes above playas and along draws with plane to convex surfaces.
Slopes: 0 to 5 percent.
Mean annual air temperature: 14 to 18 degrees C (57 to 64 degrees F).
Mean annual precipitation: 406 to 559 millimeters (16 to 22 inches).
Frost-free period: 180 to 210 days.
Elevation: 762 to 1,463 meters (2,500 to 4,800 feet).
Thornthwaite annual P-E Index Values: 22 to 32.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the competing
Portales series, the similar
Estacado and
Zita soils and
Acuff,
Olton,
Pantex, and
Pullman series.
Portales, Estacado and Zita soils: are on similar or slightly lower landscape positions.
Acuff soils: are on similar landscape positions and have an argillic horizon.
Olton, Pantex, and Pullman soils: are on similar landscape positions, have an argillic horizon, and average more than 35 percent clay in the particle-size control section.
DRAINAGE AND PERMEABILITY: Well drained. Moderate permeability. Surface runoff is negligible on 0 to 1 percent slopes, very low on 1 to 3 percent slopes, and low on 3 to 5 percent slopes.
USE AND VEGETATION: Widely used for dryland and irrigated crop production. Principal crops grown are cotton, grain sorghum, and wheat. Climax native vegetation is mainly mid and short grasses and includes blue grama, sideoats grama, and buffalograss, with lesser amounts of vine-mesquite, western wheatgrass, galleta or tobosa, silver bluestem, wild alfalfa, and prairieclover with a light to moderate overstory of mesquite. This soil has been correlated to the Loamy (077CY028TX) range site in MLRA-77.
DISTRIBUTION AND EXTENT: Southern High Plains, Southern Part (MLRA 77C in LRR H) of west Texas and eastern New Mexico. This series is extensive.
MLRA OFFICE RESPONSIBLE: Temple, Texas
SERIES ESTABLISHED: Series proposed Deaf Smith County, Texas; 1991, Established Deaf Smith County, Texas; 1999.
REMARKS: This soil was formerly included with the Portales and Zita series.
Diagnostic horizons and features recognized in this pedon are:
Mollic epipedon: 0 to 25 cm. (A horizon)
Cambic horizon: 25 to 81 cm. (Bw horizon)
Calcic horizon: 81 to 203 cm. (Bk horizon)
ADDITIONAL DATA: none
TAXONOMIC VERSION: Keys to Soil Taxonomy, Tenth Edition, 2006.