LOCATION LOFTON TX+NMEstablished Series
TAXONOMIC CLASS: Fine, mixed, superactive, thermic Vertic Argiustolls
TYPICAL PEDON: Lofton clay loam, on north-facing, nearly level, 0.5 percent slope within playa basin in cropland at an elevation of about 1,032 meters (3,385 feet). (Colors are for dry soil unless otherwise stated.)
Ap--0 to 23 cm (0 to 9 inches); dark gray (10YR 4/1) clay loam, very dark gray (10YR 3/1) moist; weak fine granular structure; hard, friable; common fine roots; common fine pores; slightly alkaline; abrupt smooth boundary. (10 to 25 cm thick)
Bt1--23 to 61 cm (9 to 24 inches); dark grayish brown (10YR 4/2) clay, very dark grayish brown (10YR 3/2) moist; moderate medium blocky structure; extremely hard, firm; common many fine roots; many fine pores; common prominent clay films on surfaces of peds; slightly alkaline; gradual smooth boundary.
Bt2--61 to 97 cm (24 to 38 inches); grayish brown (10YR 5/2) clay, dark grayish brown (10YR 4/2) moist; strong medium angular blocky structure; extremely hard, very firm; common fine roots; common fine pores; common prominent clay films on surfaces of peds; some peds are wedge-shaped and have pressure faces tilted 10 degrees to 15 degrees from horizontal; few films and threads of calcium carbonate in lower part; matrix is noneffervescent; moderately alkaline; gradual wavy boundary. (20 to 51 cm thick)
Btk--97 to 132 cm (38 to 52 inches); grayish brown (10YR 5/2) clay, dark grayish brown (10YR 4/2) moist; moderate medium blocky structure; very hard, firm; few very fine roots; common distinct clay films on surfaces of peds; about 2 percent visible calcium carbonate in the form of threads and films; strongly effervescent; moderately alkaline; clear smooth boundary. (25 to 76 cm thick)
Bk--132 to 203 cm (52 to 80 inches); grayish brown (10YR 5/2) silty clay, dark grayish brown (10YR 4/2) moist; weak medium angular blocky structure; hard, friable; common distinct clay films on surfaces of peds; about 25 percent visible calcium carbonate in the form of threads, masses, and concretions; violently effervescent; moderately alkaline.
TYPE LOCATION: Armstrong County, Texas; from the intersection of U.S. Highway 287 and Texas State Highway 207 in Claude, 2.4 kilometers (1.5 miles) south on Texas State Highway 207, 805 meters (0.5 mile) west on county road, and 31 meters (100 feet) north of road in cropland; Latitude: 35 degrees, 05 minutes, 30 seconds N; Longitude: 101 degrees, 22 minutes, 25 seconds W; Claude, Texas USGS quad; NAD 27.
RANGE IN CHARACTERISTICS:
Soil moisture: An typic-ustic moisture regime. The soil moisture control section is dry in some or all parts more than 90 but less than 180 cumulative days in normal years. July through August and November through March are the driest months. These soils are intermittently moist in September through October and April through June. The soil receives runoff from surrounding soils and the soil moisture control section is moist for longer periods than that of the surrounding soils.
Mean annual soil temperature: 15 to 18 degrees C (59 to 64 degrees F).
Depth to argillic horizon: 15 to 25 cm (6 to 10 inches).
Depth to secondary calcium carbonate: 51 to 102 cm (20 to 40 inches).
Depth to calcic horizon: 102 to 152 cm (40 to 60 inches).
Vertic properties: When dry, cracks 0.6 to 2.5 cm (0.25 to 1 inch) wide extend to depths of 51 cm (20 inches) or more. COLE in the upper 51 cm (20 inches) of the Bt2 and ranges from 0.15 to 0.23 cm (0.06 to 0.09 inches) wide in the upper 102 cm (40 inches).
Solum thickness: more than 203 cm (80 inches).
Particle-size control section: 35 to 50 percent silicate clay.
Ap horizon:
Hue: 10YR or 2.5Y
Value: 3 or 4, 2 or 3 moist
Chroma: 1 or 2
Texture: silty clay loam, clay loam
Reaction: neutral to moderately alkaline
Effervescence: none
Bt horizons:
Hue: 10YR or 2.5Y
Value: 3 to 5, 2 to 4 moist
Chroma: 1 to 3
Texture: silty clay, clay
Reaction: slightly alkaline to moderately alkaline
Effervescence: none or slight
Btk horizon: (where present)
Hue: 10YR or 2.5Y
Value: 5 to 8, 4 to 7 moist
Chroma: 1 to 6
Texture: clay loam, silty clay, clay
Calcium carbonate equivalent: 5 to 30 percent
Visible secondary calcium carbonate: 3 to 40 percent in the form of films, threads, masses, or nodules
Reaction: moderately alkaline
Effervescence: violent
Bk horizon: (where present)
Hue: 10YR or 2.5Y
Value: 5 to 8, 4 to 7 moist
Chroma: 1 to 6
Texture: clay loam, silty clay, clay
Calcium carbonate equivalent: 5 to 40 percent
Visible secondary calcium carbonate: 15 to 50 percent in the form of films, threads, masses, or concretions
Reaction: moderately alkaline
Effervescence: violent
COMPETING SERIES: This is the
Culp series in the same family. Similar soils include
Lazbuddie,
Lockney,
McLean,
Olton,
Pantex,
Pullman, and
Westill series.
Culp series: is moist in the soil moisture control section for longer periods and have mean annual soil temperatures of more than 20 degrees C (68 degrees F).
Lazbuddie series: have an ochric epipedon.
Lockney and McLean series: do not have an argillic horizon.
Olton, Pantex, Pullman series: have hues of 7.5YR or redder in matrix.
Westill series: have an active cation-exchange activity class.
GEOGRAPHIC SETTING:
Parent material: clayey eolian sediments of the Blackwater Draw Formation of Pleistocene age.
Landform: nearly level playa terraces, floors of shallow playa basins, or slight depressions on nearly level plains.
Slopes: 0 to 1 percent.
Mean annual air temperature: 14 to 17 degrees C (57 to 62 degrees F).
Mean annual precipitation: 432 to 533 millimeters (17 to 21 inches).
Frost-free period: 180 to 220 days.
Elevation: 793 to 1,402 meters (2,600 to 4,600 feet).
Thornthwaite annual P-E Index Values: 30 to 34.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the similar
Lazbuddie,
Lockney, and
McLean series and the
Olton,
Pantex,
Pullman,
Portales,
Randall, and
Zita series.
Lazbuddie and Lockney soils: are on similar landscape positions, do not have an argillic horizon, and have 50 to 60 percent clay in the particle-size control section.
McLean and Randall soils: are on slightly lower landscape positions and have 50 to 60 percent clay in the particle-size control section.
Olton, Pantex, and Pullman soils: are on slightly higher landscape positions on surrounding nearly level plains and have hues of 7.5YR or redder in the lower part.
Portales and Zita soils: have a cambic horizon and have less than 35 percent clay in the particle-size control section.
DRAINAGE AND PERMEABILITY: Moderately well drained. Very slow permeability. Surface runoff is low on less than one percent slopes. These soils are occasionally ponded for very brief periods.
USE AND VEGETATION: Mainly cultivated to cotton, grain sorghum, corn, and winter wheat. Native vegetation varies according to amount of water available. It includes western wheatgrass, vine-mesquite, buffalograss, blue grama, knotgrass, and bur ragweed. Sedges, spike rushes, and curly dock occur in wetter areas. This soil has been correlated to the Playa (077CY027TX) range site in MLRA-77.
DISTRIBUTION AND EXTENT: Southern High Plains, Southern Part (MLRA 77A in LRR H) of western Texas and eastern New Mexico. The series is moderately extensive.
MLRA OFFICE RESPONSIBLE: Temple, Texas
SERIES ESTABLISHED: Harding County, New Mexico; 1940.
REMARKS: Series revised MLRA-77 Soil Survey update of Carson County, Texas; 1998 with minor revision in 2007.
Diagnostic horizons and features recognized in this pedon are:
Mollic epipedon: 0 to 61 cm. (A and Bt1 horizons)
Argillic horizon: 23 to 132 cm. (Bt1, Bt2, and Btk horizons)
Calcic horizon: 132 to 203 cm. (Bk horizon)
Vertic feature: COLE is more than 0.06 within 102 cm (40 inches) of the soil surface.
ADDITIONAL DATA: NSSL data from Hale County, TX (S01TX-189-004).
TAXONOMIC VERSION: Keys to Soil Taxonomy, Tenth Edition, 2006.