LOCATION RANDALL TX+NM

Established Series
Rev. RM-TCB
09/2022

RANDALL SERIES

The Randall series consists of very deep, poorly drained, very slowly permeable soils that formed in clayey lacustrine sediments derived from the Blackwater Draw Formation of Pleistocene age. These nearly level soils are on the floor of playa basins 3 to 15 m (10 to 50 ft) below the surrounding plain and range in size from 10 to more than 150 acres. Slope ranges from 0 to 1 percent. Mean annual precipitation is 483 mm (19 in), and mean annual temperature is 15 degrees C (59 degrees F).

TAXONOMIC CLASS: Very-fine, smectitic, thermic Ustic Epiaquerts

TYPICAL PEDON: Randall clay, midway between microhigh and microlow, 0.2 percent slope in playa basin at an elevation of about 970 m (3,180 ft). (Colors are for moist soil unless otherwise stated.)

A1--0 to 8 cm (0 to 3 in); very dark gray (10YR 3/1) clay, dark gray (10YR 4/1) dry; moderate fine granular structure and moderate medium subangular blocky; very hard, very firm; few fine roots; common strong brown (7.5YR 5/6) masses of iron accumulation in pore linings and on surfaces of peds; few fine black (10YR 2/1) iron-manganese masses; slightly acid; clear smooth boundary.

A2--8 to 23 cm (3 to 9 in); very dark gray (10YR 3/1) clay, dark gray (10YR 4/1) dry; moderate fine and medium angular blocky structure; very hard, very firm; few fine roots; few strong brown (7.5YR 5/6) masses of iron accumulation in pore linings and on surfaces of peds; few fine black (10YR 2/1) iron-manganese masses; neutral; gradual smooth boundary. (Combined thickness of the A horizons is 13 to 40 cm)

Bw--23 to 43 cm (9 to 17 in); dark gray (10YR 4/1) clay, gray (10YR 5/1) dry; moderate fine and medium angular blocky structure; very hard, very firm; few fine roots; few fine tubular pores; few strong brown (7.5YR 5/6) masses of iron accumulation in pore linings and on surfaces of peds; few fine black (10YR 2/1) iron-manganese masses; neutral; clear wavy boundary. (0 to 25 cm thick)

Bss1--43 to 97 cm (17 to 38 in); dark gray (10YR 4/1) clay, gray (10YR 5/1) dry; moderate coarse and very coarse wedge-shaped aggregates parting to moderate medium angular blocky; extremely hard, very firm; common distinct slickensides; cracks 1.3 (0.5 in) wide extend through the horizon; few fine roots; few fine tubular pores; few fine black (10YR 2/1) iron-manganese masses and concretions; neutral; gradual wavy boundary. .

Bss2--97 to 130 cm (38 to 51 in); dark gray (2.5Y 4/1) clay, gray (2.5Y 5/1) dry; moderate coarse and very coarse wedge-shaped aggregates parting to moderate medium angular blocky; extremely hard, very firm; few fine roots; few fine tubular pores; few vertical lenses up to 1 cm (0.4 in) wide of dark gray (10YR 4/1) crack fill material; common distinct slickensides; cracks 1.3 cm (0.5 in) wide extend through the horizon; few fine black (10YR 2/1) iron-manganese concretions; neutral; gradual wavy boundary.

Bss3--130 to 157 cm (51 to 62 in); dark gray (2.5Y 4/1) clay, gray (2.5Y 5/1) dry; moderate coarse and very coarse wedge-shaped aggregates parting to moderate medium angular blocky; extremely hard, very firm; few fine tubular pores; few vertical lenses up to 1 cm (0.4 in) wide of dark gray (10YR 4/1) crack fill material; common distinct slickensides; cracks 1.3 cm (0.5 in) wide extend through the horizon; about 1 percent fine masses and nodules of calcium carbonate; slightly effervescent; moderately alkaline; gradual wavy boundary. (Combined thickness of the Bss horizons is 150 to 188 cm)

Bkss--157 to 203 cm (62 to 80 in); dark grayish brown (2.5Y 4/2) clay, grayish brown (2.5Y 5/2) dry; moderate coarse and very coarse wedge-shaped aggregates parting to weak medium angular blocky; extremely hard, very firm; few fine tubular pores; few vertical lenses up to 1 cm wide (0.4 inch) of dark gray (10YR 4/1) crack fill material; common distinct slickensides; about 3 percent fine masses and nodules of calcium carbonate; few grayish brown (2.5Y 5/2) iron depletions on surfaces of peds; slightly effervescent; moderately alkaline.

TYPE LOCATION: Floyd County, Texas; from the intersection of Farm Road 784 and U.S. Highway 70 in Floydada; 6.9 kilometers (4.3 miles west) on Farm Road 784; 1.8 kilometers (1.1 miles) south on ranch road; 91 m (300 ft) south in playa (Bois D-Arc Lake); Latitude: 33 degrees, 57 minutes, 44.13 seconds N;
Longitude: 101 degrees, 24 minutes, 57.72 seconds W; Sandhill, Texas USGS quad; NAD 83.

RANGE IN CHARACTERISTICS:
Soil moisture: An aquic moisture regime. These soils receive runoff from surrounding uplands and are moist for longer periods than normal for the climate. The soil cracks and is dry in parts of the upper 50 cm for more than 90 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. These soils receive runoff from surrounding uplands and the soil moisture control section is moist for longer periods of time than is normal for the climate of the series province.
Mean annual soil temperature: 15 to 18 degrees C (59 to 64 degrees F).
Depth to secondary calcium carbonate: 25 to more than 152 cm (10 to more than 60 in).
Depth to redox concentrations: 0 to 13 cm (0 to 5 in) and range from few to many.
Depth to redox depletions: 0 to 41 cm (0 to 16 in) and range from none to common.
Depth to episaturation: 0 to 51 cm (0 to 20 in).
Depth to slickensides: 13 to 64 cm (5 to 25 in).
Solum thickness: more than 203 cm (80 in).
Particle-size control section: 50 to 60 percent silicate clay.
This is a cyclic soil and undisturbed areas have gilgai microrelief with microhighs 8 to 13 cm (3 to 5 in) higher than microlows. Distance between the center of the microhigh and the center of the microlow are about 1.5 to 4.6 m (5 to 15 ft). The microhigh makes up about 20 percent, the intermediate, or area between the high and low, about 40 percent, and the microlow about 40 percent.
Cracks open and close each year except during higher-than-normal rainfall years, and remain open for 90 or more cumulative days during most years. When dry, 1 to 5 cm (0.4 to 2 in) wide cracks extend from the surface to a depth of 102 cm (40 in) or more. Cracks are more prominent in the microlows.
COLE is more than 0.07. The range in characteristics represents 50 percent or more of each pedon unless otherwise stated.

A horizon:
Hue: 7.5YR or 10YR
Value: 2 to 4, 3 to 5 dry
Chroma: 1 or 2
Texture: clay
Redox accumulations: masses of iron-manganese and oxidized rhizospheres range from few to many
Redox depletions: iron depletions on faces of peds and in root pores range from none to common
Effervescence: none to strong
Reaction: slightly acid to slightly alkaline

Bw horizon (where present):
Hue: N to 2.5Y
Value: 3 to 6, 4 to 7 dry
Chroma: 1 or less
Note: After periods of prolonged saturation pedons become gleyed and have neutral colors with moist color value of 4 to 6.
Texture: clay
Redox accumulations: masses of iron-manganese and oxidized rhizospheres range from few to common
Effervescence: none to strong
Reaction: neutral to moderately alkaline

Bss horizons:
Hue: N to 2.5Y
Value: 4 to 6, 5 to 7 dry
Chroma: 2 or less
Note: After periods of prolonged saturation pedons become gleyed and have neutral colors with moist color value of 4 to 6.
Texture: clay
Redox accumulations: masses of iron-manganese and oxidized rhizospheres range from none to common
Effervescence: none to strong
Reaction: neutral to moderately alkaline

Bkss horizon: (where present)
Hue: 10YR to 5Y
Value: 4 to 7, 5 to 8 dry
Chroma: 2 or less
Texture: clay
Redox accumulations: masses of iron-manganese and oxidized rhizospheres range from none to common
Calcium carbonate equivalent: less than 15 percent
Visible calcium carbonate: 3 to 10 percent as threads, masses, or nodules
Effervescence: strong or violent
Reaction: moderately alkaline

COMPETING SERIES: These are the Eastall, Ranco, Rosston, and Ustibuck series. Similar soils are the Chapel, McLean, Lazbuddie, Lockney, and Sparenberg series.
Eastall series: are in a slightly moister climate and formed in sediments derived from mixed sources.
Ranco series: has less than 50 percent clay in the particle-size control section.
Rosston and Ustibuck series: have solum thickness of 102 to 152 cm (40 and 60 in) depth.
Chapel, McLean, and Sparenberg series: do not have aquic conditions and have cracks that remains open for less than 150 cumulative days during most years.
Lazbuddie and Lockney series: do not have aquic conditions and have cracks that remain open for 150 to 210 cumulative days during most years.

GEOGRAPHIC SETTING:
Parent material: clayey lacustrine sediments derived from the Blackwater Draw Formation of Pleistocene age.
Landform: in playas 3 to 15 m (10 to 50 ft) below the surrounding plain and range in size from 10 to more than 150 acres.
Slopes: range from 0 to 1 percent.
Mean annual air temperature: 14 to 17 degrees C (57 to 62 degrees F).
Mean annual precipitation: 406 to 533 mm (16 to 21 in).
Frost-free period: 180 to 220 days.
Elevation: 732 to 1,615 m (2,400 to 5,300 ft).
Thornthwaite annual P-E Index Values: 25 to 36.

GEOGRAPHICALLY ASSOCIATED SOILS: These are the similar Lazbuddie, Lockney, and Mclean series and the Drake, Estacado, Lofton, Olton, Pep, Portales, and Pullman series.
Lazbuddie, Lockney and Mclean soils: are on similar or slightly higher landscape positions.
Arch, Portales, and Pep soils; are on slightly higher landscape positions and have 35 percent or less clay in the particle-size control section.
Drake soils: are on calcareous eolian dunes and have 35 percent or less clay in the particle-size control section.
Estacado and Pullman soils: are on surrounding plains and have an argillic horizon.
Lofton soils: are on similar or slightly higher landscape positions and have an argillic horizon.

DRAINAGE AND PERMEABILITY: Poorly drained. Very slow permeability. Surface runoff is negligible. These soils are frequently ponded for very long periods in most years.

USE AND VEGETATION: Used mainly for livestock grazing and wildlife habitat. Vegetation varies according to amount of water available. It includes knotgrass, bur ragweed, sedges, spike rushes, smartweed, saltmarsh aster, curly dock, frog-fruit, and bushy knotweed. In areas of standing water longbarb arrowhead, soft-stem bulrush and southern cattail may be present. Around the margins, where ponding occurs for shorter periods, the woody vegetation includes western willow and some cottonwood.

DISTRIBUTION AND EXTENT: Southern High Plains, Southern Part (MLRA 77C in LRR H) of western Texas and eastern New Mexico. The series is of moderate extent.

MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Temple, Texas

SERIES ESTABLISHED: Reconnaissance Soil Survey of the Panhandle Region of Texas; 1910.

REMARKS: Series Revised MLRA-77 Soil Survey; Floyd County, Texas; 1997. Classification was revised to smectitic, thermic Ustic Epiaquerts in 1997 based on soil properties and revisions to SOIL TAXONOMY. These soils have aquic conditions between 41 and 51 cm (16 and 20 in) of the soil surface in most years.
Diagnostic horizons and features recognized in this pedon are:

Mollic epipedon: 0 to 23 cm (0 to 9 in). (A horizons)
Aquic conditions: 0 to 157 cm (0 to 62 in). (A, Bw, and Bss horizons) periodic saturation, reduction and redox features.
Redox concentrations: 0 to 43 cm (0 to 17 in). (A and Bw horizons) zone of apparent accumulation of iron-manganese oxides.
Vertic feature: 43 to 208 cm (17 to 82 in) (Bss and Bkss horizons) wedge-shaped aggregates and slickensides. Deep wide cracks are open for 90 or more cumulative days in most years. Gilgai micro-relief is on undisturbed areas.

ADDITIONAL DATA: KSSL--S97TX-153-003 (Floyd County, Texas), 00TX303001 (Lubbock County, Texas), S01TX-189-001, S01TX-189-002, S01TX-189-003 (Hale County, Texas), S90NM-009-006 (Curry County, New Mexico), NSSL -- S71TX-77-1 (71L1351).
Beltsville Laboratory - 448390-448391.

Taxonomic Version: Keys to Soil Taxonomy, Twelfth Edition, 2014.

National Cooperative Soil Survey
U.S.A.