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SSM - Appendix 1. Official Soil Series Description

The descriptions, maps, and information in the appendices were generated using publically accessible websites developed and supported by the USDA Natural Resources Conservation Service. They are examples of the soil survey products discussed in this manual. These products are developed and delivered to the public with the integrated use of standardized procedures, terminology, technologies, and data systems in a cooperative environment that includes Federal, State, and local units of government and universities (i.e., the National Cooperative Soil Survey).

The appendices provide examples of four main pillars of soil survey information: (1) official soil series descriptions (OSDs), (2) detailed map unit descriptions, (3) the National Cooperative Soil Survey Soil Characterization Database, and (4) Web Soil Survey.

The OSD database is the national collection of more than 20,000 detailed soil series descriptions from across the U.S. and its territories. The OSDs are managed in a text format following specific standards for organization and content. The name of a soil series is the common reference term used in the name of soil map units. Soil series are the most homogenous classes in Soil Taxonomy. The descriptions contain soil properties that define a specific soil series and distinguish it from other soil series and serve as the basis for the taxonomic classification.

As an example, the official description of the Olton series follows.
 

Olton Series

Location, Olton: TX+NM
Established Series
Rev. TCB-JKA-RM
08/2016

The Olton series consists of very deep, well drained, moderately slowly permeable soils that formed in clayey, calcareous eolian sediments in the Blackwater Draw Formation of Pleistocene age. These soils are on nearly level to gently sloping plains and upper side slopes of playas and draws. Slope ranges from 0 to 5 percent. Mean annual precipitation is 483 mm (19 in), and mean annual temperature is 15 degrees C (59 degrees F).

TAXONOMIC CLASS: Fine, mixed, superactive, thermic Aridic Paleustolls

TYPICAL PEDON: Olton clay loam, on a northeast-facing, convex, 2 percent slope in cropland at an elevation of about 1,120 m (3,675 ft.). (Colors are for dry soil unless otherwise stated.)

A—0 to 20 cm (0 to 8 in); brown (7.5YR 4/2) clay loam, dark brown (7.5YR 3/2) moist; moderate medium granular and subangular blocky structure; hard, friable; many fine roots; common fine pores; common earthworm channels; common wormcasts; neutral; gradual smooth boundary. (15 to 36 cm [6 to 14 in] thick)

Bt1—20 to 38 cm (8 to 15 in); brown (7.5YR 4/2) clay loam, dark brown (7.5YR 3/2) moist; moderate fine and medium subangular blocky structure; very hard, firm; common fine roots; few fine pores and root channels; few distinct clay films on faces of peds; slightly alkaline; gradual wavy boundary. (10 to 25 cm [4 to 10 in] thick)

Bt2—38 to 79 cm (15 to 31 in); reddish brown (5YR 5/4) clay loam, reddish brown (5YR 4/4) moist; moderate medium angular blocky structure; very hard, firm; few fine roots, mostly between peds; earthworm channels and casts; few distinct clay films on faces of peds; noneffervescent in upper part; few films and threads of calcium carbonate at a depth of about 22 inches, slightly effervescent; moderately alkaline; gradual wavy boundary. (20 to 41 cm [8 to 16 in] thick)

Btk1—79 to 122 cm (31 to 48 in); reddish brown (5YR 5/4) clay loam, reddish brown (5YR 4/4) moist; weak medium angular blocky structure; very hard, firm; common fine root channels and pores; few distinct clay films on faces of peds; about 5 percent fine films and threads of calcium carbonate; violently effervescent; moderately alkaline; clear wavy boundary. (38 to 66 cm [15 to 26 in] thick)

Btk2—122 to 191 cm (48 to 75 in); pink (5YR 7/3) clay loam, light reddish brown (5YR 6/4) moist; weak medium angular blocky and subangular blocky structure; hard, firm; about 35 percent fine and medium calcium carbonate masses and medium and coarse calcium carbonate concretions and nodules; violently effervescent; moderately alkaline; diffuse wavy boundary. (25 to 91 cm [10 to 26 in] thick)

Btk3—191 to 251 cm (75 to 99 in); red (2.5YR 5/6) clay loam, red (2.5YR 4/6) moist; weak very coarse prismatic structure parting to moderate medium subangular blocky; very hard, firm; few distinct clay films on faces of peds and clay bridged sand grains; common soft to weakly cemented films of calcium carbonate, amount decreases with depth and is less than 2 percent in lower part of horizon; strongly effervescent ped surfaces, some noneffervescent ped interiors; moderately alkaline.

TYPE LOCATION: Randall County, Texas; from the intersection of U.S. Highways 87 and 60 in Canyon, 8.9 kilometers (5.5 miles) west on U.S. Highway 60, about 2.4 kilometers (1.5 miles) north on county road, 966 meters (0.6 mile) east and 644 m (0.4 mile) north in cultivated field or 854 m (2,800 ft.) east and 488 m (1,600 ft.) north of SE corner of sec. 7, Block 1. T. T. R. R. Survey; latitude: 35 degrees, 01 minute, 28 seconds N; longitude: 102 degrees, 01 minute, 03 seconds W; Bivins Lake, Texas USGS quad; NAD27.

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 18 degrees C (59 to 64 degrees F)
Depth to argillic horizon: 15 to 36 cm (6 to 14 in)
Depth to secondary carbonates: 36 to 71 cm (14 to 28 in)
Depth to calcic horizon: 76 to 152 cm (30 to 60 in)
Solum thickness: more than 203 cm (80 in)
Particle-size control section: 35 to 50 percent silicate clay

A horizon:
Hue: 5YR to 10YR
Value: 3 to 5, 2 to 4 moist
Chroma: 2 or 3
Texture: Loam, clay loam
Effervescence: None to slight
Reaction: Neutral to moderately alkaline

Bt horizons:
Hue: 5YR or 7.5YR
Value: 3 to 5, 2 to 4 moist
Chroma: 2 to 6
Texture: Clay loam, clay
Visible calcium carbonate: Few films and threads at about 56 cm (22 in)
Effervescence: None to slight
Reaction: Slightly alkaline or moderately alkaline

Btk horizons:
Hue: 2.5 to 7.5YR
Value: 5 to 7, 4 to 6 moist
Chroma: 3 to 8
Texture: Clay loam, silty clay loam
Visible calcium carbonate: 15 to 60 percent as masses, films, threads, concretions, and nodules
Effervescence: Violent
Reaction: Moderately alkaline or strongly alkaline

B′t horizon below the calcic (where present):
Hue: 2.5YR to 7.5YR
Value: 5 to 7, 4 to 6 moist
Chroma: 3 to 8
Texture: Loam, sandy clay loam, clay loam
Visible calcium carbonate: Few threads, films, and nodules
Effervescence: Slight or strong
Reaction: Moderately alkaline or strongly alkaline

COMPETING SERIES: There are no other series in this family. Similar soils include the Acuff, Estacado, Pullman, and Pantex series.

Acuff series: Has 18 to 35 percent silicate clay in the particle-size control section.

Estacado series: Is calcareous in upper horizons and has 20 to 35 percent silicate clay in the particle-size control section.

Pantex and Pullman series: Have COLE of more than 0.06.

GEOGRAPHIC SETTING:
Parent material: Clayey, calcareous eolian sediments in the Blackwater Draw Formation of Pleistocene age
Landform: Nearly level to gently sloping plains and upper side slopes of playas and draws
Slopes: Dominantly less than 3 percent, but can range up to 5 percent
Mean annual air temperature: 14 to 17 degrees C (57 to 62 degrees F)
Mean annual precipitation: 432 to 533 mm (17 to 21 in)
Frost-free period: 180 to 220 days
Elevation: 793 to 1,524 m (2,600 to 5,000 ft.)
Thornthwaite annual P-E Index values: 30 to 34

GEOGRAPHICALLY ASSOCIATED SOILS: These are the similar Acuff, Estacado, and Pullman series and also the Amarillo, Pep, and Portales series.

Acuff, Amarillo, and Estacado soils: Are in landscape positions similar to those of the Olton series and average less than 35 percent clay in the particle-size control section.

Pep soils: Are in landscape positions similar to those of the Olton series and do not have an argillic horizon.

Portales soils: Are in slightly lower landscape positions and average less than 35 percent clay in the particle-size control section.

Pullman soils: Are in landscape positions similar to those of the Olton series and have COLE of more than 0.06.

DRAINAGE AND PERMEABILITY: Well drained. Moderately slow permeability. Runoff is low where slopes are 0 to 1 percent and medium where slopes are 1 to 5 percent.

USE AND VEGETATION: Mainly cultivated for cotton, sorghum, and winter wheat. A considerable acreage is irrigated. Climax native vegetation is dominantly shortgrasses with a few midgrasses and includes blue grama and buffalograss. Also included are lesser amounts of vine-mesquite, western wheatgrass, sideoats grama, galleta, tobosa, silver bluestem, wild alfalfa, and prairie clover. This soil has been correlated to the Deep Hardland (077CY022TX) range site in MLRA 77C.

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

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

SERIES ESTABLISHED: Lamb County, Texas; 1960.

REMARKS: This is a Benchmark Series.

Diagnostic horizons and features recognized in this pedon are:
Mollic epipedon: 0 to 38 cm (0 to 15 in) (A, Bt1 horizons)
Argillic horizon: 20 to 251 cm (8 to 99 in) (Bt1, Bt2, Btk1, Btk2, Btk3 horizons)
Calcic horizon: 79 to 191 cm (31 to 75 in) (Btk1, Btk2 horizons)

ADDITIONAL DATA: NSSL Characterization data: Sample Nos. S78TX-381-001 and S90TX-381-001, 001A, 001B, 001C, 001D (Randall Co.); S81TX-069-001 (Castro Co.); S90TX-359-001, 001A, 001B, 001C, 001D (Oldham Co.); S81TX-069-001 and S93TX-069-001 (Castro Co.); and S92TX-369-001, 001B, 001C, 001D, 001E, 001F and S96TX-369-001, 002 (Parmer Co.). USDA-ARS Bulletin B-1727 “Olton Soils, Distribution, Importance, Variability and Management” 4-98, Paul W. Unger and Fred B. Pringle.

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

Figure A-1. Profile of the Olton series.