LOCATION OPTIMA KS+TX NM OKEstablished Series
TAXONOMIC CLASS: Mixed, mesic Aridic Ustipsamments
TYPICAL PEDON: Optima loamy fine sand--on a 10 percent convex slope in rangeland at an elevation of about 1,036 meters (3,400 feet). (Colors are for dry soil unless otherwise noted.)
A1--0 to 20 cm (0 to 8 inches); pale brown (10YR 6/3) loamy fine sand, brown (10YR 5/3) moist; single grain; loose, soft, non-sticky and non-plastic; common fine and medium roots; neutral; clear smooth boundary.
A2--20 to 43 cm (8 to 17 inches); 60 percent brown (10YR 5/3) and 40 percent light yellowish brown (10YR 6/4) fine sand, 60 percent brown (10YR 4/3) and 40 percent yellowish brown (10YR 5/4) moist; single grain; loose, soft, non-sticky and non-plastic; few fine and medium roots; neutral; gradual smooth boundary. (combined thickness of the A horizons is 10 to 50 cm [4 to 20 inches])
C1--43 to 152 cm (17 to 60 inches); brownish yellow (10YR 6/6) fine sand, yellowish brown (10YR 5/6) moist; weak coarse prismatic structure parting to single grain; loose, soft, non-sticky and non-plastic; few very fine and fine roots; neutral; gradual wavy boundary.
C2--152 to 203 cm (60 to 80 inches); light yellowish brown (10YR 6/4) fine sand, yellowish brown (10YR 5/4) moist; weak coarse prismatic structure parting to single grain; loose, soft, non-sticky and non-plastic; few very fine and fine roots; neutral.
TYPE LOCATION: Morton County, Kansas; about 11.3 kilometers (7 miles) north and 2.4 kilometers (1.5 miles) east of Rolla; 732 meters (2,400 feet) south and 457 meters (1,500 feet) west of the northeast corner of section 31, Township 32 South, Range 39 West; Latitude 37 degrees, 13 minutes, 19 seconds north; Longitude 101 degrees, 35 minutes, 52 seconds west, NAD 83.
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 220 days, cumulative, in normal years. July through August and December through February is the driest months. These soils are intermittently moist in September through November and March through June.
Mean annual soil temperature: 12 to 14 degrees C (55 to 58 degrees F).
Particle-size control section: 3 to 10 percent silicate clay.
A horizon
Hue: 7.5YR or 10YR
Value: 5 to 8, 4 to 7 moist
Chroma: 2 to 6
Texture: loamy fine sand or fine sand
Effervescence: none
Reaction: neutral or slightly alkaline
C horizon:
Hue: 7.5YR to 10YR
Value: 5 to 8, 4 to 7 moist
Chroma: 2 to 6
Texture: fine sand, loamy fine sand, sand
Effervescence: none
Reaction: neutral or slightly alkaline
COMPETING SERIES: These are the Blueridge, Colfer, Dankworth, Royosa, and Scoville series. Similar soils also include the Likes,
Milsand, Nutivoli,
Tivoli, and
Valentine series.
Blueridge soils: have 15 to 35 percent coarse fragments throughout the particle size control section.
Colfer soils: have a lithologic discontinuity and depth to a calcic horizon that ranges between 102 to 152 cm (40 to 60 inches).
Dankworth soils: have 2 to 15 percent coarse fragments throughout the particle-size control section and have slightly cooler average soil temperature.
Royosa soils: are dry in the soil moisture control section for longer periods.
Scoville soils: have a lithologic discontinuity that ranges between 102 to 140 cm (40 to 60 inches).
Likes, Milsand, and Nutivoli soils: are in a thermic soil temperature regime.
Tivoli and Valentine soils: are moist in the soil moisture control section for longer periods.
GEOGRAPHIC SETTING:
Parent material: sandy eolian sediments of Holocene age.
Landform: dune
Slopes: 1 to 15 percent.
Elevation: 920 to 1,478 meters (2,800 to 4,500 feet)
Mean annual air temperature: 11 to 13 degrees C (52 to 56 degrees F).
Mean annual precipitation: 356 to 483 mm (14 to 19 inches).
Frost-free period: 150 to 200 days
Thornthwaite annual P-E Index Values: 25 to 36
GEOGRAPHICALLY ASSOCIATED SOILS: These are the Dalhart,
Dumas, Conlen, Eva, and
Sunray soils.
Conlen soils: are on a lower landscape position and have carbonatic mineralogy.
Dalhart, Dumas, Eva, and Sunray soils: are on lower landscape positions and have an argillic horizon.
DRAINAGE AND PERMEABILITY: Excessively drained and rapidly permeable. Runoff is negligible on slopes less than 5 percent and very low on 5 to 15 percent slopes.
USE AND VEGETATION: Mainly used for livestock grazing. Climax vegetation is tall and mid-grasses, with sand bluestem, little bluestem, giant sandreed, and switchgrass dominating. Sand paspalum, sideoats grama, hairy grama and perennial threeawn are the main mid and short grasses. Sand sagebrush, shinoak, and skunkbush are the main shrubs. This is a fragile site and is subject to severe wind erosion if not protected by cover. This soil has been correlated to the Sand Hills (R-077AY011TX) ecological site in MLRA-77A.
DISTRIBUTION AND EXTENT: Southern High Plains, Northern Part (MLRA 77A in LRR H) of northwestern Texas Panhandle, northeastern New Mexico, southwestern Kansas, and the western Oklahoma Panhandle. These soils are moderate in extent.
MLRA OFFICE RESPONSIBLE: Temple, Texas
SERIES ESTABLISHED: Morton County, Kansas, 1995.
REMARKS: These soils were previously included in the Valentine series. Classification change from Typic Ustipsamments to Aridic Ustipsamments based on the evaluation of geographic distribution and occurrence of the soil.
Diagnostic horizons and features recognized in this pedon are:
Ochric epipedon: 0 to 43 cm. (A horizon)
ADDITIONAL DATA: none
TAXONOMIC VERSION: Keys to Soil Taxonomy, Tenth Edition, 2006.