LOCATION PICOSA TX

Established Series
Rev. CLG-FBT-CLN
11/2010

PICOSA SERIES

The Picosa series consists of very shallow to shallow, well drained, moderately permeable soils. These soils formed in tuffaceous weakly cemented sandstone bedrock interbedded with claystone of the Jackson Group. These nearly level to hilly soils are on uplands. Slopes are 0 to 40 percent but are mainly 1 to 5 percent. Mean annual precipitation is about 736 mm (29 in) and the mean annual temperature is about 22 degrees C (72 degrees F).

TAXONOMIC CLASS: Loamy, mixed, superactive, hyperthermic, shallow Entic Haplustolls

TYPICAL PEDON: Picosa loam in rangeland; elevation is 123 meters (405 feet). (Colors are for dry soil unless otherwise stated.)

A--0 to 15 cm (0 to 6 in); dark grayish brown (10YR 4/2) loam, very dark grayish brown (10YR 3/2) moist; moderate fine subangular blocky and granular structure; hard, firm; common fine roots; contains an estimated 12 percent by volume of weakly cemented tuffaceous sandstone from 2 mm to 25 mm in diameter; slightly alkaline; diffuse wavy boundary. (Thickness is 10 to 25 cm [4 to 10 in].)

AC--15 to 25 cm (6 to 10 in); very dark grayish brown (10YR 3/2) loam, very dark grayish brown (10YR 3/2) moist (A); very pale brown (10YR 8/2), weakly cemented, partially weathered, tuffaceous sandstone and claystone fragments; light gray (10YR 7/2) moist; weak fine subangular blocky structure in the A part; very hard, firm; about 35 percent masses and seams of dark grayish brown (10YR 4/2)loam throughout; slightly alkaline; abrupt wavy boundary. (Thickness is 8 to 25 cm [3 to 10 in].)

Cr--25 to 38 cm (10 to 15 in); very pale brown (10YR 8/2) weakly cemented sandstone bedrock with interbedded layers of claystone; slightly alkaline.

TYPE LOCATION: Wilson County, Texas; from the intersection of Farm Road 541 and U.S. Highway 181 in Poth; 7 miles west on Farm Road 541; 5.5 miles southwest on Farm Road 1344; 75 feet west of intersection of unpaved road and Farm Road 1344. Three Oaks, Texas USGS topographic quadrangle; Latitude: 28 degrees, 57 minutes, 34.16 seconds N; Longitude: 98 degrees, 8 minutes, 50.40 seconds W.: NAD 83.

RANGE IN CHARACTERISTICS:

Soil Moisture: A typic-ustic moisture regime. The soil moisture control section is dry in some or all parts for more than 90 days but less than 180 cumulative days in normal years. June through August and December through February are the driest months. These soils are intermittently moist in September through November and March through May.
Mean annual soil temperature: 22 to 23 degrees C (72 to 74 degrees F)
Depth to weakly cemented sandstone: 13 to 36 cm (5 to 14 in). Weakly consolidated sandstone fragments cover 0 to 30 percent of the soil surface.

A horizon:
Hue: 10YR
Value: 3 to 5
Chroma 1 to 3
Texture: fine sandy loam, sandy clay loam, loam, or clay loam
Clay content: 18 to 35 percent
Rock Fragments: 0 to 20 percent weakly consolidated sandstone
Reaction: slightly alkaline or moderately alkaline
Effervescence: noneffervescent.

AC horizon:

A part
Hue: 10YR
Value: 3 to 5
Chroma 1 to 3
Texture: fine sandy loam, sandy clay loam, loam, or clay loam
Clay content: 18 to 35 percent
Identifiable secondary carbonates: 0 to 5 percent, fine to coarse, threadlike, masses, and nodules on rock fragments and in the matrix
Rock Fragments: 0 to 20 percent weakly consolidated sandstone
Reaction: slightly alkaline or moderately alkaline
Effervescence: noneffervescent.
C part
Hue: 10YR
Value: 6 to 8
Chroma 1 to 3
Texture: fragments of weakly cemented tuffaceous sandstone and claystone bedrock
Reaction: neutral to moderately alkaline
Effervescence: noneffervescent to slight

Cr horizon:
Hue: 10YR or 2.5 Y
Value: 6 to 8
Chroma 1 to 3
Some pedons contain yellowish brown staining on the unweathered fragments and secondary carbonate concentrations.
Texture: weakly cemented tuffaceous sandstone bedrock interbedded with claystone of the Jackson Group.
Reaction: neutral to moderately alkaline
Effervescence: noneffervescent to slight

COMPETING SERIES: There are no series in the same faimly. Similiar soils include the Harper, Hidalgo, Renick, Talpa, and Tarrant series.
Harper: mean annual soil temperature less than 22 degrees (72 degrees F) and are underlain with limestone and have more than 35 percent clay in the particle-size control section
Hidalgo: are more than 20 inches deep and have a calcic horizon
Renick: mean annual soil temperature less than (22 degrees) (72 degrees F), have more than 35 percent clay in the control section and are underlain by serpentine
Talpa: mean annual soil temperature less than 22 degrees (72 degrees F), underlain by limestone and have a calcic horizon
Tarrant: mean annual soil temperature less than 22 degrees (72 degrees F), underlain by limestone and have a calcic horizon

GEOGRAPHIC SETTING:
Parent material: tuffaceous sandstone and claystone sediments containing volcanic ash or shards on geological formations of the Jackson group
Landscape: inland, dissected coastal plain
Landform: cuestas
Slope: 0 to 40 percent
Mean annual precipitation: 660 to 864 mm (26 to 34 in)
Mean annual temperature: 21 to 23 degrees C (70 to 73 degrees F)
Frost-free period: 275 to 292 days
Elevation: 30 to 244 m (100 to 800 ft)
Thornthwaite annual P-E indices: 38 to 42

GEOGRAPHICALLY ASSOCIATED SOILS: These include the Coy (TX), Tordia (TX), and Weigang (TX) series.
Coy soils: are on a lower, less sloping landscape position; have an argillic horizon
Tordia: are on a lower, less sloping landscape position; clayey throughout; more than 50 cm (20 in) deep
Weigang: on a similar landscape position; have an argillic horizon

DRAINAGE AND PERMEABILITY: Well drained. Permeability is moderate. Runoff is negligible on 0 to 1 percent slopes, very low on 1 to 3 percent slopes, low on 3 to 5 percent slopes, medium on 5 to 20 percent slopes, and high on 20 to 40 percent slopes.

USE AND VEGETATION: Used mostly for rangeland. The present vegetation is mainly fall witchgrass, hairy grama, lovegrass tridens, plains bristlegrass, Nash windmillgrass, slim tridens, with an overstory of mesquite, guajillo, blackbrush, lote, and catclaw, plus annual weeds and grasses.

DISTRIBUTION AND EXTENT: Northern Rio Grande Plain, Texas; LRR I; MLRA 83A. moderate extent.

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

SERIES ESTABLISHED: Wilson County, Texas; 1972.

REMARKS: The Picosa series is named after an intermittent stream in Wilson County.

Diagonostic horizons and features recognized in this pedon are:
Particle size control section: 0 to 15 cm (0 to 6 in) (A horizon)

Mollic epipedon: 0 to 15 cm (0 to 6 in). (A horizon)

Paralithic contact: 25 to 38 cm (10 to 15 in). (top of Cr layer)

ADDITIONAL DATA: Particle Size Analysis, pH, EC were performed at the project office on one pedon in McMullen County.

TAXONOMIC VERSION: Keys to Soil Taxonomy, Eleventh Edition, 2010

National Cooperative Soil Survey
U.S.A.