LOCATION LEONCITA TX

Established Series
CKH-JBA
11/2010

LEONCITA SERIES

The Leoncita series consists of very deep, well drained, moderately permeable soils that formed in calcareous loamy alluvium of Pleistocene age. These nearly level to moderately sloping soils are on risers and treads of remnant paleoterraces. Slopes range from about 0 to 5 percent. Mean annual precipitation is about 635 mm (25 in) and mean annual air temperature is about 22 degrees C (72 degrees F).

TAXONOMIC CLASS: Fine-loamy, mixed, superactive, hyperthermic Aridic Calciustolls

TYPICAL PEDON: Leoncita fine sandy loam, on an east facing, 3 percent slope in rangeland; elevation is 95 meters (311 feet). (Colors are for dry soil unless otherwise stated.)

Ap1--0 to 12 cm (0 to 5 in); very dark grayish brown (10YR 3/2) fine sandy loam, very dark brown (10YR 2/2) moist; weak medium subangular blocky structure; slightly hard, firm, nonsticky; common fine and very fine roots; common fine pores; few snail shells; 3 percent quartzite gravels in soil and on surface; slightly alkaline; clear smooth boundary.

Ap2--12 to 28 cm (5 to 11 in); dark grayish brown (10YR 4/2) fine sandy loam, very dark grayish brown (10YR 3/2) moist; weak medium subangular blocky structure; slightly hard, firm, nonsticky; common fine and medium roots; common fine pores; few snail shells; slightly effervescent; moderately alkaline; clear smooth boundary. (combined thickness of the Ap horizon is 15 to 36 cm [6 to 14 in])

Bk1--28 to 40 cm (11 to 17in); grayish brown (10YR 5/2) sandy clay loam, dark grayish brown (10YR 4/2) moist; weak medium subangular blocky structure; moderately hard, very firm, nonsticky; few fine roots; few fine pores; 3 percent fine threadlike masses of calcium carbonate in the matrix; slightly effervescent; moderately alkaline; gradual smooth boundary.

Bk2--40 to 104 cm (17 to 41 in); pale brown (10YR 6/3) sandy clay loam, brown (10YR 5/3) moist; weak coarse subangular blocky structure; moderately hard, very firm, nonsticky; few very fine roots; few fine pores; 5 percent fine threadlike masses of calcium carbonate in the matrix; strongly effervescent; moderately alkaline; gradual wavy boundary.

Bk3--104 to 160 cm (41 to 63 in); very pale brown (10YR 7/3) loam, pale brown (10YR 6/3) moist; weak coarse subangular blocky structure; slightly hard, firm, slightly sticky; 3 percent common medium irregular carbonate nodules and 15 percent medium irregular masses of calcium carbonate in the matrix; violently effervescent; moderately alkaline; gradual smooth boundary. (combined thickness ot the Bk horizon is 115 to 173 cm [46 to 68 in])

Bk4--160 to 203 cm (63 to 80 in); very pale brown (10YR 7/3) sandy clay loam, pale brown (10YR 6/3) moist; weak coarse subangular blocky structure; slightly hard, firm, slightly sticky; 5 percent medium irregular masses of calcium carbonate in the matrix; violently effervescent; moderately alkaline.

TYPE LOCATION: McMullen County, TX; from the intersection of Texas Highway 72 and U.S. Highway 16 in Tilden, about 4 miles west on Texas highway 72; 0.5 mile south on New Teal Ranch Road; located about feet 1,375 ft west in rangeland. Tilden, Texas USGS topographic quadrangle; Latitude: 28 degrees, 27 minutes, 41.92 seconds N; Longitude: 98 degrees, 37 minutes, 10.16 seconds W.; NAD 83.

RANGE IN CHARACTERISTICS:

Soil Moisture: An aridic ustic moisture regime. The soil moisture control section is moist in some or all parts for less than 90 consecutive days in normal years. June to August and December to February are the driest months, while September to November and March to May are the wettest months.
Mean annual soil temperature: 21 to 23 degrees C (70 to 73 degrees F)
Particle-size control section (weighted average): 18 to 25 percent (carbonate clay-free basis)
Depth to secondary calcium carbonate: 28 to 203 cm (11 to 80 in)
Depth to calcic horizon: 28 to 160 cm (11 to 63 in)

Particle-size control section (weighted average)
Clay content: 18 to 30 percent

A Horizon
Hue: 10YR
Value: 3 to 5
Chroma: 1 to 3
Texture: fine sandy loam or sandy clay loam
Clay content: 15 to 25 percent
Calcium carbonate equivalent: 0 to 5 percent
EC (dS/m): 0 to 1
SAR: 0 to 1
Effervescence: none to slight
Reaction: slightly alkaline or moderately alkaline

Bk Horizon
Hue: 10YR
Value: 3 to 8
Chroma: 1 to 4
Texture: clay loam, sandy clay loam or loam
Clay content: 18 to 32 percent
Coarse fragments: 0 to 10 percent
Calcium carbonate equivalent: 10 to 25 percent
Identifiable secondary carbonate: 2 to 20 percent, fine medium and coarse, masses and nodules, throughout
EC (dS/m): 0 to 1
SAR: 0 to 2
Effervescence: slight to violent
Reaction: slightly alkaline or moderately alkaline

COMPETING SERIES: These are the Benavides (TX), and Houla (TX) series. Similar soils are the Hidalgo (TX), Pharr (TX), and Sarnosa (TX ) series.
Benavides soils: formed in residuum from the Goliad Formation; allow for hue redder than 10YR in the calcic horizon
Houla soils: contain volcanic ash in the sand fraction and developed in residuum derived from
the tuffaceous Catahoula Formation; allows clay loam, silty clay loam and silty clay in the surface horizon
Hidalgo soils: are moist for more than 90 days, consecutive, in normal years (typic-ustic moisture regime).
Pharr soils: have an argillic horizon
Sarnosa soils: have less than 18 percent clay in the particle size control section

GEOGRAPHIC SETTING:
Parent material: calcareous alluvium derived from sedimentary rocks
Landform: remnant paleoterrace
Slope: 0 to 5 percent
Mean annual air temperature range: 21 to 24 degrees C (70 to 74 degrees F)
Mean annual precipitation range: 558 to 660 mm (22 to 26 in)
Frost-free period: 275 to 320 days
Elevation: 65 to 115 m (213 to 377 ft)
Thornthwaite annual P-E indices: 30 to 44

GEOGRAPHICALLY ASSOCIATED SOILS: These are the Caid (TX), Chacon (TX), Colmena (TX), Hindes(TX) series.

Caid, Chacon, and Colmena soils: have an argillic horizon and are on a similar landform.
Hindes soils: have a clayey-skeletal particle size control section and are on a similar landform

DRAINAGE AND PERMEABILITY: Well drained. Permeability is moderate. Runoff is low.

USE AND VEGETATION: Used mostly for livestock grazing and wildlife habitat. Some areas are crop production, mostly for grain sorghum. Present vegetation includes pink pappusgrass, lovegrass tridens, fall witchgrass, hooded windmillgrass, and plains bristlegrass. Woody vegetation includes mesquite, catclaw, spiny hackberry, and blackbrush, and guallijo.
DISTRIBUTION AND EXTENT: Western and Central Rio Grande Plain, Texas; LRR I; MLRA 83B and 83C; The series is of moderate extent.

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

SERIES PROPOSED: McMullen County, Texas, 2010. The name is from a stream in McMullen County.

REMARKS: The series was formerly included in the Hidalgo series. The Hidalgo series parent material is associated with deltas and coastal terraces. The series was separated based on the source and age of the alluvium. Leoncita soils formed from inland calcareous loamy alluvium of Pleistocene age associated with remnant paleoterraces.

Diagnostic horizons and features recognized in this pedon are:
Particle size control section: 25 to 100 cm (10 to 40 in). (Ap2, Bk1, Bk2 horizon)

Mollic epipedon: 0 to 28 cm (0 to 11 in). (Ap horizons)

Calcic horizon: 40 to 160 cm (11 to 63 in). (Bk1, Bk2, and Bk3 horizons)

ADDITIONAL DATA: Local lab data was run on particle-size analysis, calcium carbonate equivalent and pH were at the project office on S08TX3117106. The assignment of the cation-exchange activity class is inferred from lab data from Live Oak County, Texas on soils derived from similar sediments.

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

National Cooperative Soil Survey
U.S.A.