LOCATION QUEMADO TXEstablished Series
TAXONOMIC CLASS: Loamy-skeletal, mixed, superactive, hyperthermic, shallow Ustalfic Petrocalcids
TYPICAL PEDON: Quemado very gravelly sandy loam in rangeland. (Colors are for dry soil unless otherwise stated.)
A--0 to 13 cm (0 to 5 in); brown (7.5YR 4/4) very gravelly sandy loam, dark brown (7.5YR 3/4) moist; weak granular structure; hard, friable, slightly sticky and nonplastic; 50 percent rounded quartz, chert, sandstone, and igneous gravel; neutral; clear smooth boundary. (8 to 20 cm [3 to 8 in] thick)
Bt--13 to 31 cm (5 to 12 in); reddish brown (5YR 4/4) very gravelly sandy loam; dark reddish brown (5YR 3/4) moist; weak granular structure; hard, friable, slightly sticky and nonplastic; few faint clay films on surfaces of peds and coarse fragments; about 55 percent rounded gravel; neutral; abrupt wavy boundary. (13 to 31 cm [5 to 12 in] thick)
Bkkm1--31 to 61 (12 to 24 in); pinkish white (7.5YR 8/2) strongly cemented calcium carbonate, having few fractures; finely laminated and indurated in upper part; about 50 percent embedded rounded siliceous gravel; moderately alkaline; diffuse irregular boundary. (10 to 46 cm [4 to 18 in] thick)
Bkkm2--61 to 203 cm (24 to 80 in) pinkish white (7.5YR 8/2) weakly cemented calcium carbonate; massive; about 50 percent siliceous gravel; moderately alkaline.
TYPE LOCATION: Kinney County, Texas; from the intersection of U.S. Highways 90 and 277 in Del Rio, 14.7 miles south on U.S. Highway 277 to Canal Headgate Road; 1.6 miles west on Canal Headgate Road; 100 feet south into rangeland. Cow Creek Tank, TX USGS topographic quadrangle. Latitude: 29 degrees, 11 minutes, 50.235 seconds N.; Longitude: 100 degrees, 44 minutes, 57.933 seconds W.; NAD 83.
RANGE IN CHARACTERISTICS:
Soil Moisture: An aridic soil moisture regime bordering on ustic. The soil moisture control section is dry in all parts for less than 270 cumulative days in normal years. The soil is driest during the months of May through July and December through February. These soils are intermittently moist in August through November and March through April.
Surface coverage: 30 to 90 percent rounded pebbles
Solum thickness: 25 to 51 cm (10 to 20 in)
Mean annual soil temperature: 22 to 24 degrees C (72 to 76 degrees F).
Depth to argillic horizon: 8 to 23 cm (3 to 9 in) (A horizon)
Depth to petrocalcic horizon: 20 to 51 cm (8 to 20 in)
Particle-size control section (weighted average)
Clay content: 13 to 26 percent
Coarse fragments: 35 to 80 percent
CEC/clay ratio: 0.60 to 0.90
A horizon
Hue: 5YR or 7.5YR
Value: 3 to 5
Chroma: 2 to 4
Texture: very gravelly or extremely gravelly sandy loam or loam
Clay content: 10 to 21 percent
Coarse fragments: 35 to 80 percent
Base saturation: 100 percent
Calcium carbonate equivalent: 0 to trace
Identifiable secondary carbonate: none
EC (dS/m): 0 to 1
Gypsum: 0 to trace
SAR: 0 to trace
Effervescence: none to very slight
Reaction: slightly acid to slightly alkaline
Bt horizon
Hue: 5YR or 7.5YR
Value: 4 or 5
Chroma: 2 to 6
Texture: very gravelly or extremely gravelly sandy loam, loam, or sandy clay loam
Clay content: 13 to 26 percent
Clay films: few to common, faint to distinct, of surfaces of peds and lining pores
Coarse fragments: 35 to 80 percent quartz, chert, limestone, and indurated caliche, or igneous rocks
Base saturation: 100
Calcium carbonate equivalent: 0 to 1 percent
Identifiable secondary calcium carbonate: none
EC (dS/m): 0 to 1
Gypsum: 0 to 1 percent
SAR: 0 to 1
Effervescence: none to slightly
Reaction: neutral or slightly alkaline
The Bkkm1 horizon
Hue: 7.5YR
Value: 7 or 8
Chroma: 2 to 4
Coarse fragments: about 50 percent embedded rounded siliceous gravel
This horizon is moderately or strongly cemented in the upper part.
The Bkkm2 horizon
Hue: 7.5YR
Value: 7 or 8
Chroma: 2 to 4
Coarse fragments: about 50 percent siliceous gravel
This horizon is weakly cemented.
COMPETING SERIES: There are no competing series in the same family. Similar soils are the
Grava (TX),
Hollace (NV),
Jimenez (TX),
Mata (TX),
Plaintank (AZ),
Terino (NM), and
Yologo (TX) series.
Grava, Jimenez, and Yologo soils: have mollic epipedons, in addition the Grava soils are clayey-skeletal
Hollace and Plaintank soils: are in the mesic soil temperature regime.
Mata soils: are deep to weathered shale bedrock and do not have a petrocalcic horizon.
Terino soils: are in the thermic soil temperature regime.
GEOGRAPHIC SETTING:
Parent material: gravelly loamy alluvium derived from the Uvalde Gravel.
Landform: knobs on paleoterraces.
Slope: 0 to 8 percent.
Mean annual air temperature: 21 to 23 degrees C (70 to 74 degrees F).
Mean annual precipitation: 432 to 635 mm (17 to 25 in).
Precipitation pattern: moist spring and fall months and dry summer and winter months.
Frost-free period: 260 to 360 days.
Elevation: 31 to 274 m (100 to 900 ft).
Thornthwaite annual P-E indices: 24 to 28.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the
Delmita,
Jimenez,
Olmos, and
Zapata series. (This aridisol is currently associated with soils in the ustic/aridic soil moisture regime. Associated soils will be evaluated in the future to insure proper taxonomic placement. This section will be updated to reflect any changes that may occur.)
Delmita soils: are in the fine-loamy family and are on similar positions
Jimenez and Olmos soils: have a mollic epipedon, no argillic horizons and are on lower positions
Zapata soils: are not gravelly, do not have an argillic horizons and are on lower positions
DRAINAGE AND PERMEABILITY: Well drained. Permeability is moderate above the very slowly permeable petrocalcic horizon. Runoff is negligible on slopes less than 1 percent, low on 1 to 5 percent slopes, and medium on 5 to 8 percent slopes.
USE AND VEGETATION: Used for livestock grazing and wildlife habitat. Vegetation is a sparse cover of red grama, hairy tridens, threeawn, and Hall's panicum, and woody shrubs including cenizo, catclaw acacia, pricklypear, and some cacti. Ecological site is Gravelly Ridge 18-35 PZ (R083BY419TX).
DISTRIBUTION AND EXTENT: Western Rio Grande Plain, Texas; LRR I, MLRA 83B. The series is of large extent.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Temple, Texas
SERIES ESTABLISHED: Kinney County, Texas, 1965.
REMARKS: Classification change from Ustalfic Paleargids to Ustic Petroargids based on application of the second edition of Soil Taxonomy, 1999. Classification change from Ustic Petroargids to Ustalfic Petrocalcids based on application of the Keys of Soil Taxonomy, Tenth Edition, 2006.
Diagnostic horizons and features recognized in this pedon are:
Particle size control section: 13 to 31 cm (5 to 12 in). (Bt horizon)
Ochric epipedon: 0 to 13 cm (0 to 5 in) (A horizon) .
Argillic horizon: 13 to 31 cm (5 to 12 in) (Bt horizon).
Petrocalcic horizon: 13 to 203 cm (12 to 80 in) (Bkkm horizons).
Additional data: The assignment of cation exchange capacity is inferred from surrounding surveys.
Taxonomic version: Keys to Soil Taxonomy, Tenth Edition, 2006.