LOCATION GARCENO TXEstablished Series
TAXONOMIC CLASS: Fine, mixed, superactive, hyperthermic Aridic Haplustepts
TYPICAL PEDON: Garceno clay loam, on an east facing, convex, 1.5 percent slope in rangeland; elevation is 122 m (400 ft). (Colors are for dry soil unless otherwise stated.)
A1--0 to 5 cm (0 to 2 in), pale brown (10YR 6/3) clay loam, dark grayish brown (10YR 4/2) moist; upper 1-2 cm (1/2 in), weak fine granular structure; slightly hard, friable, sticky and plastic; common fine roots and pores; 5 percent fine calcium carbonate masses; 2 percent by volume of intact snail shells; 1 percent medium rounded siliceous pebbles on the surface; strongly effervescent, moderately alkaline; clear smooth boundary. (3 to 8 cm [1 to 3 in]thick)
A2--5 to 23 cm (2 to 9 in), brown (10YR 5/3) clay loam, brown (10YR 4/3) moist; moderate fine subangular blocky structure; hard, friable, sticky and plastic; 3 percent fine roots; common fine pores; 2 percent threads of calcium carbonate; 3 percent broken snail shells; strongly effervescent, moderately alkaline; diffuse smooth boundary. (15 to 33 cm [6 to 13 in] thick)
Bk1--23 to 69 cm (9 to 27 in), pale brown (10YR 6/3) clay loam, brown (10YR 4/3) moist; moderate fine subangular blocky structure; hard, friable, sticky and plastic; few fine roots; common fine and medium pores; common wormcasts; 4 percent smooth siliceous pebbles up to 3 cm (1 in) in diameter; 8 percent threads and films of calcium carbonate; violently effervescent, moderately alkaline; diffuse wavy boundary. (36 to 76 cm [14 to 30 in] thick)
Bk2--69 to 86 cm (27 to 34 in), very pale brown (10YR 7/3) clay loam, brown (10YR 5/3) moist; moderate medium subangular blocky structure; hard, friable, sticky and plastic; few fine pores; 5 percent smooth pebbles up to 3 cm (1 in) in diameter; 10 percent masses, threads, and films of calcium carbonate; violently effervescent, moderately alkaline; gradual wavy boundary. (8 to 25 cm [3 to 10 in] thick)
Bkyz--86 to 203 cm (34 to 80 in), very pale brown (10YR 7/3) clay loam; moderate fine subangular blocky structure; hard, friable, sticky and plastic; few fine pores; 1 percent smooth siliceous pebbles; 5 percent fine gypsum crystals; 8 percent fine thread-like white 10YR 8/1 salt masses; 6 percent medium masses and common films and threads of calcium carbonate; violently effervescent, moderately alkaline.
TYPE LOCATION: Starr County, Texas; from the intersection of U.S. Highway 83 and Loma Blanca Road (This intersection is four miles north of Roma); 9.1 miles north on Loma Blanca Road to unpaved county road; 0.6 mile east on unpaved county road; 200 feet north in rangeland. El Chapote, Texas USGS topographic quadrangle. Latitude: 26 degrees, 35 minutes, 28 seconds N.; Longitude: 98 degrees, 59 minutes, 55 seconds W.; NAD 83.
RANGE IN CHARACTERISTICS:
Soil Moisture: An ustic soil moisture regime bordering aridic. The soil moisture control section remains moist in some or all parts for less than 90 consecutive days in normal years. The soil is driest during the months of June through August and December through February. These soils are intermittently moist in September through November and March through May.
Solum thickness: more than 203 cm (80 in)
Mean annual soil temperature: 22 to 24 degrees C (72 to 76 degrees F).
Depth to cambic horizon: 18 to 41 cm (7 to 16 in) A horizon.
Particle-size control section (weighted average)
Clay content: 35 to 50 percent
Coarse Fragments: 0 to 5 percent
CEC/clay ratio: 0.60 to 0.80
A horizon
Hue: 7.5YR or 10YR
Value: 4 to 6
Chroma: 2 or 3. Surface layers with dry value less than 5.5 and 3.5 moist are less than 25 cm (10 in) thick.
Texture: clay loam, silty clay loam, or clay
Clay content: 32 to 45 percent
Base saturation: 100 percent
Calcium carbonate equivalent: 0 to 10 percent
Identifiable secondary carbonate: 0 to 2 percent, fine threads.
EC (dS/m): 0 to 4
SAR: 0 to 10
Effervescence: slightly to strongly effervescent
Reaction: moderately alkaline
Bk horizon
Hue: 7.5YR or 10YR
Value: 5 or 6
Chroma: 2 or 3
Texture: clay loam or clay
Clay content: 35 to 50 percent
Base saturation: 100
Calcium carbonate equivalent: 5 to 14 percent
Identifiable secondary carbonate: 1 to 19 percent, fine to coarse, films, threads, and masses on surfaces of peds and in ped interiors.
EC (dS/m): 0 to 8
SAR: 5 to 30
Effervescence: strongly or violently effervescent
Reaction: moderately alkaline
Bkyz horizon
Hue: 7.5YR or 10YR
Value: 6 or 7
Chroma: 3 or 4
Texture: clay loam or clay
Clay content: 35 to 50 percent
Base saturation: 100
Calcium carbonate equivalent: 5 to 14 percent
Identifiable secondary carbonate: 1 to 19 percent, fine to coarse, films, masses, threads, on surfaces of peds and in ped interiors.
EC (dS/m): 0 to 16
SAR: 5 to 30
Effervescence: violently effervescent
Reaction: moderately alkaline
COMPETING SERIES: These are no competing series in the same family. Similar soils are the
Bookout (TX),
Calendar (NM),
Copita (TX),
Kobarter (MT),
Maverick (TX),
Reynosa (TX), and
Viboras (TX) series.
Bookout soils: are in a fine-silty family.
Calendar soils: are in a mesic soil temperature regime.
Copita and Reynosa soils: have less than 35 percent clay in the particle size control section. In addition, Copita soils are moderately deep to weathered sandstone bedrock.
Kobarter soils: are in a frigid soil temperature regime.
Maverick and Viboras soils: are moderately deep to weathered shale bedrock. In addition, Viboras soils have hues redder than 7.5YR.
GEOGRAPHIC SETTING:
Parent material: calcareous clayey alluvium.
Landform: interfluves
Slope: 0 to 2 percent
Mean annual air temperature: 22 to 23 degrees C (71 to 74 degrees F).
Mean annual precipitation: 508 to 635 mm (20 to 25 in).
Precipitation pattern: moist spring and fall months and dry winter and summer months.
Frost-free period: 280 to 360 days.
Elevation: 46 to 168 m (150 to 550 ft).
Thornthwaite annual P-E indices: 20 to 28.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the Copita, Catarina, Maverick, and Uvalde series.
Copita soils: are on higher positions
Catarina soils: are Vertisols and are in similar positions
Maverick soils: are on higher positions
Uvalde soils: have a mollic epipedon and are on similar positions
DRAINAGE AND PERMEABILITY: Well drained. Permeability is moderately slow. Runoff is low on slopes less than 1 percent and medium on 1 to 2 percent slopes.
USE AND VEGETATION: Mostly native rangeland and wildlife habitat. The main grasses include Arizona cottontop, two-flower trichloris, plains bristlegrass, curlymesquite grass, and Texas bristlegrass. Woody species include a dense cover of lotebush, guayacan, spiny hackberry, and mesquite. Heavy stands of the guajillo shrub occur in some places. The ecological site is Clay Loam 18-25 PZ (R083BY416TX).
DISTRIBUTION AND EXTENT: Western Rio Grande Plain, Texas; LRR I; MLRA 83B; the series is of moderate extent.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Temple, Texas.
SERIES ESTABLISHED: Jim Hogg County, Texas, 1970.
REMARKS: Diagnostic horizons and features recognized in this pedon are:
Particle size control section: 25 to 102 cm (10 to 40 in) (Bk and Bkyz horizons)
Ochric epipedon: 0 to 23 cm (0 to 9 in) (A horizon)
Additional data: NSSL data number SO2-TX-427-001 from Starr County, Texas. NSSL lab data shows a fine-loamy control section but local data supports fine control section. The assignment of the cation-exchange activity class is inferred from lab data collected in surrounding surveys.
Taxonomic version: Keys to Soil Taxonomy, Tenth Edition, 2006.