LOCATION CAYO TXEstablished Series
TAXONOMIC CLASS: Coarse-loamy, mixed, semiactive, hyperthermic Typic Calciustepts
TYPICAL PEDON: Cayo fine sandy loam--in slightly concave interdune, with a 0 to 1 percent slope, at an elevation of 6.3 m (20 ft), in rangeland. (Colors are for dry soil unless otherwise stated)
A1--0 to 13 cm (O to 5 in); grayish brown (10YR 5/2) fine sandy loam, dark grayish brown (10YR 4/2) moist; moderate fine and medium subangular blocky structure; slightly hard, very friable; common fine and few medium roots; few fine and medium pores; strongly effervescent; slightly alkaline; clear smooth boundary.
A2--13 to 31 cm (5 to 12 in); grayish brown (2.5Y 5/2) fine sandy loam, dark grayish brown (2.5Y 4/2) moist; moderate medium subangular blocky structure parting to weak fine subangular blocky; slightly hard, very friable; few fine and medium roots; few fine and medium pores; strongly effervescent; slightly alkaline; clear smooth boundary. (combined thickness of the A horizons is 15 to 36 cm [6 to 14 in])
Bk--31 to 48 cm (12 to 19 in); light brownish gray (2.5Y 6/2) fine sandy loam, grayish brown (2.5Y 5/2) moist; moderate medium subangular blocky structure; slightly hard, very friable; few fine and medium roots; few fine and medium pores; 10 percent grayish brown (2.5Y 5/2) land crab krotovinas; violently effervescent; moderately alkaline; gradual smooth boundary. (thickness of the Bk horizon is 10 to 23 cm [4 to 9 in])
Bknzl--48 to 71 cm (19 to 28 in); light gray (2.5Y 7/2) fine sandy loam, light brownish gray (2.5Y 6/2) moist; weak medium prismatic structure parting to moderate medium subangular blocky; slightly hard, very friable; few fine and medium roots; few fine and medium pores; few fine masses of calcium carbonate; few land crab remains; 15 percent grayish brown (2.5Y 5/2) land crab krotovinas; moderately saline; moderately sodic; violently effervescent; strongly alkaline; gradual smooth boundary.
Bknz2--71 to 104 cm (28 to 41 in); light gray (2.5Y 7/2) fine sandy loam, light brownish gray (2.5Y 6/2) moist; moderate medium prismatic structure parting to weak medium subangular blocky; slightly hard, very friable, few fine and medium roots; common fine and medium pores; few fine masses of calcium carbonate; few land crab remains; 15 percent grayish brown (2.5Y 5/2) land crab krotovinas; moderately saline; moderately sodic; violently effervescent; strongly alkaline; gradual smooth boundary.
2Bknz3--104 to 130 cm (41 to 51 in); pale olive (5Y 6/4) fine sandy loam, olive (5Y 5/3) moist; weak medium prismatic structure parting to moderate medium subangular blocky; hard, friable; few fine and medium roots; few fine and medium pores; few fine and medium masses of calcium carbonate; common land crab remains; 15 percent grayish brown (2.5Y 5/2) land crab krotovinas; moderately saline; moderately sodic; violently effervescent; strongly alkaline; gradual smooth boundary.
2Bknz4--130 to 155 cm (51 to 61 inches); pale olive (5Y 6/4) fine sandy loam, olive (5Y 5/3) moist; weak medium prismatic structure parting to moderate medium subangular blocky; hard, friable; few fine and medium roots; few fine and medium pores; many fine and medium masses of calcium carbonate; 15 percent grayish brown (2.5Y 5/2) land crab krotovinas; few medium distinct olive yellow masses of oxidized iron with diffuse boundaries; strongly saline; moderately sodic; violently effervescent; strongly alkaline; gradual smooth boundary. (combined thickness of the Bknz horizons is 64 to 130 cm [25 to 51 in])
2Bnz--155 to 203 cm (61 to 80 in); pale olive (5Y 6/4) fine sandy loam, olive (5Y 5/3) moist; weak medium prismatic structure parting to weak coarse subangular blocky; slightly hard, friable; few fine and medium roots; few fine and medium pores; few medium elongated segregation of calcium carbonate vertically oriented; few coarse distinct olive brown masses of oxidized iron with diffuse boundaries; strongly saline; moderately sodic; noneffervescent; moderately alkaline.
TYPE LOCATION: Kenedy County, Texas; from the intersection of La Parra Avenue and U.S. Highway 77 in Sarita, 15 miles south on U.S. Highway 77 to ranch east gate, 7.8 miles southeast on ranch road, 4.7 miles south on ranch road, generally east 7.8 miles where road goes southeast, continue southeast 0.25 miles; site is 30 feet north of road in rangeland. San Pedro Ranch, Texas USGS topographic quadrangle; Latitude: 26 degrees, 52 minutes, 56 seconds N.; Longitude: 97 degrees, 38 minutes, 37.5 seconds W., NAD 83.
RANGE IN CHARACTERISTICS:
Soil Moisture: An ustic moisture regime. The soil moisture control section (SMCS) is dry in some or all parts for more than 90 days cumulative in normal years. The SMCS is also either moist in some or all parts for 180 cumulative days or more, or moist for 90 or more consecutive 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.
Depth to secondary calcium carbonate: 15 to 38 cm (6 to 15 in)
Depth to cambic horizon: 15 to 36 cm (6 to 14 in)
Depth to calcic horizon: 36 to 76 cm (14 to 30 in)
Depth to redox concentrations: 102 to 152 cm (40 to 60 in)
Depth to redox depletions: 102 to 152 cm (40 to 60 in)
Particle-size control section (weighted average)
Clay content: 11 to 18 percent
A horizon
Hue: 10YR or 2.5Y
Value: 5 or 6
Chroma: 2 or 3
Texture: fine sandy loam, loam
Clay content: 11 to 18 percent
Calcium carbonate equivalent: 0 to 15 percent
EC (dS/m): 0 to 4 in the upper 51 cm (20 in)
SAR: 0 to 3
Effervesce: strongly to violently
Reaction: moderately alkaline or strongly alkaline
Bk and Bknz horizons
Hue: 10YR or 2.5Y
Value: 5 to 7
Chroma: 2 or 3
Texture: fine sandy loam, loam, or sandy clay loam
Clay content: 11 to 18 percent
Calcium carbonate equivalent: 8 to 20 percent
EC (dS/m): 8 to 16
SAR: 10 to 35
Effervesce: strongly to violently
Reaction: moderately alkaline or strongly alkaline
2Bknz and 2Bnz horizons
Hue: 5Y
Value: 5 or 6
Chroma: 2 to 4
Texture: fine sandy loam, loam, or sandy clay loam
Clay content: 11 to 18 percent
Calcium carbonate equivalent: 1 to 10 percent
EC (dS/m): 16 to 32
SAR: 15 to 50
Effervesce: strongly to violently
Reaction: moderately alkaline or strongly alkaline
COMPETING SERIES: There are no competing series in the same family. Similar soils are
Atco (TX),
Dill (OK),
Hardeman (TX),
Karnes (TX),
Lalinda (TX) and
Saspamco (TX) series.
Atco and Karnes soils: have carbonatic mineralogy, in addition, Karnes soils have a thermic temperature regime.
Dill and Hardeman soils: have thermic temperature regime.
Lalinda soils: are in a fine-loamy family.
Saspamco soils: are well drained.
GEOGRAPHIC SETTING:
Parent material: sandy eolian deposits of Holocene age over loamy sediments of Quaternary age.
Landform: Interdunes associated with dunal passage on the Sandsheet
Slope: 0 to 1 percent
Mean annual soil temperature: 22 to 23 degrees C (72 to 74 degrees F)
Mean annual precipitation: 635 to 711 mm (25 to 28 in)
Frost-free period: 310 to 341 days
Elevation: 3 to 31 m (10 to 100 ft)
Thornthwaite P-E Index: 31 to 44
GEOGRAPHICALLY ASSOCIATED SOILS: These are the
Falfurrias,
Sarita, and
Topo series.
Falfurrias and Sarita soils: have sandy surface layers more than 40 inches thick and are in higher convex positions
Topo soils: are saline throughout the pedon, saturated for longer periods, and are in lower deflation swales
DRAINAGE AND PERMEABILITY: Moderately well drained. Moderately rapid permeability. Runoff is negligible.
USE AND VEGETATION: Used for livestock grazing and wildlife habitat. Native vegetation is mesquite, lotebush, whitebrush, spiny hackberry, Brazil, tasajillo, Hooded windmillgrass, Bermudagrass, Texas bristlegrass, Purple threeawn, and Western ragweed. The ecological site is Sandy loam, PE 31 to 44 (R083EY702TX).
DISTRIBUTION AND EXTENT: Sandsheet Prairie (MLRA 83E in LRR I) of southern Texas. The series is of moderate extent.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Temple, Texas
SERIES ESTABLISHED: Kenedy County, Texas, 2007. The name is from a lake in Kenedy County, Texas.
REMARKS: Classification changed from Typic Ustochrepts to Typic Haplustepts based on application of the eighth edition of Keys to Soil Taxonomy. Classification changed from Typic Haplusteps to Typic Calciustepts based on application of the tenth edition of the Keys to Soil Taxonomy.
Diagnostic horizons and features recognized in this pedon are:
Ochric epipedon: 0 to 31 cm (0 to 12 in) (A horizons)
Cambic horizon: 31 to 38 cm(12 to 51 in) (Bk, Bknz, and 2Bknz3 horizons)
Calcic hoizon: 48 to 104 cm (19 to 41 in) (Bknz1 and Bknz2 horizons)
Redoximorphic concentrations: 130 to 203 cm (51 to 80 in) (2Bknz4 and 2Bnz horizons)
Lithologic discontinuity: at 104 cm (41 in) at the upper boundary of the 2Bknz3 horizon, and at 155 cm (61 in) at the upper boundary of the 3Bnz horizon. Discontinuity expressed in the ration increases of the sand to silt particle size on a clay free basis.
ADDITIONAL DATA: TAMU data from Kenedy County, TX (S88TX-261-006).
TAXONOMIC VERSION: Keys to Soil Taxonomy, Tenth Edition, 2006