LOCATION GERTRUDIS TXEstablished Series
TAXONOMIC CLASS: Fine-loamy, mixed, active, hyperthermic Typic Calciustolls
TYPICAL PEDON: Gertrudis fine sandy loam, on a north-facing, convex, 2 percent slope in rangeland. (Colors are for dry soil unless otherwise noted.)
A1--0 to 18 centimeters (0 to 7 in); dark grayish brown (10YR 4/2) fine sandy loam, very dark grayish brown (10YR 3/2) moist; moderate fine and medium subangular blocky structure; moderately hard, friable; many fine and common medium roots; many fine and medium tubular pores; strongly effervescent; moderately alkaline, pH 8.1; clear smooth boundary.
A2--18 to 42 centimeters (7 to 17 in); very dark grayish brown (10YR 3/2) very fine sandy loam, very dark brown (10YR 2/2) moist; weak fine and medium subangular blocky structure; slightly hard, friable; many fine and common medium roots; many fine and common medium tubular pores; 3 percent fine faint threadlike white (10YR 8/1) calcium carbonate masses; strongly effervescent; moderately alkaline, pH 8.1; clear smooth boundary. {combined thickness of the A horizons is 15 to 33 cm (6 to 17 inches)}
Bk1--42 to 65 centimeters (17 to 25 in); grayish brown (10YR 5/2) sandy clay loam, dark grayish brown (10YR 4/2) moist; weak fine and medium prismatic structure parting to weak fine subangular blocky; slightly hard, friable; common very fine and fine roots; common fine and very fine tubular pores; 3 percent fine faint threadlike white (10YR 8/1) calcium carbonate masses, and 1 percent medium distinct white (10YR 8/1) calcium carbonate masses; strongly effervescent; moderately alkaline, pH 8.2; clear smooth boundary.
Bk2--65 to 103 centimeters (25 to 40 in); light brownish gray (10YR 6/2) sandy clay loam, grayish brown (10YR 5/2) moist; weak coarse prismatic structure parting to weak fine and medium subangular blocky; slightly hard, friable; common fine roots; common fine tubular pores, 5 percent fine faint threadlike white (10YR 8/1) calcium carbonate masses, and 2 percent fine distinct white (10YR 8/1) calcium carbonate masses; strongly effervescent; moderately alkaline, pH 8.2; clear smooth boundary. {combined thickness of the Bk horizons is 79 to 150 cm (31 to 59 in)}
2Bk1--103 to 128 centimeters (40 to 50 in); pale brown (10YR 6/3) clay loam, pale brown (10YR 6/3) moist; weak coarse prismatic structure parting to moderate fine and medium subangular blocky; slightly hard, friable; common fine roots; common fine tubular pores; 8 percent fine faint white (10YR 8/1) calcium carbonate masses; strongly effervescent; moderately alkaline, pH 8.2; clear smooth boundary.
2Bk2--128 to 172 centimeters (50 to 68 in); light gray (10YR 7/2) clay loam, pale brown (10YR 6/3) moist; weak fine and medium subangular blocky structure; moderately hard, friable; common fine and medium roots; common fine and medium tubular pores; 4 percent fine faint white (10YR 8/1) calcium carbonate finely disseminated throughout, 8 percent medium distinct irregular white (10YR 8/1) calcium carbonate masses, and 6 percent coarse prominent white (10YR 8/1) calcium carbonate masses; violently effervescent; moderately alkaline, pH 8.2; clear smooth boundary. {combined thickness of the 2Bk horizons is 25 to 102 cm (10 to 40 in)}
2Bk3--172 to 203 centimeters (68 to 80 in); light gray (10YR 7/2) loam, light brownish gray (10YR 6/2) moist; weak fine and medium subangular blocky structure; slightly hard, friable; 3 percent fine distinct irregular white (10YR 8/1) calcium carbonate masses, 7 percent fine faint white (10YR 8/1) calcium carbonate finely disseminated throughout, and 15 percent coarse prominent white (10YR 8/1) calcium carbonate masses; violently effervescent; moderately alkaline, pH 8.4.
TYPE LOCATION: Kleberg County, Texas; from the intersection of State Highway 141 and U.S. Highway 77 in Kingsville, 9.05 miles west on State Highway 141 to ranch road, 0.85 miles north on ranch road, 1.61 mile northwest on ranch road, 0.9 miles south on ranch road, 100 feet east in rangeland; Kingsville West, TX USGS quadrangle; Latitude, 27 degrees, 32 minutes, 58.30 seconds N; Longitude, 97 degrees, 59 minutes, 54.3 seconds W. NAD 83.
RANGE IN CHARACTERISTICS:
Soil Moisture: An ustic moisture regime. The soil moisture control section is dry in some or all parts for more than 90 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: 22.2 to 23.4 degrees C (72 to 74 degrees F).
Depth to secondary calcium carbonates: 15 to 43 cm (6 to 17 in).
Particle-size control section (weighted average) clay content: 19 to 27 percent.
A horizon
Hue: 10YR
Value: 2 to 5
Chroma: 2
Texture: fine sandy loam or loam
Clay content: 14 to 17 percent
EC (dS/cm): 0 to 1
SAR: 0 to 1
Effervescence: slightly or strongly effervescent
Reaction: neutral to moderately alkaline
Bk horizon
Hue: 10YR or 2.5Y
Value: 3 to 7
Chroma: 2 to 4
Texture: fine sandy loam, loam, sandy clay loam, or clay loam
Clay content: 19 to 32 percent
Identifiable secondary carbonates: amount-2 to 25 percent, size-fine and medium, kind-finely disseminated, irregular threadlike and masses, location-throughout
EC (dS/cm): 0 to 1
SAR: 0 to 2
Effervescence: strongly or violently effervescent
Reaction: slightly alkaline or moderately alkaline
2Bk or 2BCk (where present) horizons
Hue: 10YR or 2.5Y
Value: 5 to 7
Chroma: 2 to 4
Texture: fine sandy loam, loam, or sandy clay loam
Clay content: 17 to 32 percent
Identifiable secondary carbonates: amount-2 to 25 percent, size-fine, medium, and coarse, kind-finely disseminated, irregular threadlike, and masses, location-throughout
EC (dS/cm): 0 to 1
SAR: 0 to 2
Effervescence: strongly to violently effervescent
Reaction: slightly alkaline or moderately alkaline
Some pedons have a 2BCk horizon with properties similar to the 2Bk horizon.
COMPETING SERIES: This is the Hidalgo (TX) series. Similar soils include Benavides (TX), Engle (TX), Lupe (TX), Pernitas (TX), Pettus (TX), Pharr (TX), and Sarnosa (TX) series.
Hidalgo soils: formed in loamy and clayey alluvium on the Lower
Rio Grande Plain.
Benavides soils: have an aridic ustic moisture regime.
Engle soils: have a paralithic contact with weakly cemented sandstone.
Lupe and
Pettus soils: have a loamy-skeletal particle-size control section. In addition Pettus soils have a carbonatic mineralogy class.
Pernitas and
Pharr soils: have an argillic horizon.
Sarnosa soils: have a coarse-loamy particle-size control section and thin strata of sandstone in the lower horizons.
GEOGRAPHIC SETTING:
Parent Material: calcareous loamy alluvium overlain by eolian deposits of Quaternary age
Landform: erosional terrace remnants
Slope: 0 to 3 percent
Mean annual air temperature: 22.4 to 23.4 degrees C (72 to 74 degrees F)
Mean annual precipitation: 610 to 762 mm (24 to 30 in)
Precipitation pattern: April through June and September and October are the wettest months. November through March are the driest months.
Frost-free period: 290 to 320 days
Elevation: 6 to 91 meters (20-300 ft)
Thornthwaite annual P-E indices: 19 to 31
GEOGRAPHICALLY ASSOCIATED SOILS: These include the
Clareville,
Colmena,
Czar,
Delfina, and
Premont soils.
Clareville soils: are on concave stream terraces and have more than 35 percent clay in their particle-size control sections.
Colmena soils: are on planar to slightly convex shoulder positions and have an argillic horizon.
Czar soils: are on concave steam terraces and have a mollic epipedon more than 51 cm (20 in) thick.
Delfina and Premont soils: are on convex paleoterraces and have an argillic horizon.
DRAINAGE AND PERMEABILITY: Well drained. Permeability is moderate. Runoff is low.
USE AND VEGETATION: The major uses are crop production, livestock grazing, and wildlife habitat. Grasses present include false rhodesgrass, Kleberg bluestem, plains bristlegrass, shortspike windmillgrass, and guineagrass. Woody vegetation consists of mesquite, catclaw, elbowbush, limepricklyash, pricklypear, granjeno, and tassajillo. Crops grown include grain sorghum, watermelons and cotton. The ecological site is Gray Sandy Loam, P-E 19-31 (RO83AY388TX).
DISTRIBUTION AND EXTENT: Northern Rio Grande Plain (MLRA 83A in LRR I) and Central Rio Grande Plain (MLRA 83C in LRR I) along the margins of the Sandsheet Prairie of South Texas. The series is of moderate extent.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Temple, Texas
SERIES ESTABLISHED: Kleberg County, Texas; 2007.
REMARKS: These soils were previously included in the Hildalgo series.
Diagnostic features and horizons recognized in this pedon are:
Particle-size control section: 25 to 102 cm (10 to 40 in). (A, Bk1, and Bk2 horizons)
Mollic epipedon: 0 to 42 cm (0 to 16 in). (A1 and A2 horizons)
Calcic horizon: 65 to 203 cm (25 to 80 in). (Bk2, 2Bk1, 2Bk2 and 2Bk3 horizons)
Lithologic discontinuity: 103 to 203 cm (40 to 80 in). (2Bk horizons) Data shows the lithologic discontinuity is weakly expressed.
ADDITIONAL DATA: TAMU data from Kleberg County, Texas (S06TX-273-004)
TAXANOMIC VERSION: Keys to Soil Taxonomy, Tenth Edition, 2006.