LOCATION MONTEALTO TXEstablished Series
TAXONOMIC CLASS: Fine, mixed, active, hyperthermic Ustic Epiaquerts
TYPICAL PEDON: Montealto clay--on a concave, 0 to 1 percent slope in a depression in rangeland at an elevation of 5 m (16 feet). (Colors are for dry soil unless otherwise stated.)
A1--0 to 13 cm (0 to 5 in); very dark gray (10YR 3/1) clay, black (10YR 2/1) moist; moderate fine and medium angular blocky structure; extremely hard, very firm, very sticky, very plastic; 7 percent fine and medium roots; 5 percent very fine and fine tubular pores; 7 percent fine prominent yellowish brown (10YR 5/6) masses of oxidized iron with sharp boundaries lining pores; 3 percent fine and medium faint dark gray (10YR 4/1) iron depletions with diffuse boundaries in the matrix; noneffervescent; slightly acid, pH 6.1; clear smooth boundary.
A2--13 to 43 cm (5 to 17 in); very dark gray (10YR 3/1) clay, black (10YR 2/1) moist; moderate fine and medium angular blocky structure; extremely hard, very firm, very sticky, very plastic; 5 percent very fine and fine roots; 3 percent very fine and fine pores; 2 percent fine distinct dark yellowish brown (10YR 4/4) masses of oxidized iron with sharp boundaries lining pores; 3 percent fine prominent dark gray (10YR 4/1) and 2 percent fine and medium faint light brownish gray (10YR 6/2) iron depletions with clear boundaries in the matrix; noneffervescent; slightly acid, pH 6.4; clear smooth boundary. (combined thickness of the A horizon is 20 to 56 cm [8 to 22 in])
Bss--43 to 71 cm (17 to 28 in); dark gray (10YR 4/1) clay, very dark gray (10YR 3/1) moist; moderate fine and medium angular blocky structure; extremely hard, very firm, very sticky, very plastic; 3 percent very fine and fine roots; 3 percent very fine and fine pores; 8 percent faint slickensides; 2 percent fine distinct dark yellowish brown (10YR 4/4) masses of oxidized iron with sharp boundaries lining pores; 3 percent fine and medium faint gray (10YR 5/1) iron depletions with diffuse boundaries in the matrix; noneffervescent; neutral, pH 7.3; clear smooth boundary.(Bss horizon is 18 to 38 cm {7 to 15 in} thick)
Bkss1--71 to 94 cm (28 to 37 in); gray (10YR 5/1) clay, dark gray (10YR 4/1) moist; moderate fine and medium angular blocky structure; extremely hard, very firm, very sticky, very plastic; 2 percent very fine and fine roots; 3 percent very fine and fine pores; 20 percent distinct slickensides; 2 percent fine iron-manganese nodules; 1 percent fine prominent light yellowish brown (2.5Y 6/4) masses of oxidized iron with sharp boundaries lining pores; 3 percent fine and medium distinct grayish brown (10YR 5/2) and 5 percent medium faint very dark gray (10YR 3/1) iron depletions with clear boundaries in the matrix; 2 percent fine and medium weakly cemented nodules of calcium carbonate; noneffervescent; moderately alkaline, pH 8.0; clear smooth boundary.
Bkss2--94 to 117 cm (37 to 46 in); gray (10YR 5/1) clay, dark gray (10YR 4/1) moist; moderate fine and medium angular blocky structure; extremely hard, very firm, very sticky, very plastic; 1 percent very fine and fine roots; 1 percent very fine and fine pores; 25 percent distinct slickensides; 2 percent fine iron-manganese concretions; 5 percent fine and medium faint very dark gray (10YR 3/1) and 7 percent medium distinct grayish brown (2.5Y 5/2) iron depletions with clear boundaries in the matrix; 2 percent fine weakly cemented nodules of calcium carbonate; noneffervescent; strongly alkaline, pH 8.5; clear smooth boundary.
Bkss3--117 to 150 cm (46 to 59 in); light brownish gray (2.5Y 6/2) clay, grayish brown (2.5Y 5/2) moist; moderate fine and medium angular blocky structure; extremely hard, very firm, very sticky, very plastic; 1 percent very fine and fine roots; 1 percent very fine and fine pores; 20 percent distinct slickensides; 3 percent fine iron-manganese concretions; 5 percent medium faint light yellowish brown (2.5Y 6/3) masses of oxidized iron with clear boundaries lining pores; 3 percent fine and medium distinct very dark gray (10YR 3/1) iron depletions with clear boundaries in the matrix; 2 percent fine weakly cemented nodules of calcium carbonate; noneffervescent; moderately alkaline, pH 8.3; clear smooth boundary. (combined thickness of the Bkss horizon is 61 to 163 cm [24 to 64 in])
BC1--150 to 180 cm (59 to 71 in); light brownish gray (2.5Y 6/2) clay, grayish brown (2.5Y 5/2) moist; weak fine and medium angular blocky structure; extremely hard, very firm, very sticky, very plastic; 3 percent fine iron-manganese concretions; 7 percent medium faint light yellowish brown (2.5Y 6/3) masses of oxidized iron with clear boundaries in the matrix; 2 percent fine and medium distinct dark gray (10YR 4/1) iron depletions with clear boundaries in the matrix; 1 percent medium masses of calcium carbonate; noneffervescent; moderately alkaline, pH 8.3; clear smooth boundary. (combined thickness of the BCg horizon is 0 to 81 cm [0 to 32 in])
BC2--180 to 203 cm (71 to 80 in); light brownish gray (2.5Y 6/2) clay, grayish brown (2.5Y 5/2) moist; weak fine and medium angular blocky structure; extremely hard, very firm, very sticky, very plastic; 3 percent fine and medium iron-manganese concretions; 10 percent medium faint pale yellow (2.5Y 7/3), 3 percent medium faint pale olive (5Y 6/3), and 2 percent fine distinct yellowish brown (10YR 5/4) masses of oxidized iron with clear boundaries in the matrix; 3 percent medium distinct grayish brown (10YR 5/2) iron depletions with clear boundaries in the matrix; 1 percent medium masses of calcium carbonate; noneffervescent; moderately alkaline, pH 8.4.
TYPE LOCATION: Kenedy County, Texas; from the intersection of U.S. Highway 77 and La Parra Avenue in Sarita; 38.65 miles south on U.S. Highway 77; 1.9 miles east on ranch road; 800 feet south on ranch road; 0.67 mile generally east on ranch road; 400 feet southeast in depression. Rosita Lake, Texas USGS topographic quadrangle; Latitude: 26 degrees, 39 minutes, 37.2 seconds N; Longitude: 97 degrees, 43 minutes, 34.2 seconds W; NAD 83.
RANGE IN CHARACTERISTICS:
Soil Moisture: An aquic soil moisture regime.
Mean annual soil temperature: 22.2 to 23.4 degrees C (72 to 74 degrees F)
Depth to secondary calcium carbonate: 61 to 100 cm (24 to 40 in)
Depth to masses of oxidized iron: 0 to 51 cm (0 to 20 in)
Depth to iron depletions: 0 to 100 cm (0 to 40 in)
Depth to episaturation: 0 to 61 cm (0 to 24 in) in most years from September to April. The soil is ponded to a depth of 12 inches for short periods after heavy precipitation events.
Vertic features: 38 to 150 cm (15 to 60 inches)
Particle-size control section (weighted average)
Clay content: 40 to 55 percent
A horizon
Hue: 10YR
Value: 3 to 5, 2 to 4 moist
Chroma: 1
Texture: clay loam or clay
Clay content: 35 to 55 percent
Redox concentrations: amount-0 to 7 percent, size-fine, contrast-distinct or prominent, boundary-sharp or clear
Redox depletions: amount-0 to 3 percent, size-fine or medium, contrast-faint or distinct, boundary-clear or diffuse
EC (dS/m): 0 to 2
SAR: 0 to 4
Effervescence: none
Reaction: moderately acid to neutral
Bss horizon
Hue: 10YR or 2.5Y
Value: 4 to 6, 3 to 5 moist
Chroma: 1 or 2
Texture: clay
Clay content: 40 to 60 percent
Redox concentrations: amount-1 to 10 percent, size-fine or medium, contrast-faint to prominent, boundary-sharp or clear
Redox depletions: amount-0 to 7 percent, size-fine or medium, contrast-faint or distinct, boundary-clear or diffuse
EC (dS/m): 0 to 4
SAR: 0 to 8
Effervescence: none
Reaction: neutral to strongly alkaline
Bkss horizon
Hue: 10YR or 2.5Y
Value: 4 to 6, 3 to 5 moist
Chroma: 1 or 2
Texture: clay
Clay content: 40 to 60 percent
Redox concentrations: amount-1 to 10 percent, size-fine or medium, contrast-faint to prominent, boundary-sharp or clear
Redox depletions: amount-0 to 12 percent, size-fine or medium, contrast-faint or distinct, boundary-clear or diffuse
Identifiable secondary carbonate: amount-0 to 2 percent, size-fine or medium, location- throughout
EC (dS/m): 0 to 4
SAR: 0 to 8
Effervescence: none
Reaction: neutral to strongly alkaline
BC horizon
Hue: 10YR or 2.5Y
Value: 5 to 7, 4 to 6 moist
Chroma: 2
Texture: clay loam, sandy clay or clay
Clay content: 30 to 60 percent
Redox concentrations: amount-1 to 12 percent, size-fine or medium, contrast-faint to prominent, boundary-sharp or clear
Redox depletions: amount-0 to 12 percent, size-fine or medium, contrast-faint or distinct, boundary-clear or diffuse
EC (dS/m): 0 to 4
SAR: 0 to 8
Effervescence: none to slight
Reaction: slightly alkaline to strongly alkaline
COMPETING SERIES: There are no competing series in the same family. Similar soils are the
Edroy (TX),
Feterita (KS),
Hansford (TX),
Iberia (LA),
Randall (TX), and
Tiocano (TX) series.
Edroy soils: have smectitic clay mineralogy.
Feterita and Hansford soils: have a mesic temperature regime.
Iberia soils: have more than 60 percent clay in the particle-size control section.
Randall soils: have a thermic temperature regime.
Tiocano soils: are somewhat poorly drained and are more alkaline in the surface.
GEOGRAPHIC SETTING:
Parent material: clayey sediments of Pleistocene age
Landform: Concave depressions on the Lower Rio Grande Plains
Slope: 0 to 1 percent
Mean annual air temperature range: 22.2 to 23.4 degrees C (72 to 74 degrees F)
Mean annual precipitation range: 635 to 711 mm (25 to 28 inches)
Frost-free period: 320 to 350 days
Elevation: 1.5 to 12 meters (5 to 40 feet)
Thornthwaite annual P-E indices: 28 to 36
GEOGRAPHICALLY ASSOCIATED SOILS: These are the
Lozano,
Lyford,
Mercedes,
Palobia,
Racombes,
Raymondville,
Willacy, and
Yturria series.
Lozano and Lyford soils: have an argillic horizon and are on a higher, planar to slightly convex slopes.
Mercedes soils: are on slightly higher planar flats.
Palobia soils: have a natric horizon and occur on slightly higher planar to slightly convex slopes.
Racombes and Willacy soils: have an argillic horizon and occur on higher convex slopes.
Raymondville soils: have a calcic horizon within 100 cm of the surface and occur on a higher, planear to convex flat.
Yturria soils: have less than 18 percent clay in the particle-size control section and occur on convex blowout dunes.
DRAINAGE AND PERMEABILITY: Poorly drained. Permeability is very slow. Runoff is negligible. The soil is ponded from a few days to several weeks during the spring and fall seasons in normal years.
USE AND VEGETATION: These soils are mainly used for livestock grazing and wildlife habitat. Native vegetation consists of Hartweg's paspalum, brownseed paspalum, inland saltgrass, sedge and white tridens. The ecological site is Lakebed (083DY504TX).
DISTRIBUTION AND EXTENT: Lower Rio Grande Plain (MLRA 83D in LRR I) of extreme southern Texas. The series is of small extent.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Temple, Texas
SERIES ESTABLISHED: Kenedy County, Texas, 2007. The name is from a small town in Hidalgo County.
REMARKS: The series was formerly included in the Mercedes series and mapped as a ponded phase. Activity class and mineralogy based on a study conducted on the similar Mercedes soil sample P01TX061-001 and P01061-002. Although these soils have aquic conditions for short periods in most years, the g horizon suffix has not been used. These soils have low chroma colors that are presumed to be relict and related to parent material. Future study will verify the presence of gleying.
Diagnostic horizons and features recognized in this pedon are:
Particle size control section: 25 to 100 cm (10 to 40 in). (A2, Bss, Bkss1 Bkss2, and Bss3 horizons)
Mollic epipedon: 0 to 71 cm (0 to 28 in). (A1, A2 and Bss horizons)
Depth to redox concentrations: 0 to 203 cm (0 to 80 in). (A1, A2, Bss, Bkss1, Bkss2, Bkss3, BC1 and BC2 horizons)
Depth to redox depletions: 0 to 203 cm (0 to 80 in). (A1, A2, Bss, Bkss1, Bkss2, Bkss3, BC1 and BC2 horizons)
Vertic features: The presence of slickensides at 43 to 152 cm (17 to 59 in). (Bss, Bkss1, Bkss2 and Bkss3 horizons)
Ustic feature: have cracks 5 mm or wider in normal years, through a thickness of 25 cm or more, within 50 cm of the mineral soil surface for 90 or more cumulative days per year.
ADDITIONAL DATA: Particle-size analysis, salinity and sodicity tests by the soil survey project office lab.
TAXONOMIC VERSION: Keys to Soil Taxonomy, Tenth Edition, 2006.