LOCATION DUVERT TXInactive Series
TAXONOMIC CLASS: Fine, smectitic, hyperthermic Sodic Haplusterts
TYPICAL PEDON: Duvert clay--in rangeland on a 2 percent convex west-facing slope. Elevation is 600 feet above sea level. (Colors are for dry soil unless otherwise stated.)
A--0 to 4 inches; grayish brown (2.5Y 5/2) clay, dark grayish brown (2.5Y 4/2) moist; moderate fine and medium subangular blocky structure parting to moderate fine angular blocky; very hard, very firm, very sticky and very plastic; common very fine and fine and few medium roots; few very fine and fine pores; slightly sodic; SAR 4.9; slightly effervescent; slightly alkaline; clear smooth boundary. (3 to7 inches thick)
Bnssz1--4 to 9 inches; light yellowish brown (2.5Y 6/3) clay, light olive brown (2.5Y 5/3) moist; moderate fine and medium angular blocky structure; few fine wedge-shaped aggregates; very hard, very firm, very sticky and very plastic; common very fine and fine and few medium roots; few very fine and fine pores; common distinct slickensides; 1 percent fine masses of salt; moderately sodic; SAR 16.8; violently effervescent; slightly effervescent; clear smooth boundary.
Bnssz2--9 to 20 inches; light yellowish brown (2.5Y 6/3) clay, light olive brown (2.5Y 5/3) moist; moderate fine and medium angular blocky structure; common wedge-shaped aggregates; very hard, very firm, very sticky and very plastic; common very fine and fine and few medium roots; few very fine pores; common distinct slickensides; 8 percent fine masses of salt; moderately sodic; SAR 27.8; violently effervescent; slightly alkaline; clear smooth boundary. (Combined thickness of the Bnssz horizon is 12 to 30 inches thick)
Bnssyz--20 to 38 inches; 65% pale olive (5Y 6/3) clay, olive (5Y 5/3) moist; 35% light yellowish brown (2.5Y 6/3) light olive brown (2.5Y 5/3) moist; moderate fine and medium angular blocky structure; common wedge-shaped aggregates; very hard, very firm, very sticky and very plastic; few very fine, fine, and medium roots; few very fine pores; few distinct slickensides; few fine pressure faces; 10 percent fine masses of salts; 8 percent fine and medium crystals of gypsum; moderately sodic; SAR 29.2; violently effervescent; slightly alkaline; clear smooth boundary. (6 to 24 inches thick)
Cryz--38 to 80 inches; pale olive (5Y 6/3) clay, olive (5Y 5/3) moist; massive; very hard, very firm, very sticky and very plastic; few fine and very fine roots along fractures; 5 percent fine and medium crystals of gypsum; moderately sodic; SAR 27.0; violently effervescent; moderately alkaline.
TYPE LOCATION: Duval County, Texas; from the intersection of Texas Highway 339 and Texas Highway 359 in Benavides, northwest 24.4 miles on Texas Highway 339 to Freer, southwest 2.9 miles on Texas Highway 59, west 8.7 miles on Texas Highway 44 to gate number 12, south 1.1 miles on private ranch road, east 1.0 mile on private ranch road, south 4.9 miles on field road, west 0.3 mile on field road; site is 50 feet north in rangeland. USGS Biel Lake SE, TX topographic quadrangle; Latitude: 27 degrees, 50 minutes, 42 seconds North; Longitude: 98 degrees, 46 minutes, 46 seconds West, NAD 1927.
RANGE IN CHARACTERISTICS:
Soil Moisture: An ustic moisture regime bordering on aridic. The soil moisture control section is dry in some or all parts for more than 220 days, but less than 260 days, cumulative, in normal years. There is a distinct increase in precipitation in the spring and fall. Winters and summers are dry.
Mean annual soil temperature: 72 to 76 degrees F.
Depth to paralithic contact: 20 to 40 inches
Clay content: 40 to 60 percent
Rock Fragments: 0 to 5 percent
A Horizon
Hue: 2.5Y or 10YR
Value: 5 or 6
Chroma: 2 to 4
Texture: clay
Clay content: 35 to 50 percent
Rock fragments: 0 to 5 percent
Base saturation: 90 to 100 percent
Calcium carbonate equivalent: 0 to 15 percent
EC (dS/m): 0 to 8
Gypsum: 0 to 5 percent
SAR: 0 to 13
Reaction: neutral to moderately alkaline
Bnssz Horizon
Hue: 5Y to 2.5Y
Value: 5 to 7
Chroma: 2 to 6
Texture: clay loam or clay
Clay content: 35 to 50 percent
Rock fragments: 0 to 5 percent
Base saturation: 90 to100 percent
Calcium carbonate equivalent: 0 to 15 percent
EC (dS/m): 8 to 20
Gypsum: 1 to 5 percent
SAR: 15 to 40
Reaction: slightly or moderately alkaline
Bnssyz Horizon
Hue: 5Y to 2.5Y
Value: 5 to 7
Chroma: 2 to 6
Texture: clay loam or clay
Clay content: 35 to 50 percent
Rock fragments: 0 to 5 percent
Base saturation: 90 to 100 percent
Calcium carbonate equivalent: 0 to 15 percent
EC (dS/m): 8 to 20
Gypsum: 2 to 15 percent
SAR: 15 to 40
Reaction: slightly alkaline or moderately alkaline
Cryz Horizon
Hue: 5Y to 2.5Y
Value: 5 to 7
Chroma: 2 to 6
Texture: soft shale with texture of clay
Clay content: 40 to 60 percent
Rock fragments: 0 to 5 percent
Base saturation: 90 to 100 percent
Calcium carbonate equivalent: 0 to 15 percent
EC (dS/m): 8 to 20
Gypsum: 2 to 15 percent
SAR: 15 to 40
Reaction: neutral to moderately alkaline
COMPETING SERIES: These are the
Cotulla (TX),
Lasalle (TX), and
Montell (TX) series.
Cotulla, Lasalle, and Montell soils: have sola greater than 60 inches. In addition, Lasalle soils have hue of 10YR or redder in the B horizons.
GEOGRAPHIC SETTING:
Parent material: Residuum derived from Cretaceous and Tertiary shale.
Landform: Upland
Mean annual temperature: 70 to 73 degrees F.
Mean annual precipitation: 22 to 26 inches
Frost-free period: 270 to 320 days
Elevation: 400 to 700 feet
GEOGRAPHICALLY ASSOCIATED SOILS: These are the Brundage (TX), Catarina (TX), Montell (TX), and Verick (TX) soils.
Brundage,
Catarina,
Montell soils: all have sola greater than 80 inches. In addition, Brundage soils have a natric horizon and are in the fine-loamy family. These soils occur on lower positions in the landscape.
Verick soils: are shallow to sandstone and occur on slightly higher positions in the landscape.
DRAINAGE AND PERMEABILITY: Well drained; very slow permeability; runoff is very high.
USE AND VEGETATION: Used primarily as rangeland and wildlife habitat. The grasses consist primarily of buffalograss, sideoats grama, curlymesquite, hairy tridens, tobosa, red grama, and threeawn. Woody vegetation is mostly mesquite, blackbrush, guayacan, and huisache.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Temple, Texas
DISTRIBUTION AND EXTENT: Central Rio Grande Plain, Texas; LRR I; MLRA 83C; the series is of minor extent.
SERIES PROPOSED: Duval County, Texas, 1999. The name is coined.
REMARKS: The series was previously included in the Maverick series. Duvert soils are moist in the SMCS for slightly longer periods of time.
Diagnostic horizons and features recognized in this pedon are:
Particle size control section: The zone from 10 to 40 inches. (Bssz2, Bnssyz and Cryz horizons)
Ochric epipedon: 0 to 4 inches. (A horizon)
Vertic features: The presence of slickensides at 4 to 38 inches. (Bnssz1, Bnssz2, and Bnssyz horizons)
TAXONOMIC VERSION: Keys to Soil Taxonomy, Eighth Edition, 1998