LOCATION VERNON TX+KS+OKEstablished Series
The Vernon series consists of moderately deep over claystone bedrock, well drained, very slowly permeable soils that formed in residuum over noncemented claystone bedrock or dense clay of Permian age. These soils are on gently sloping to steep plains and escarpments of the Central Rolling Red Plains (MLRA-78B, 78C), Central Limestone Prairies (MLRA 78D) and North Central Prairie (MLRA 80B). Slopes range from 1 to 45 percent.
TAXONOMIC CLASS: Fine, mixed, active, thermic Typic Haplustepts
TYPICAL PEDON: Vernon clay--rangeland. (Colors are for dry soil unless otherwise stated.)
A--0 to 5 inches; red (2.5YR 4/6) clay, dark red (2.5YR 3/6) moist; moderate fine subangular blocky structure; very hard, firm, very sticky, plastic; many fine and common medium roots; few fine and medium concretions of calcium carbonate; violently effervescent; moderately alkaline; clear smooth boundary. (3 to 12 inches thick)
Bk--5 to 25 inches; dark red (2.5YR 3/6) clay, dark red (2.5YR 3/6) moist; moderate fine and medium subangular blocky structure; very hard, firm, very sticky, plastic; common fine and medium roots; common medium concretions of calcium carbonate; common pressure faces; violently effervescent; moderately alkaline; clear smooth boundary. (11 to 28 inches thick)
Cd1--25 to 63 inches; red (2.5YR 4/6) noncemented claystone bedrock, red (2.5 4/6) moist; massive with weak very thin platy and fine angular blocky rock structure; very hard, very firm, sticky, plastic; few fine roots along fractures; few masses of light greenish gray (5GY 7/1) claystone; strongly effervescent; moderately alkaline; gradual smooth boundary. (0 to 40 inches thick)
Cd2--63 to 80 inches; red (2.5YR 4/6) noncemented claystone bedrock, red (2.5YR 4/6) moist; massive with moderate coarse angular rock structure parting to fine angular rock structure; extremely hard, extremely firm, very sticky, plastic; few masses of light greenish gray (5GY 7/1) claystone; slightly effervescent; moderately alkaline; gradual smooth boundary. (0 to 17 inches thick)
TYPE LOCATION: Wilbarger County, Texas; from the intersection of U.S. Highways 183 and 283 and Texas Farm to Market Road 1763 which is about 12.5 miles south-southeast of Vernon; 3.22 miles south-southeast on U.S. Highway 183 & 283 (1.82 mile south-southeast of Beaver Creek); 1,430 feet southeast and east on oil field road; 75 feet south in rangeland. (Texas Coordinate System Grid: 829,850 feet N, 1,484700 feet E); USGS Grayback Quadrangle; (Latitude 33N, 56, 10; Longitude 99W, 11, 56).
RANGE IN CHARACTERISTICS: Solum thickness and depth to densic material ranges from 20 to 40 inches and corresponds to depth to redbed claystone bedrock or dense clay. Depth to a densic contact is more than 30 inches. Typically, the soil is effervescent throughout, but some pedons are noneffervescent in the upper few inches. Caliche and sandstone pebbles range from none to common on the surface layer. Some pedons have sandstone or limestone boulders on the surface layer. They range from 2 to 20 feet across the long axis and are about 1 to 5 feet thick. These fragments cover about 2 to 25 percent of the surface in some soil areas.
The A horizon has hue of 2.5YR to 7.5YR, value of 4 or 5, and chroma of 2 to 6. The texture is clay loam, silty clay loam, silty clay, or clay.
The Bk or Bw horizon has hue of 10R to 5YR, value of 4 or 5, and chroma of 3 to 6. Texture is silty clay or clay with clay content of 40 to 60 percent. Concretions, masses, films, and threads of calcium carbonate range from few to about 10 percent by volume. Calcium carbonate equivalent ranges from 5 to 20 percent.
The Cd1 layer has colors in shades of red or reddish brown. Texture is clay, clay with claystone fragments, or claystone bedrock. Fractures that roots can enter range are less than 10 cm apart and bulk density is high enough to be root restrictive. Some pedons contain claystone fragments in shades of gray or olive yellow. Concretions, masses, or films of calcium carbonates range from none to about 5 percent by volume mainly in the upper part along cleavage planes or fractures. Excavation difficulty is low to moderate. Moist bulk density is 1.70 or higher.
The Cd2 layer has colors mainly in shades of red or gray. It is weathered claystone bedrock that is moderately to highly fractured. This material is densic with rock structure. Fractures that roots can enter range are 10 cm or more apart and bulk density is high enough to be root restrictive. Some pedons contain thin discontinuous strata of limestone or sandstone. It is typically effervescent but interiors of fragments range to noneffervescent. Excavation difficulty is low to high and material slakes in minutes. The moist bulk density is about 1.85 to 2.35. In some pedons, the CD2 is at depth of more than 80 inches.
COMPETING SERIES: These are the Owens series in the same family. Similar soils are the Aspermont, Knoco, Obaro, Stamford, Throck, and Tilvern soils. Owens and Throck soils have hue yellower than 5YR. Aspermont, and Obaro soils have a particle-size control section with less than 35 percent clay. Knoco soils have sola less than 20 inches thick. Stamford soils have slickensides and smectitic mineralogy. Tilvern soils have vertic properties and sola 40 to 60 inches thick.
GEOGRAPHIC SETTING: Vernon soils are on broad gently sloping to steep plains and escarpments. Slope gradients are mainly 1 to 12 percent but range from about 1 to 45 percent. The soil formed in clayey material weathered from redbed claystone of Permian age. Mean annual precipitation ranges from 20 to 30 inches, and the mean annual temperature from 57 to 65 degrees F. Frost-free days range from 190 to 230 days, and elevation ranges from 1,000 to 2,500 feet. The Thornthwaite P-E indices ranges from 32 to 46.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the Aspermont, Burford, Hollister, Knoco, Obaro, Owens, Stamford, Tillman, Tilvern, Westill, and Weymouth soils. Aspermont, Burford, Obaro, and Weymouth soils have a particle-size control section with less than 35 percent clay and are on similar positions as the Vernon series. Knoco and Owens soils have sola less than 20 inches thick and are on slightly higher landscapes. Hollister and Stamford soils have smectitic mineralogy and are commonly on lower, flatter slopes. Tillman and Westill soils are on slightly flatter slopes and have a mollic epipedon. Tilvern soils have sola 40 to 60 inches thick and are on similar landscapes.
DRAINAGE AND PERMEABILITY: Well drained. Permeability is very slow. Runoff is very high.
USE AND VEGETATION: Used mainly for rangeland. Typical native grasses, include sideoats grama, buffalograss, silver bluestem, blue grama, vine mesquite, Texas wintergrass, slim tridens, threeawn, and other perennial grasses and forbs. A small percentage of the acreage is cultivated with cotton, grain sorghums, and small grains the main crops.
DISTRIBUTION AND EXTENT: Central Rolling Red Plains, (MLRA 78B, 78C), Rolling Limestone Prairie (MLRA-78D) and North Central Prairie (MLRA-80B) of Texas, Kansas and Oklahoma. The series is extensive.
MLRA OFFICE RESPONSIBLE: Temple, Texas
SERIES ESTABLISHED: Wilbarger County, Texas; 1902.
REMARKS: Diagnostic horizons and features recognized in this pedon are:
Ochric epipedon - 0 to 5 inches. (A horizon)
Densic material - the zone from 25 to 80 inches.
Densic Contact - at 63 inches (top of the Cd2 layer).
Soil Interpretation Record: TX0249 series, TX1094 bouldery, and TX1024 overblown.
Range Site: Clay Prairie - 078CY112TX or 078BY090TX
ADDITIONAL DATA: National Soil Survey Laboratory data 823146-823157 (Haskell Co.), 79963-79969 (Stephens Co.)
TAXONOMIC VERSION: Soil Taxonomy, Second Edition, 1999.