LOCATION COY TXEstablished Series
TAXONOMIC CLASS: Fine, smectitic, hyperthermic Vertic Argiustolls
TYPICAL PEDON: Coy clay loam--cropland.
(Colors are for dry soil unless otherwise stated.)
Ap--0 to 6 inches; dark gray (10YR 4/1) clay loam, very dark gray (10YR 3/1) moist; weak fine granular and subangular blocky structure; hard, firm; many fine roots; common wormcasts and insect tunnels; 1/8 inch gray (10YR 6/1) surface crust; very slightly effervescent; moderately alkaline; clear smooth boundary. (4 to 11 inches thick)
Bt1--6 to 12 inches; dark gray (10YR 4/1) clay loam, very dark gray (10YR 3/1) moist; weak coarse prismatic structure parting to moderate fine subangular blocky; hard, firm; many fine roots; many wormcasts and insect tunnels; few clay films on surface of peds; slightly effervescent; moderately alkaline; gradual wavy boundary.
Bt2--12 to 25 inches; dark gray (10YR 4/1) clay, very dark gray (10YR 3/1) moist; weak medium prismatic structure parting to moderate fine blocky; very hard, firm; common fine roots; common wormcasts and insect tunnels; common pressure faces; few clay films on surface of peds; slightly effervescent; moderately alkaline; gradual wavy boundary.
Bt3--25 to 40 inches; dark grayish brown (10YR 4/2) clay, very dark grayish brown (10YR 3/2) moist; moderate fine and medium blocky structure; very hard, firm; common pressure faces; few clay films on surface of peds; few fine and very fine concretions of calcium carbonate; strongly effervescent; moderately alkaline; gradual wavy boundary. (Combined thickness of Bt horizons is 20 to 50 inches)
Bk--40 to 55 inches; brown (10YR 5/3) clay, dark brown (10YR 4/3) moist; moderate medium blocky structure; very hard, firm; few dark grayish brown (10YR 4/2) vertical streaks to 1/4 inch wide that are apparently filled cracks; common pressure faces; common masses and fine concretions of calcium carbonate; strongly effervescent; moderately alkaline; gradual wavy boundary. (10 to 20 inches thick)
BCky--55 to 80 inches; mottled grayish brown (10YR 5/2) and brownish yellow (10YR 6/6) clay, dark grayish brown (10YR 4/2) and yellowish brown (10YR 5/6) moist; weak medium blocky structure; very hard, firm; few dark grayish brown vertical streaks; few fine concretions of calcium carbonate; few to common crystals of gypsum; few fragments of shale; strongly effervescent; moderately alkaline.
TYPE LOCATION: Wilson County, Texas; from the intersection of U. S. Highway 181 and Texas Highway 97 in Floresville; 4.5 miles south on U. S. Highway 181; 300 feet north of petroleum service station; 150 feet east in cultivated field.
RANGE IN CHARACTERISTICS: Solum thickness ranges from 60 to more than 80 inches. When dry, the soil has cracks up to 2 inches wide at the surface that extend to depths of more than 40 inches. Thickness of the mollic epipedon ranges from 12 to 45 inches. The amplitude of waviness of the lower boundary ranges from about 10 to 20 inches within a horizontal distance of 6 to 26 feet. Reaction is moderately alkaline throughout.
The A horizon has hue of 10YR, value of 2 to 4, and chroma of 1 or 2. Texture is sandy clay loam, clay loam, or clay. Clay content ranges from 25 to 45 percent and silt content 25 to 35 percent.
Some pedons have a BA horizon that has the same color and texture range as the A horizon.
The Bt horizons have hue of 10YR, value of 3 to 6, and chroma of 1 to 4. Texture is clay loam, sandy clay, or clay. Clay content ranges from 35 to 60 percent. Calcium carbonate content, mostly in the form of masses and concretions, ranges from 0 to 3 percent by volume.
Some pedons have Btk horizons that have the same color and textures as the Bt horizon. Calcium carboate content, mostly in the form or masses, threads, and concretions, ranges from 3 to 10 percent by volume.
The Bk or Bky horizons have hue of 10YR, value of 5 to 7, and chroma of 2 to 6. Calcium carbonate, in the form of masses or concretions, ranges from 10 to 20 percent by volume. Gypsum content ranges form 0 to 5 percent by volume.
The BC horizon is mottled in various shades of brown, gray or yellow in hue of 10YR or 2.5Y. Texture is silty clay or clay. Calcium carbonate content, mainly in the form of masses, films, or concretions, ranges from 1 to 15 percent by volume. Gypsum content ranges from 0 to 10 percent by volume with visible threads and films ranging from 0 to 5 percent.
Some pedons have C horizons that is weakly consolidated siltstone of clay or silty clay texture below 60 inches.
COMPETING SERIES: These include the Elmendorf series. Similar soils are the Clareville, Durant, Marcelinas, Monteola, Olmito, Raymondville, Topia, and Tordia series. Elmendorf and Marcelinas soils are noncalcareous in the A and upper Bt horizons and, in addition, Marcelinas soils have hue redder than 10YR in some part. Clareville soils do not have vertic properties. Durant and Topia soils have soil temperatures of less than 72 degrees F. Monteola soils have slickensides. Olmito and Tordia soils do not have an argillic horizon. Raymondville soils have calcic horizons at a depth of less than 40 inches.
GEOGRAPHIC SETTING: Coy soils are on nearly level to gently sloping uplands. Slope gradients range from 0 to 5 percent but are dominantly 1 to 3 percent. The soil formed in calcareous clayey shales. Mean annual precipitation ranges from 26 to 32 inches. Mean annual temperature ranges from 70 to 73 degrees F. Frost free days range from 275 to 295 days and elevation ranges from 250 to 500 feet. Thornthwaite P-E index ranges from 31 to 44.
GEOGRAPHICALLY ASSOCIATED SOILS: These include the competing Clareville, Elmendorf, Marcelinas, Monteola, and Tordia series and the Floresville and Orelia series. Floresville soils are at higher elevation and have hue redder than 10YR. Orelia soils are at lower elevations with less slope and have less than 35 percent clay in the Bt horizon.
DRAINAGE AND PERMEABILITY: Well drained. Permeability is very slow. Runoff is low on 0 to 1 percent slopes, medium on 1 to 3 percent slopes, and high on 3 to 5 percent slopes.
USE AND VEGETATION: Mostly cultivated. Main crops are grain sorghum, cotton, corn, and small grains. Pastures are mainly improved bermudagrass.
DISTRIBUTION AND EXTENT: Northern Rio Grande Plain of Texas (MLRA 83A). The series is of moderate extent.
MLRA OFFICE RESPONSIBLE: Temple, Texas
SERIES ESTABLISHED: Wilson County, Texas; 1972.
REMARKS: The Coy soils were formerly included with the Monteola series.
Diagnostic horizons and features recognized in this pedon are:
Mollic epipedon - 0 to 40 inches. (A and Bt horizons)
Argillic horizon - 6 to 40 inches. (Bt horizons)
Calcic horizons - from 40 to 55 inches. (Bk horizon)
SOIL INTERPRETATION RECORD NO: TX0078