LOCATION WILCO TXEstablished Series
TAXONOMIC CLASS: Fine, mixed, active, hyperthermic Typic Paleustalfs
TYPICAL PEDON: Wilco loamy fine sand--cultivated.
(Colors are for dry soil unless otherwise stated.)
Ap--0 to 6 inches; pale brown (10YR 6/3) loamy fine sand, brown (10YR 5/3) moist; structureless; loose, very friable; many fine roots; medium acid; clear smooth boundary. (4 to 8 inches thick)
A--6 to 16 inches; pale brown (10YR 6/3) loamy fine sand, brown (10YR 5/3) moist; structureless; soft, very friable; many fine roots; medium acid; abrupt wavy boundary. (6 to 12 inches thick)
Bt1--16 to 20 inches; brown (10YR 5/3) sandy clay, dark brown (10YR 4/3) moist; many medium and coarse distinct yellowish red (5YR 5/6) mottles; moderate fine blocky structure; very hard, very firm; few fine roots; few fine pores; common clay films on faces of peds; slightly acid; gradual wavy boundary. (3 to 10 inches thick)
Bt2--20 to 32 inches; brown (7.5YR 5/4) sandy clay, dark brown (7.5YR 4/4) moist; common fine and medium distinct yellowish red (5YR 5/6) and yellowish brown (10YR 5/4) mottles; moderate fine blocky structure; very hard, very firm; few fine roots; common clay films on faces of peds; neutral; gradual wavy boundary. (8 to 18 inches thick)
Bt3--32 to 38 inches; reddish yellow (7.5YR 6/6) sandy clay loam, strong brown (7.5YR 5/6) moist; many coarse distinct yellowish red (5YR 5/6) mottles; weak and moderate fine blocky structure; hard, firm; few fine roots; few clay films on faces of peds; neutral; gradual wavy boundary. (5 to 18 inches thick)
Bw--38 to 45 inches; light yellowish brown (10YR 6/4) fine sandy loam, yellowish brown (10YR 5/4) moist; few fine faint strong brown (7.5YR 5/6) mottles; weak medium blocky structure; hard, friable; mildly alkaline; clear smooth boundary. (5 to 15 inches thick)
BC--45 to 60 inches; very pale brown (10YR 7/3) fine sandy loam, pale brown (10YR 6/3) moist; structureless; slightly hard, friable; estimated 30 percent by volume of small fragments of gray (10YR 6/1) clayey shale; few fine weakly cemented calcium carbonate concretions; very slightly effervescent; moderately alkaline.
TYPE LOCATION: Wilson County, Texas; 5.5 miles west of intersection of Highways 181 and 97 in Floresville at a point 1/4 mile north of Highway 97 and 35 yards west of unpaved county road.
RANGE IN CHARACTERISTICS: Solum thickness ranges from 60 to more than 80 inches. Depth to secondary carbonates, in the form of films and threads or weakly cemented concretions comprising less than 5 percent of the matrix, ranges from 40 to 70 inches.
The A horizons have hue of 5YR to 10YR, value of 4 to 7 and chroma of 3 to 6. They are mainly loamy fine sand, but are fine sand in a few pedons. They are medium acid through neutral.
Colors of the Bt and Bw horizons range in hue from 2.5YR to 10YR, value of 4 to 7, and chroma of 4 to 6. Common to many, medium and coarse, distinct and prominent mottles of red, or yellowish red and faint to distinct mottles of strong brown, reddish yellow, yellowish brown, or light olive brown. The upper 20 inches of the Bt horizon are sandy clay, clay, or clay loam. Clay content of the upper 20 inches of the Bt horizon ranges from 35 to 48 percent clay. The Bt1 and Bt2 horizons range from medium acid through mildly alkaline and become more alkaline with depth. The Bt3 horizon is sandy clay loam or sandy clay. It is slightly acid through mildly alkaline. The Bw horizon is fine sandy loam or sandy clay loam and mildly or moderately alkaline and is calcareous in some pedons.
The BC horizon has the same color range as the Bt and Bw horizons. It is fine sandy loam or sandy clay loam. Most pedons contain thin strata of weakly consolidated sandstone and shale that are broken into small fragments in the upper part of the BC horizon. The BC horizon ranges from mildly to moderately alkaline.
COMPETING SERIES: These are the Floresville and Miguel series and the similar Devine and Webb series. Floresville soils have fine sandy loam A horizons, lack mottles in the Bt horizon, and have secondary forms of calcium carbonate between depths of 28 and 40 inches. Miguel soils have secondary forms of calcium carbonate at depths of 28 to 40 inches. Devine soils have more than 35 percent coarse fragments in the upper Bt horizon. Webb soils lack an abrupt texture change between the A and Bt horizon and are dry in the moisture control section for longer periods. Papalote soils have grayish colors in the upper Bt.
GEOGRAPHIC SETTING: Wilco soils occur on nearly level to sloping uplands. Slopes range from 0 to 8 percent. The soil formed in loamy materials several feet thick with thin strata of sandstone and shale. Average annual precipitation ranges from 26 to 32 inches and the Thornthwaite annual P-E index is from 36 to 44. The mean annual temperature ranges from 70 to 74 degrees F.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the competing Floresville and Miguel series and the Nueces and Sarita series. All these soils are on similar surfaces. Nueces and Sarita soils have sandy A horizons thicker than 20 inches and loamy Bt horizons.
DRAINAGE AND PERMEABILITY: Well drained; slow runoff; slow permeability.
USE AND VEGETATION: Used for dry and irrigated cropland, pasture, and rangeland. Main crops are peanuts, grain sorghums, corn, cotton, and watermelons. Pastures are mainly improved bermudagrass. Present native vegetation includes bristlegrass, windmillgrass, threeawn, mesquite, huisache, whitebrush, cacti, and annuals.
DISTRIBUTION AND EXTENT: Northern Rio Grande Plain of Texas. The series is of large extent with over 100,000 acres.
MLRA OFFICE RESPONSIBLE: Temple, Texas
SERIES ESTABLISHED: Wilson County, Texas; 1972.
REMARKS: Diagnostic horizons and features recognized in this pedon are:
Ochric epipedon - 0 to 16 inches.
Argillic horizon - 16 to 38 inches.