LOCATION ODEM TXEstablished Series
TAXONOMIC CLASS: Coarse-loamy, mixed, superactive, hyperthermic Cumulic Haplustolls
TYPICAL PEDON: Odem fine sandy loam--rangeland.
Colors are for dry soil unless otherwise stated.)
A--0 to 16 inches; dark gray (10YR 4/1) fine sandy loam, very dark gray (10YR 3/1) moist; weak fine and very fine granular structure; slightly hard, friable; many fine roots; many fine and medium pores; neutral; diffuse smooth boundary. (5 to 24 inches thick)
Bw1--16 to 40 inches; dark gray (10YR 4/1) fine sandy loam, dark gray (10YR 3/1) moist; moderate coarse prismatic structure parting to weak fine subangular blocky; slightly hard; friable; few fine roots; few fine and medium pores; slightly alkaline; gradual smooth boundary. (10 to 30 inches thick)
Bw2--40 to 80 inches; grayish brown (10YR 5/2) fine sandy loam, dark grayish brown (10YR 4/2) moist; massive; slightly hard, friable; few thin strata and bedding planes of loamy fine sand mainly in the lower part; few fine pores; strongly effervescent; moderately alkaline.
TYPE LOCATION: San Patricio County, Texas.; from the intersection of U.S. Highway 181 and U.S. Highway 77 in Sinton; 7.3 miles north on U.S. Highway 77 to entrance of Rob and Bessie Welder Wildlife Refuge; 1.7 miles east on entrance road to intersection; 1.6 miles south and east on paved ranch road to Y intersection; left and northeast 0.9 miles to intersection; northwest and north 0.4 mile on gravel road past windmill to intersection; 400 feet west and 50 feet south in rangeland. This point is about 0.5 mile west of Venado Tank, and 0.3 mile south of Aransas River. (Latitude 28N, 07,34; Longitude 97W, 22, 30)
RANGE IN CHARACTERISTICS: Solum thickness ranges from 60 to more than 80 inches. Thickness of the mollic epipedon ranges from 20 to 55 inches. Clay content of the 10 to 40 inch particle-size control section ranges from 10 to 18 percent.
The A horizon has hue of 10YR, value of 3 to 5, and chroma 1 to 3. Texture is fine sandy loam or loam. Reaction ranges from slightly acid to moderately alkaline. Some pedons are calcareous.
The Bw1 horizon has hue of 10YR, value of 3 to 5, and chroma 1 to 3. Texture is fine sandy loam or loam. Reaction ranges from neutral to moderately alkaline.
The Bw2 horizon has hue of 10YR, value of 4 to 7, and chroma of 1 to 3. Some pedons are faintly stratified with individual strata that range from sandy clay loam to sand, but have a average texture of fine sandy loam or loam. Reaction ranges from neutral to moderately alkaline.
Some pedons have C horizons that are distinctly stratified with similar color and textures as the Bw2 horizon. Individual strata range from sandy clay loam to fine sand. Reaction ranges from neutral to moderately alkaline.
COMPETING SERIES: There are no other series in this family. Similar soils include the Bosque, Cyril, Degola, Ramadero, and Sinton series. Bosque and Cyril soils have mean annual soil temperatures of less than 72 degrees F. In addition, Bosque soils as well as Degola, Ramadero, and Sinton soils have more than 18 percent clay in their particle-size control section.
GEOGRAPHIC SETTING: Odem soils are on convex, nearly level to gently undulating natural levees or low terraces in bottomlands between the main stream channels and back water areas that are adjacent to the uplands. Slopes are generally less than 1 percent but range up to about 3 percent. These soils are inundated with floodwaters on the average of 1 to 8 times in 20 years or more. The soil formed in Recent loamy alluvial sediments. Mean annual precipitation ranges from 23 to 35 inches. Mean annual air temperature ranges from about 70 to 73 degrees F. Frost free days range from 275 to 300. Elevation ranges from 50 to 300 feet. Thornthwaite PE indices range from 31 to 44.
GEOGRAPHICALLY ASSOCIATED SOILS: These include the competing Sinton series and the Aransas series. Aransas soils have a clayey particle-size control section. Aransas and Sinton soils occur on similar to slightly lower elevations.
DRAINAGE AND PERMEABILITY: Well drained. Permeability is moderately rapid. Runoff is negligible.
USE AND VEGETATION: Used for cropland, improved pastures, and rangeland. Cotton, grain sorghum, and corn are the main crops grown. Native vegetation consists of occasional hackberry and anacua trees, few scattered invading mesquite and huisache trees. Range grasses are seacoast bluestem, balsamscale, sideoats grama, knotroot panicum, and threeawn.
DISTRIBUTION AND EXTENT: Rio Grande Plain (MLRA 83A) and Gulf Coast Prairies (MLRA 150A) of Texas. The series is of moderate extent.
MLRA OFFICE RESPONSIBLE: Temple, Texas
SERIES ESTABLISHED: San Patricio County, Texas; 1971.
REMARKS: These soils were previously included with the Zavala series.
Diagnostic horizons and features in this pedon are:
Mollic epipedon - the zone from the surface of the soil to a depth of approximately 40 inches. (A, Bw1 horizons)