LOCATION PONTOTOC TXEstablished Series
TAXONOMIC CLASS: Coarse-loamy, mixed, active, thermic Rhodic Paleustalfs
TYPICAL PEDON: Pontotoc fine sandy loam--cultivated. (Colors are for dry soil unless otherwise stated.)
Ap--0 to 5 inches; dark reddish brown (2.5YR 3/4) fine sandy loam, dark reddish brown (2.5YR 3/4) moist; weak fine granular structure; slightly hard, very friable; slightly acid; abrupt smooth boundary. (4 to 6 inches thick)
A--5 to 10 inches; dark reddish brown (2.5YR 3/4) fine sandy loam, dark reddish brown (2.5YR 3/4) moist; weak fine granular and subangular blocky structure; slightly hard, very friable; few roots; common fine and medium pores; slightly acid; diffuse smooth boundary. (3 to 8 inches thick)
Bt1--10 to 21 inches; dark reddish brown (2.5YR 3/4) fine sandy loam, dark reddish brown (2.5YR 3/4) moist; weak fine subangular blocky structure; slightly hard, very friable; few roots; few fine and medium pores; few patchy clay films; slightly acid; diffuse smooth boundary. (5 to 14 inches thick)
Bt2--21 to 33 inches; dark red (2.5YR 3/6) fine sandy loam, dark red (2.5YR 3/6) moist; weak fine subangular blocky structure; hard, friable; few roots; common fine and medium pores; clay films in pores; slightly acid; diffuse smooth boundary. (5 to 14 inches thick)
Bt3--33 to 67 inches; dark red (2.5YR 3/6) sandy clay loam, dark red (2.5YR 3/6) moist; weak fine subangular blocky structure; hard, friable; few fine pores; patchy clay films in pores; few roots; slightly acid; clear irregular boundary. (18 to 45 inches thick)
Cr--67 to 70 inches; red weakly cemented sandstone bedrock.
TYPE LOCATION: Mason County, Texas. About 1 mile west of Mason, Texas. From the court house in Mason 0.8 mile north on U.S. Highway 87, 0.6 mile west and northwest on county road, 0.4 mile west on private road to field boundary, 350 yards west in cultivated field.
RANGE IN CHARACTERISTICS: Solum thickness is 60 to 80 inches over sandstone. Sandstone cobbles and pebbles range from 0 to about 10 percent throughout. The reaction is slightly acid or neutral.
The A horizon has hue of 2.5YR or 5YR, value of 3 or 4, and chroma of 3 to 6. Clay content is 8 to 15 percent.
The Bt1 horizon has a hue of 10R or 2.5YR, value of 3 or 4, and chroma of 4 through 6. Texture is fine sandy loam with a clay content of 12 to 18 percent.
The lower Bt horizons have hue of 10R or 2.5YR, value of 3 or 4, and chroma of 6. Texture is fine sandy loam or sandy clay loam with a clay content of 18 to 22 percent.
The Cr horizon is weakly to strongly cemented reddish sandstone bedrock with a hardness of 2 to 3 on Mohs scale. The sandstone usually contains some glauconite.
COMPETING SERIES: There are no other soils in this family. Similar soils include the Cobb, Duval and Springer series. Cobb soils have fine-loamy control sections and are less than 40 inches thick. Devol and Springer soils have hue of 5YR or browner and lack sandstone within 80 inches.
GEOGRAPHIC SETTING: Pontotoc soils are on erosional uplands, and slope gradients range from 0 to about 8 percent. The soil formed over the Hickory Sandstone. The climate is dry subhumid. Average annual precipitation is 24 to 28 inches, mean annual temperature is 65 degrees to 67 degrees F., Frost free period is 215 to 235 days, and elevation ranges from 1,000 to 1,900 feet. Thornthwaite annual P-E index is 38 to 44.
GEOGRAPHICALLY ASSOCIATED SOILS: These include Hye, Nebgen, Oben and Yates series. Hye and Oben soils are on similar positions. Hye soils have fine-loamy control section and Oben soils are less than 20 inches thick over sandstone bedrock. Nebgen and Yates soils are on higher associated ridges. Both soils are shallow to bedrock.
DRAINAGE AND PERMEABILITY: Well drained, slow to medium runoff, moderate permeability.
USE AND VEGETATION: Used for dray and irrigated cropland and for rangeland. Crops are mostly grain sorghum, peanuts, and vegetables. Considerable acreage is used for irrigated tame pastures. Rangeland vegetation is mostly hooded windmill grass, purple three-awn, sand dropseed, sandbur grasses, and a few live oak, post oak, mesquite, whitebrush, and tasajillo.
DISTRIBUTION AND EXTENT: Mostly in the Central Basin of Texas. The series is of moderate extent.
MLRA OFFICE RESPONSIBLE: Temple, Texas
SERIES ESTABLISHED: Recon. Soil Survey of South Central Texas - 1913.
REMARKS:
Diagnostic horizon and features recognized in this pedon are:
Ochric epipedon --0 to 10 inches
Argillic horizon --10 to 67 inches
Paralithic contact at 67 inches.