LOCATION SUNEV TXEstablished Series
TAXONOMIC CLASS: Fine-loamy, carbonatic, thermic Udic
Calciustolls
TYPICAL PEDON: Sunev loam--cropland. (Colors are for dry soil unless otherwise stated.)
Ap--0 to 6 inches; dark grayish brown (10YR 4/2) loam, very dark grayish brown (10YR 3/2) moist; thin light brownish gray surface crust; moderate fine and medium granular structure; hard, friable; common wormcasts; few fine fragments of snail shells; calcareous; moderately alkaline; abrupt smooth boundary. (5 to 10 inches thick)
A--6 to 12 inches; dark grayish brown (10YR 4/2) loam, very dark grayish brown (10YR 3/2) moist; strong fine and medium granular structure; hard, friable; common wormcasts and holes; common fine fragments of snail shells; few films of calcium carbonate; calcium carbonate equivalent about 35 percent; calcareous; moderately alkaline; gradual smooth boundary. (4 to 14 inches thick)
Bk1--12 to 21 inches; brown (10YR 5/3) loam, dark brown (10YR 4/3) moist; strong medium granular and very fine subangular blocky structure; hard, friable; common wormcasts and holes; many films and threads of calcium carbonate; few fine fragments of snail shells; calcium carbonate equivalent about 50 percent; calcareous; moderately alkaline; gradual smooth boundary. (9 to 36 inches thick)
Bk2--21 to 60 inches; very pale brown (10YR 7/4) loam, light yellowish brown (10YR 6/4) moist; strong very fine and fine granular structure; slightly hard, very friable; few wormcasts and holes; many films and threads of calcium carbonate; few fine fragments of snail shells; calcium carbonate equivalent about 65 percent; calcareous; moderately alkaline; diffuse smooth boundary. (0 to 44 inches thick)
Bk3--60 to 72 inches; very pale brown (10YR 7/4) loam, light yellowish brown (10YR 6/4) moist; moderate fine and medium subangular blocky structure; slightly hard, very friable; many films and threads of calcium carbonate; few fine fragments of snail shells; calcium carbonate equivalent about 65 percent; calcareous; moderately alkaline.
TYPE LOCATION: Guadalupe County, Texas; 4 miles northwest of McQueeney on Farm Road 725; 0.8 mile east on gravel road; 300 feet south into field.
RANGE IN CHARACTERISTICS: Solum thickness ranges from 40 to 70 inches. Calcium carbonate equivalent in the 10- to 40-inch control section ranges from 40 to 70 percent. Fine fragments of snail shells are in all horizons. Films and threads of calcium carbonate are evident in all horizons and increase with depth. The silicate clay content ranges from 18 to 35 percent and carbonate clay from 2 to 10 percent. Siliceous and limestone pebble content ranges from 0 to 15 percent.
The A horizon has color with hue of 10YR, value of 3 to 5 and chroma of 2 or 3. It is fine sandy loam, loam, clay loam, or silty clay loam.
The Bk horizons have color with hue of 10YR, value of 4 to 7, and chroma of 2 to 4; hue of 7.5YR, value of 4 to 7, and chroma of 4 or 6; or hue of 5YR, value of 5, and chroma of 4. In some pedons, these horizons contain few to common brownish and yellowish mottles. Texture is loam, clay loam, or silty clay loam. In some pedons the lower part of the horizon contains up to 50 percent by volume of limestone pebbles and calcium carbonate concretions. Weakly cemented limestone occurs below 40 inches in some pedons.
COMPETING SERIES: These include Bolar, Carbengle, Rumley, and Topsey series in the same family and the similar Lewisville, Nuvalde, Oakalla, Seawillow, and Venus series. Bolar soils have a lithic contact with limestone at depths of 20 to 40 inches. Carbengle soils have a paralithic contact with sandstone at depths of 20 to 40 inches. Rumley soils contain less finely divided lime and more concretions of calcium carbonate in the upper Bk, and have a more distinct and contrasting calcic horizon. Topsey soils have sola less than 40 inches thick over shaly and marly sediments. Lewisville, Nuvalde, and Venus soils have calcium carbonate equivalents less than 40 percent in the 10- to 40-inch control section. Oakalla soils have mollic epipedons more than 20 inches thick and have an irregular distribution of organic matter in a vertical section. Seawillow soils do not have mollic epipedons.
GEOGRAPHIC SETTING: Sunev soils are on low stream terraces or colluvial foot slopes. Slope gradients range from 0 to 15 percent. The soil formed in loamy alluvial sediments that are high in calcium carbonate. Climate is dry subhumid. Mean annual rainfall ranges from 28 to 34 inches. Mean annual temperature ranges from 62 to 69 degrees F. Thornthwaite P-E indices range from 40 to 56.
GEOGRAPHICALLY ASSOCIATED SOILS: These include the competing Lewisville, and Rumley series and Altoga, Bosque, and Karnes, Seguin, and Venus series. Lewisville and Rumley are on slightly higher positions. Altoga and Karnes soils have ochric epipedons. In addition, Altoga soils have fine-silty control sections and are on higher positions. Karnes soils have coarse-loamy control sections and are on similar positions. Bosque and Sequin soils are on flood plains and have thicker mollic epipedons. Venus soils contain less than 40 percent calcium carbonate equivalent and are on nearby areas.
DRAINAGE AND PERMEABILITY: Well drained; slow to medium runoff; moderate permeability.
USE AND VEGETATION: Mostly cropped to cotton, grain sorghums, and oats. Native vegetation is mainly big bluestem, little bluestem, switchgrass, and indiangrass, with scattered hackberry and pecan trees.
DISTRIBUTION AND EXTENT: Central Texas, along stream terraces draining the Edwards Plateau. The soils are of minor extent.
MLRA OFFICE RESPONSIBLE: Temple, Texas
SERIES ESTABLISHED: Guadalupe County, Texas; 1973.
REMARKS: These soils were formerly included with the Venus series.
Classification was changed 11/89 from Typic Calciustolls to Udic Calciustolls.
Diagnostic horizons and features recognized in this pedon are:
Mollic epipedon - 0 to 12 inches.
Calcic horizon - 12 to 60 inches.