LOCATION ROWENA TXEstablished Series
TAXONOMIC CLASS: Fine, mixed, superactive, thermic Vertic Calciustolls
TYPICAL PEDON: Rowena clay loam--cropland. (Colors are for dry soil unless otherwise stated.)
Ap--0 to 5 inches; dark grayish brown (10YR 4/2) clay loam, very dark grayish brown (10YR 3/2) moist; weak subangular blocky and granular structure; firm; hard; thin surface crust; strongly effervescent; moderately alkaline; abrupt smooth boundary. (4 to 10 inches thick)
A--5 to 9 inches, dark grayish brown (10YR 4/2) clay loam, very dark grayish brown (10YR 3/2) when moist; weak subangular blocky structure; firm when moist, very hard when dry; few very small tubes; strongly effervescent; moderately alkaline; clear smooth boundary. (0 to 8 inches thick)
Bw1--9 to 18 inches, brown (10YR 4/3) clay loam, dark brown (10YR 3/3) when moist; moderate, fine and very fine, subangular blocky and angular blocky structure; firm very hard; few very fine tubes or pores few limestone fragments 1/16 to 1/8 inch in diameter; strongly effervescent; moderately alkaline; clear wavy boundary that has a maximum of 7 inches between highs and lows. (6 to 12 inches thick)
Bw2--18 to 34 inches, brown (7.5YR 5/3) clay, brown (7.5YR 4/3) moist; moderate, fine and medium angular blocky structure; firm extremely hard; few fine tubes or pores; few burrows; few limestone fragments 1/16 to 1/8 inch in diameter; shiny pressure faces on ped surfaces; strongly effervescent; moderately alkaline gradual wavy boundary that has a maximum difference of 12 inches between the highs and lows over a distance of 36 inches. (12-22 inches thick)
Bk--34 to 49 inches, pink (7.5YR 8/3) silty clay loam, reddish yellow (7.5YR 6/6) moist; weak medium and coarse subangular blocky structure; firm, very hard; few weakly and strongly cemented calcium carbonate concretions 1/8 inch to 1 1/2 inches in diameter; 35 percent soft masses of calcium carbonate; violently effervescent; moderately alkaline; gradual smooth boundary. (14 to 30 inches thick)
BCk--49 to 60 inches, pink (7.5YR 7/4) clay loam, strong brown (7.5YR 5/6) moist; weak medium and coarse subangular blocky structure; firm hard; few tubes and earth-worm casts; 15 percent of soil mass is visible calcium carbonate; violently effervescent; moderately alkaline.
TYPE LOCATION: Runnels County, Texas; From the junction of U.S. Highway 67 and Farm Road 2406 in Rowena, 1.9 miles east on Farm Road 2406 to intersection of county road, 4 miles south and 0.5 miles east on county road, 120 feet south in cropland (atlas sheet #68)
RANGE IN CHARACTERISTICS: Solum thickness ranges from 40 to greater than 60 inches. Distinct calcium carbonate accumulations begin at depths of 24 to 40 inches. The linear extensibility percentage exceeds 7.0; when dry, cracks 1 to 3 cm wide extend from the surface to a depth of 20 to 30 inches. Mean annual soil temperature ranges from 65 to 70 degrees F.
The A and Bw horizons have hue from 7.5YR or 10YR, value of 3 to 5, and chroma of 2 or 3. Texture is clay loam, silty clay, or clay. The clay content of the B horizons ranges from 35 to 50 percent which is slightly higher than that of the A horizons. Some pedons do not have Bw horizons.
The Bk horizon has hue of 5YR to 10YR, value of 5 or 8, and chroma of 2 to 4. Structure in the lower part is moderate fine angular blocky or moderate medium angular blocky, and in some pedons the upper few inches is angular blocky parting to moderate or weak subangular blocky. This horizon contains enough calcium carbonate to be a calcic horizon.
The BCk horizon has hue of 5YR or 7.5YR, value of 5 to 7 and chroma of 3 to 8. Texture is silty clay loam, clay loam, or clay. Calcium carbonate equivalent of the BCk horizon is 20 to 60 percent. Carbonates are in powdery masses and concretions.
COMPETING SERIES: These are the Chatt (TX) and Knippa (TX) series. Similar soils are the Abilene, Angelo, Hollister, Nuvalde, and Sagerton series. Chatt soils are moist in the soil moisture control section for longer periods of time. Knippa soils have mean annual soil temperatures more than 70 degrees F. Abilene, and Sagerton soils have Bt horizons. Hollister soils have slickensides and more than 30 percent clay in the surface layer. Angelo soils have less than 35 percent silicate clay and are in the fine-silty textural family. Nuvalde soils do not have cracks as wide as 1 cm at a depth of 20 inches from the soil surface.
GEOGRAPHIC SETTING: These soils are on nearly level plains or in broad valleys. The soil formed in calcareous clay loam to clay sediments. Slope gradients are mostly less than 1 percent but range up to 3 percent. Mean annual precipitation ranges from 20 to 28 inches, and the mean annual air temperature is from 63 degrees to 68 degrees F. Frost free days range from 210 to 240 days and elevation ranges from 1,200 to 2,250 feet. Thornthwaite P-E ranges from 25 to 44.
GEOGRAPHICALLY ASSOCIATED SOILS: These include the similar Abilene, and Sagerton series and the Lipan and Roscoe series. Lipan and Roscoe soils are in depressed areas within the landscape and have slickensides that intersect.
DRAINAGE AND PERMEABILITY: Well drained. Permeability is moderately slow. Runoff is negligible on slopes less than 1 percent and very low on 1 to 3 percent slopes.
USE AND VEGETATION: Almost all of the acreage is used as dry cropland for growing cotton, grain sorghum, and wheat. Some areas are irrigated. In the few areas of native vegetation the grasses are dominantly buffalograss, curley mesquite, and bluegrama and a few mid grasses with sparse overstory of mesquite trees.
DISTRIBUTION AND EXTENT: Rolling Limestone Prairie, Eastern Rolling Plains, and North Central Prairie of Texas. The series is extensive.
MLRA OFFICE RESPONSIBLE: Temple, Texas
SERIES ESTABLISHED: Runnels County, Texas; 1970.
REMARKS: Diagnostic horizons and features recognized in this pedon are:
Mollic epipedon - 0 to 18 inches. (Ap, A and Bw1 horizons)
Cambic horizon - 9 to 34 inches. (Bw horizon)
Calcic horizon - 34 to 60 inches. (Bk horizon)
Vertic properties - have sufficient linear extensibility for the Vertic subgroup.