LOCATION BERGSTROM TX+OKEstablished Series
TAXONOMIC CLASS: Fine-silty, mixed, superactive, thermic Cumulic Haplustolls
TYPICAL PEDON: Bergstrom silty clay loam - cultivated. (Colors are for dry soil unless otherwise stated.)
Ap--0 to 6 inches; dark grayish brown (10YR 4/2) silty clay loam, very dark grayish brown (10YR 3/2) moist; moderate fine granular structure; hard, very friable; few roots; few earthworm casts; strongly effervescent; moderately alkaline; abrupt smooth boundary. (4 to 8 inches thick)
A1--6 to 9 inches; dark grayish brown (10YR 4/2) silty clay loam, very dark grayish brown (10YR 3/2) moist; moderate fine granular structure; hard, friable; few roots; few fine pores; few earthworm casts; strongly effervescent; moderately alkaline; gradual smooth boundary. (3 to 18 inches thick)
A2--9 to 26 inches; dark grayish brown (10YR 4/2) silty clay loam, very dark grayish brown (10YR 3/2) moist; moderate fine subangular blocky and granular structure; hard, friable; few fine pores; strongly effervescent; moderately alkaline; clear smooth boundary. (5 to 22 inches thick)
Bw--26 to 60 inches; reddish brown (5YR 5/4) silty clay loam, reddish brown (5YR 4/4) moist; weak fine subangular blocky and granular structure; hard, friable; few fine pores; few films and threads of calcium carbonate throughout; few powdery lime masses in lower part; violently effervescent; moderately alkaline; clear smooth boundary. (16 to 32 inches thick)
C--60 to 80 inches; reddish yellow (5YR 6/6) silty clay loam, yellowish red (5YR 5/6) moist; structureless; hard, friable; contains a few thin strata and lenses that are more clayey or more sandy; a few strongly cemented calcium carbonates concretions; calcareous; moderately alkaline.
TYPE LOCATION: Travis County, Texas; 7.5 miles south, 74 degrees east of the State Capitol in Austin; 100 feet east of Farm Market 973 in a cultivated field from a point 1/2 mile south of intersection of Farm Market 973 and Farm Market 969.
RANGE IN CHARACTERISTICS: Thickness of the solum ranges from 50 to about 80 inches. The mollic epipedon ranges from 20 to 48 inches.
The A horizon has hue of 7.5YR or 10YR, value of 3 to 5 and chroma of 2 or 3. Texture is silt loam, or silty clay loam.
The Bw, and Bk horizon where present, have hue of 5YR, 7.5YR or 10YR, value of 3 to 5 and chroma of 2 to 6. Texture is silt loam, silty clay loam, or clay loam. The 10- to 40-inch control section has from 22 to 35 percent clay and more than 40 percent silt.
The C horizon is brownish, yellowish, or reddish silt loam or silty clay loam with strata of more clayey or sandy sediments.
COMPETING SERIES: These are the Biggetty (NM), Elandco (TX), Iraan (TX) and Port (OK) series. Similar soils are the Bippus, Bosque, Gageby, Gowen and Whitesboro series. Biggetty and Iraan soils are dry in the moisture control section for longer periods. Elandco and Port soils are noncalcareous to depths of more than 20 inches. Bippus, Bosque, Gageby, Gowen and Whitesboro are in the fine-loamy family. In addition, Whitesboro soils are moderately well drained.
GEOGRAPHIC SETTING: Bergstrom soils are on flood plains and low terraces along major streams. Surfaces are flat to convex. Slope gradients are mainly less than 1.0 percent but range up to 3 percent. The soil formed in calcareous silty alluvium. Mean annual rainfall ranges from 32 to 40 inches, and mean annual temperature ranges from 67 to 70 degrees F. Frost free days range form 260 to 290 days, and elevation ranges from 200 to 750 feet. Thornthwaite P-E indices range from 44 to 60.
GEOGRAPHICALLY ASSOCIATED SOILS: These include the Asa, Miller, Weswood and Yahola series. Asa soils have mollic epipedons less than 20 inches thick. Miller soils have a fine textured control section. Weswood and Yahola soils lack mollic epipedons.
DRAINAGE AND PERMEABILITY: Well drained. Permeability is moderate. Runoff is negligible on slopes less than 1 percent, and very low on 1 to 3 percent slopes.
USE AND VEGETATION: Used mainly for cultivated crops such as cotton, grain sorghums, and corn. A few small areas are used for improved pasture. Native vegetation consisted of elm, pecan, hackberry, and tall bunch grasses.
DISTRIBUTION AND EXTENT: Northern and Southern Blackland Prairies of Texas and in Oklahoma along rivers draining redbeds. Series is of moderate extent.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Temple, Texas
SERIES ESTABLISHED: Travis County, Texas; 1969.
REMARKS: Diagnostic horizons and features recognized in this pedon are:
Mollic epipedon - 0 to 26 inches. (Ap, A1 and A2 horizons)
Cambic horizon - 26 to 60 inches. (Bw horizon)