LOCATION BRAZORIA TXEstablished Series
TAXONOMIC CLASS: Very-fine, smectitic, hyperthermic Chromic Hapluderts
TYPICAL PEDON: Brazoria clay, on a nearly level 0.2 percent slope, in woodland. (Colors are for moist soil unless otherwise stated.)
A--0 to 20 inches; dark reddish brown (5YR 3/3) clay, reddish brown (5YR 4/3) dry; moderate medium subangular blocky and granular structure; very hard, firm, sticky and plastic; common fine roots; few concretions of calcium carbonate; strongly effervescent; moderately alkaline; clear wavy boundary. (5 to 24 inches thick)
Bss1--20 to 35 inches; dark reddish brown (5YR 3/2) clay, dark reddish gray (5YR 4/2) dry; moderate medium subangular blocky structure; very hard, firm, very sticky and plastic; few fine roots; few fine pores; common distinct pressure faces; common distinct slickensides; few old cracks partially filled with soil material; few small masses and few concretions of calcium carbonate; strongly effervescent; moderately alkaline; gradual wavy boundary. (12 to 30 inches thick)
Bss2--35 to 65 inches; dark reddish brown (5YR 3/4) clay, reddish brown (5YR 4/4) dry; moderate medium and fine subangular blocky structure; very hard, very firm, very sticky and plastic; few fine roots; few distinct slickensides; few cracks and few root channels partially filled with darker soil material; few concretions of calcium carbonate up to 1/2 inch in diameter; few masses of calcium carbonate; strongly effervescent; moderately alkaline.
TYPE LOCATION: Brazoria County, Texas; from the intersection of Texas Highway 288 and Farm Road 1462 in Rosharon, 7.8 miles west on Farm Road 1462, 200 feet south in wooded area.
RANGE IN CHARACTERISTICS: Solum thickness is more than 80 inches. The soil is calcareous throughout and secondary soft powdery lime ranges from none to common. Weighted average clay content of the particle-size control section ranges from 60 to 80 percent. Cracks more than 1 cm wide extend from the surface to depth of about 40 inches during some seasons in most years. Cracks remain open for less than 90 cumulative days in most years. Slickensides and wedge shaped peds range from few to common and begin at a depth ranging from 15 to 25 inches. Undisturbed areas have slight gilgai, with microhighs 2 to 6 inches higher than microlows. Distance between the microhigh and microlow ranges from 6 to 10 feet. Boundary between horizons is wavy with amplitude of 10 inches between the highs and lows. Buried horizons occur in some pedons.
The A horizon has hue of 5YR or 7.5YR, value of 2 or 3, and chroma of 3 or 4. Texture is clay or silty clay. Redoximorphic features range from none to few in shades of red. Reaction is slightly alkaline or moderately alkaline.
The Bss horizon has hue of 2.5YR to 7.5YR, value of 3 to 5, and chroma of 2 to 6. Redoximorphic features range from none to few in shades of yellow, brown, or red. Reaction is slightly alkaline or moderately alkaline. Calcium carbonate equivalent ranges from 0 to 20 percent by volume. Calcium carbonate in the form of masses, and concretions range from none to about 2 percent.
Some pedons have buried horizons at depths greater than 40 inches. These horizons are usually clay, but include clay loam, silty clay loam, or silty clay.
COMPETING SERIES: This is the Dylan series. Similar soils are Morse, Pledger and Ships series. Dylan soils have iron depletions due to current day wetness within 40 inches of the surface. Morse and Ships soils are in the thermic temperature regime. In addition, Morse soils have a fine particle-size control section. Pledger soils have chroma of 1 or 2 and value of 3 or less in the upper 12 inches.
GEOGRAPHIC SETTING: Brazoria soils are on nearly level flood plains of the Coast Prairie. Slopes are mainly less than 1 percent, but the slope ranges from 0 to 5. The soil formed in alkaline clayey alluvial sediments. Mean annual precipitation ranges from 40 to 55 inches. Mean annual temperature is about 70 to 72 degrees F. Frost free days range from 260 to 280. Elevation ranges from 10 to 150 feet. The Thornthwaite P-E indices is 60 to 66.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the competing Pledger series and the Asa, Clemville, Lake Charles, Laewest, and Norwood series. Asa and Norwood soils are on slightly higher positions and have loamy particle-size control sections. Clemville soils are slightly higher and have fine-silty particle-size control sections. Pledger soils are on similar positions. Lake Charles and Laewest soils are on slightly higher upland position. They have chroma of 1 or less and are not calcareous in the upper part.
DRAINAGE AND PERMEABILITY: Moderately well drained. Permeability is very slow. Runoff is low on slopes less than 1 percent, medium on 1 to 3 percent slopes, and high on 3 to 5 percent slopes. The overwash and depressional phases are somewhat poorly drained. The soil floods rarely or commonly, except where protected.
USE AND VEGETATION: Mainly used as cropland for production of cotton, sorghum, corn, and soybeans. Some areas are used for improved pasture of bermudagrass, dallisgrass, and white clover. Native vegetation is pecan, elm, hackberry, oak, and ash trees and mid and tall grasses.
DISTRIBUTION AND EXTENT: Mainly along the lower reaches of the Brazos and Colorado Rivers in the Coast Prairie (MLRA 150A). The series is of large extent.
MLRA OFFICE RESPONSIBLE: Temple, Texas
SERIES ESTABLISHED: Brazoria County, Texas; 1978.
REMARKS: Classification change from mixed to smectitic based laboratory data from Colorado County and Washington County. Laboratory data from Brazoria County indicates mixed mineralogy, but very close to smectitic.
Diagnostic horizons and features recognized in this pedon are:
Mollic epipedon -- A horizon from 0 to 20 inches and Bss1 horizon from 20 to 35 inches. Also includes the chromic feature with chroma of 3 or more.
Cambic horizon -- Bss2 horizon from 35 to 65 inches.
Vertic features -- Slickensides from a depth of 20 to 65 inches in the Bss horizons. Cracks when dry that remain open for 90 cumulative days or less each year.
ADDITIONAL DATA: National Soil Survey Laboratory samples S76TX-039-5 and S76TX-477-1.
Soil Interpretation Record: TX0758, TX0968 (depressional), TX1025 (overwash).