LOCATION TRINITY TX+AL AR OKEstablished Series
TAXONOMIC CLASS: Very-fine, smectitic, thermic Typic Hapluderts
TYPICAL PEDON: Trinity clay--pasture. (Colors are for moist soil unless otherwise stated.)
Ap--0 to 6 inches; very dark gray (5Y 3/1) clay, dark gray (5Y 4/1) dry; moderate fine and medium granular and moderate fine subangular blocky structure; very hard, firm, sticky, very plastic; many fine roots; common fine pores; strongly effervescent; moderately alkaline; clear smooth boundary. (0 to 8 inches thick)
A--6 to 16 inches; very dark gray (5Y 3/1) clay, dark gray (5Y 4/1) dry; moderate medium subangular blocky structure parting to very fine subangular blocky; very hard, firm, sticky, very plastic; common fine roots; common fine pores; many prominent pressure faces; few very fine concretions of calcium carbonate; strongly effervescent, moderately alkaline; gradual wavy boundary. (8 to 24 inches thick)
Bss1--16 to 36 inches; very dark gray (5Y 3/1) clay, dark gray (5Y 4/1) dry; weak fine and very fine subangular blocky structure; very hard, firm, sticky, very plastic; few fine roots; few fine pores; many prominent pressure faces; common prominent grooved slickensides that increase with depth; few very fine and fine concretions of calcium carbonate; strongly effervescent; moderately alkaline; diffuse wavy boundary.
Bss2--36 to 64 inches; very dark gray (5Y 3/1) clay, dark gray (5Y 4/1) dry; weak coarse blocky structure; very hard, very firm; few fine roots and pores; many prominent grooved slickensides; common fine and medium distinct olive yellow (5Y 6/6) and yellowish brown (10YR 5/8) redox concentrations; common fine and medium concretions of calcium carbonate; few hard black concretions; strongly effervescent; moderately alkaline; diffuse wavy boundary.
Bss3--64 to 75 inches; dark olive gray (5Y 3/2) clay, olive gray (5Y 4/2) dry; weak coarse angular blocky structure; very hard, very firm; common fine and medium distinct olive yellow (2.5Y 6/6; 5Y 6/8) and few coarse distinct light olive brown (2.5Y 5/4) redox concentrations; few prominent slickensides; common very fine and medium concretions of calcium carbonate; common fine black concretions; strongly effervescent, moderately alkaline. (combined thickness of Bss horizons is 40 to 70 inches)
TYPE LOCATION: Kaufman County, Texas; from intersection of old U.S. Hwy. 80 and Farm Road 740 in Forney; 6.1 miles south on Farm Road 740; 0.45 mile south on oil top road which is an extension of Farm Road 740; 54 feet east of fence.
RANGE IN CHARACTERISTICS: Solum thickness is more than 80 inches. Gilgai microrelief is present in undisturbed areas but is subdued with the micro highs 2 to 6 inches higher than the micro lows. When dry, cracks 1/4 to more than 1 inch wide extend to a depth of 20 inches or more for less than 90 cumulative days. Grooved slickensides typically begin at a depth of 12 to 24 inches and increase in number and size with depth. Clay content of the control section ranges from 60 to 80 percent. The soil is slightly alkaline or moderately alkaline and slightly or strongly effervescent throughout.
The A horizon has hue of 10YR, 2.5Y, or 5Y, with values of 2 to 3 and chroma of 1.
The Bss or Bkss horizons have hue of 10YR, 2.5Y, or 5Y, value of 2 to 5, and chroma of 2 or less. Few to common masses of redox concentrations in shades of yellow, brown, or olive are in the lower part. Calcium carbonate in the form of masses, concretions, and threads range from none to common.
COMPETING SERIES: These are the Billyhaw, Kaufman, and Wiergate series in the same family and the Hallsbluff, Kaman, Pledger, Texark, Tinn, and Zilaboy series in similar families. The Billyhaw soils have a solum less than 60 inches thick and colors with hue redder than 10YR. Kaman, Kaufman, Texark, and Wiergate soils are noncalcareous in the A horizon. Hallsbluff, Kaman, Tinn, and Zilaboy soils average less than 60 percent clay in the particle-size control section. Kaman and Zilaboy soils are wet for longer periods. Pledger soils have a hyperthermic temperature regime and, in addition, Pledger soils have sola less than 60 inches thick and colors with hue redder than 10YR.
GEOGRAPHIC SETTING: Trinity soils are on nearly level, wide flood plains of major rivers and streams. Slopes are mainly less than 1 percent but range up to 3 percent. The soil formed in calcareous clayey alluvium. The climate is warm and humid to subhumid. The mean annual precipitation ranges from 34 to 52 inches and mean annual temperatures range from 62 to 70 degrees F. Frost free days range from 230 to 280 days and elevation ranges from 100 to 550 feet. Thornthwaite P-E indices range from 52 to about 70.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the competing Kaufman, Tinn, and Zilaboy series and the Gladewater and Ovan series. Ovan soils have less than 60 percent clay in the particle-size control section, have colors with chroma of 2 or 3 in the A horizon, and have cracks that stay open longer than 90 cumulative days. Gladewater soils have aquic soil conditions within a depth of 20 inches. Gladewater and Zilaboy soils are on slightly lower and wetter positions. Kaufman, Tinn, and Ovan soils are on similar flood plain positions.
DRAINAGE AND PERMEABILITY: Moderately well drained. Runoff is low on 0 to 1 percent slopes and medium on 1 to 3 percent slopes. Permeability is very slow. Flooding is common except where the soil is protected.
USE AND VEGETATION: Most areas are in pasture or planted to crops such as cotton, corn, sorghums, or small grains. Native vegetation is hardwood forest of elm, hackberry, oak, and ash.
DISTRIBUTION AND EXTENT: North Central, Central, and South Central Texas. The series is extensive.
MLRA OFFICE RESPONSIBLE: Temple, Texas
SERIES ESTABLISHED: Monroe County, Mississippi; 1908.
REMARKS: Diagnostic horizons and features recognized in this pedon are:
Mollic epipedon - the A horizon from 0 to 16 inches.
Cambic horizon - the Bss horizon from 16 to 75 inches.
Vertic properties - gilgai microrelief in undisturbed areas, slickensides at a depth of 16 to 75 inches, and cracks that remain open less than 90 cumulative days.
ADDITIONAL DATA: National Soil Survey Laboratory: S77TX-175-(78P068).
Soil Interpretation Record - Trinity (TX0101), commonly flooded (TX1189), frequently flooded (TX1124), depressional (TX0919).