LOCATION TRINITY                 TX+AL AR OK

Established Series
Rev. GLL-RM-RMR-HLH
10/2020

TRINITY SERIES

The Trinity series consists of very deep, moderately well drained, very slowly permeable soils that formed in calcareous clayey alluvium derived from mudstone. These nearly level soils occur on flood plains on river valleys and large streams on dissected plains. Slopes are typically less than 1 percent but the range is 0 to 3 percent. Mean annual precipitation is about 1193.8 mm (47 in) and the mean annual air temperature is about 17.2 degrees C (63 degrees F).

TAXONOMIC CLASS: Very-fine, smectitic, thermic Typic Hapluderts

TYPICAL PEDON: Trinity clay, occasionally flooded in pastureland at an elevation of 110 m (360.9 ft). (Colors are for moist soil unless otherwise stated.)

Ap--0 to 15 cm (0 to 6 in); 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, very sticky, very plastic; many fine roots; common fine pores; strongly effervescent; moderately alkaline; clear smooth boundary. (Thickness is 0 to 20 cm [0 to 8 in])

A--15 to 41 cm (6 to 16 in); 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, very sticky, very plastic; common fine roots; common fine pores; common prominent pressure faces; few very fine concretions of calcium carbonate; strongly effervescent, moderately alkaline; gradual wavy boundary. (Combined thickness of A horizons is 10 to 81 cm [4 to 32 in])

Bkss1--41 to 91 cm (16 to 36 in); very dark gray (5Y 3/1) clay, dark gray (5Y 4/1) dry; weak fine and very fine subangular blocky structure; very hard, firm, very sticky, very plastic; few fine roots; few fine pores; common 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.

Bkss2--91 to 163 cm (36 to 64 in); very dark gray (5Y 3/1) clay, dark gray (5Y 4/1) dry; weak coarse angular blocky structure; very hard, very firm; very sticky, very plastic; few fine roots and pores; common 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 fine strongly cemented iron-manganese concretions; strongly effervescent; moderately alkaline; diffuse wavy boundary.

Bkss3--163 to 191 cm (64 to 75 in); dark olive gray (5Y 3/2) clay, olive gray (5Y 4/2) dry; weak coarse angular blocky structure; very hard, very firm; very sticky, very plastic; few fine pores; common fine and medium distinct olive yellow (2.5Y 6/6) or(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 strongly cemented iron-manganese concretions; strongly effervescent, moderately alkaline. (Combined thickness of the Bss horizons is 122 to 203+ cm [48 to 80+ in])

TYPE LOCATION: Kaufman County, Texas; From intersection of old U.S. Hwy. 80 and Farm Road 740 in Forney, Texas approximately 6.1 miles south on Farm Road 740, 0.45 mile south on oil top road which is an extension of Farm Road 740, and 54 ft east of fence in pastureland.

USGS topographic quadrangle: Seagoville, TX;
Latitude: 32 degrees, 40 minutes, 58.83 seconds N;
Longitude: 96 degrees 30 minutes, 56.89 seconds W

Decimal Degrees
Latitude: 32.683008
Longitude: -96.515803
Datum: WGS84

RANGE IN CHARACTERISTICS:

Soil Moisture: Typic Udic soil moisture regime. The soil moisture control section is not dry in any part for as long as 90 days in normal years.
Soil Depth: very deep, greater than 203 cm (greater than 80 in)
Thickness of ochric epipedon: 10 to 81 cm (4 to 32 in)
Depth to secondary calcium carbonate: 0 to 183 cm (0 to 72 in)
Depth to cambic horizon: 10 to 81 cm (4 to 32 in)
Depth to redox concentrations: 25 to 203 cm (10 to 80 in)
Vertic features: 0 to 50 percent pressure faces starting at a depth of 0 to 81 cm (4 to 32 in); 5 to 50 percent slickensides starting at a depth of 10 to 81 cm (4 to 32 in); cracks at least 1 cm (0.4 in) wide extend from the surface to a depth of more than 20 inches when the soil is dry. Cracks are open for 60 to 90 cumulative days during most years.
Other features: Gilgai microrelief is present in undisturbed areas but is subdued with the micro highs 5 to 15 cm (2 to 6 in) higher than the micro lows. In addition, when dry, cracks 1/4 to more than 3 cm (1 in) wide extend to a depth of 51 cm (20 in) or more for less than 90 cumulative days.

Particle-size control section (weighted average)
Clay content: 60 to 80 percent
Rock fragments: 0 to 2 percent

Ap or A Horizon(s)
Hue: 10YR, 2.5Y, or 5Y
Value: 2 to 4, dry; 2 to 3, moist (some pedons have a value of 4 when moist)
Chroma: 1 to 3, dry or moist
Texture: Silty Clay, Clay
Clay Content: 45 to 80 percent
Rock fragments: amount-0 to 4 percent; size-fine to medium gravel; kind-quartzite, chert, and/or limestone
Calcium carbonate equivalent: 0 to 25 percent
Identifiable secondary carbonates: 0 to 1 percent carbonate masses or concretions, size-very-fine to fine, location-throughout
EC (dS/m): 1.6 to 4.3
Effervescence: very slight to violent
Reaction (pH): neutral to moderately alkaline (6.6 to 8.4)

Bss or Bkss Horizon(s)
Hue: 10YR, 2.5Y, or 5Y
Value: 2 to 5, dry or moist (some pedons may have a value of 6, dry or moist)
Chroma: 1 to 3, dry or moist (some pedons may have a chroma of 4 to 6, dry or moist)
Mottles: 0 to 40 percent, black, very dark gray, dark gray, gray, dark olive gray, very dark grayish brown, dark grayish brown, grayish brown, brown, olive brown, light olive brown, olive, pale olive, olive yellow (dry or moist)
Texture: Silty Clay, Clay
Clay Content: 55 to 80 percent
Redox concentrations: 0 to 20 percent masses of oxidized iron, size- fine to coarse, contrast-distinct to prominent, boundary-sharp to clear, location-in the matrix
Iron-manganese concentrations: 0 to 3 percent manganese masses, size- fine to medium; 0 to 2 percent iron-manganese concretions, size- fine to medium
Rock fragments: amount-0 to 4 percent; size-fine to medium gravel; kind-quartzite, chert, and/or limestone
Calcium carbonate equivalent: 0 to 25 percent
Identifiable secondary carbonates: 0 to 4 percent carbonate masses, concretions, or threads, size- very-fine to medium, location-throughout
EC (dS/m): 1.6 to 7.4
Effervescence: very slight to violent
Reaction (pH): neutral to moderately alkaline (6.6 to 8.4)

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.

Billyhaw soils: have a solum less than 152 cm (60 in) 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 152 cm (60 in) thick and colors with hue redder than 10YR.

GEOGRAPHIC SETTING:

Parent material: calcareous clayey alluvium derived from mudstone
Landscape: river valleys and dissected plains
Landform: flood plains
Microrelief: on subdued gilgai in undisturbed areas with microknolls 5 to 15 cm (2 to 6 in) higher than microdepressionsSlope: 0 to 3 percent, mainly less than 1 percent
Mean annual precipitation: 864 to 1321 mm (34 to 52 in)
Thornthwaite P-E Index: 52 to about 70
Mean annual air temperature: 16 to 21.1 degrees C (60 to 70 degrees F). The climate is warm and humid to sub humid.
Frost-free period: 218 to 280 days
Elevation: 30.5 to 252.7 m (100 to 829 ft)

GEOGRAPHICALLY ASSOCIATED SOILS: These are the Bunyan, Frio, Gladewater, Kaufman, Ovan, Seagoville, Tinn, and Zilaboy series.

Bunyan soils: are fluventic, have fine-loamy particle-size control sections, and are on natural levees of the floodplain
Frio soils: are cumulic, have fine particle-size control sections, and are on similar positions or closer to the main channel
Gladewater and Zilaboy soils: are on slightly lower and wetter positions. In addition, Gladewater soils have aquic soil conditions within a depth of 51 cm (20 in) and are acidic throughout.
Kaufman, Seagoville, Tinn, and Ovan soils: are on similar flood plain positions.
Seagoville, Tinn, and Ovan soils: have less than 60 percent clay in the particle-size control section
Ovan soils: have colors with chroma of 2 or 3 in the A horizon, and have cracks that stay open longer than 90 cumulative days.
Seagoville soils: are entic and have contact with underlying loamy terrace deposits within 100 cm

DRAINAGE AND PERMEABILITY:

Drainage class: moderately well
Permeability class: very slow
Runoff: high on 0 to 1 percent slopes and very high on slopes greater than 1 percent
Flooding: Occasionally to frequently flooded for brief to long durations per year

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:
General area: North Central, Central, and South Central Texas
Land Resource Region: J - Southwestern Prairies Cotton and Forage Region
Major Land Resource Area: 86A - Texas Blackland Prairie, Northern Part
Extent: extensive

SOIL SURVEY REGIONAL OFFICE (SSRO) RESPONSIBLE: Temple, Texas

SERIES ESTABLISHED: Monroe County, Mississippi; 1908.

REMARKS:

Diagnostic horizons and features recognized in this pedon are:

Particle size control section: 25 to 100 cm (10 to 40 in). (A, Bkss1, and Bkss2 horizons)Ochric epipedon: 0 to 41 cm (0 to 16 in). (Ap and A horizons)

Cambic horizon: 41 to 191 cm (16 to 75 in). (Bkss1, Bkss2, and Bkss3 horizons)

Redoximorphic concentrations: 91 to 191 cm (36 to 75 in). (Bkss2 and Bkss3 horizons)

Vertic features: The presence of slickensides at 41 to 191 cm (16 to 75 in) and cracks that remain open less than 90 cumulative days. (Bkss1, Bkss2, and Bkss3 horizons)

Identifiable secondary calcium carbonate: 41 to 191 cm (16 to 75 in). (Bkss1, Bkss2, and Bkss3 horizons)

ADDITIONAL DATA: National Soil Survey Laboratory: S77TX-175-(78P068).

Soil Interpretation Record - Trinity (TX0101), commonly flooded (TX1189), frequently flooded (TX1124), depressional (TX0919).

Taxonomic Version: Keys to Soil Taxonomy, Twelfth Edition, 2014.

---

National Cooperative Soil Survey
U.S.A.