LOCATION COCHINA                 TX

Established Series
Rev. DA-WJG-CNL-CKH
11/2016

COCHINA SERIES

The Cochina series consists of very deep, moderately well drained, very slowly permeable soils formed in calcareous clayey alluvium. These nearly level soils occur on flood plains. Slope ranges from 0 to 1 percent. Mean annual precipitation is about 56 cm (22 in) and the mean annual air temperature is about 22 degrees C (72 degrees F).

TAXONOMIC CLASS: Very-fine, smectitic, hyperthermic Sodic Haplusterts

TYPICAL PEDON: Cochina clay, in rangeland; at elevation of 169.7 meters (557 feet).
(Colors are for dry soil unless otherwise stated.)

A--0 to 18 cm (0 to 7 inches); grayish brown (10YR 5/2) clay, dark grayish brown (10YR 4/2) moist; weak fine and medium subangular blocky structure; very hard, very firm, very sticky and very plastic; common fine roots; few shell fragments; EC 1.6 dS/m; slightly effervescent; moderately alkaline; gradual wavy boundary. Thickness is 10 to 30 cm (4 to 12 in)

Bw--18 to 86 cm (7 to 34 inches); grayish brown (10YR 5/2) clay, dark grayish brown (10YR 4/2) moist; moderate medium subangular blocky structure parting to moderate fine angular blocky; extremely hard, very firm, very sticky and very plastic; common fine roots; few shell fragments; few slickensides in lower part; very few brown-black concretions 1 millimeter across; EC 1.0 dS/m; strongly effervescent; moderately alkaline; diffuse wavy boundary. Thickness is 30 to 76 cm (12 to 30 in)

Bnssz--86 to 132 (34 to 52 inches); light brownish gray (10YR 6/2) clay, grayish brown (10YR 5/2) moist; moderate medium subangular blocky structure parting to moderate fine angular blocky; extremely hard, very firm, very sticky and very plastic; few fine roots; common slightly darker streaks; few slickensides; few brown-black concretions 1 millimeter across; EC 4.2 dS/m; strongly effervescent; moderately alkaline; diffuse wavy boundary. Thickness is 30 to 61 cm (12 to 24 in)

Bnssyz--132 to 183 (52 to 72 inches); pale brown (10YR 6/3) clay, brown (10YR 5/3) moist; weak fine and medium subangular blocky structure; extremely hard, very firm, very sticky and very plastic; few slickensides; few salt threads; few gypsum crystals; few brown-black concretions 1 millimeter across; EC 7.0 dS/m; strongly effervescent; moderately alkaline.

TYPE LOCATION: Zavala County, Texas; 0.5 mile south on U.S. Highway 83 from its junction with Loop 155 on southwest side of Crystal City, 150 feet west in rangeland from right-of-way fence.
USGS topographic quadrangle: Crystal City SW, Texas;
Latitude: 28 degrees, 40 minutes, 11.10 seconds N;
Longitude: 99 degrees, 50 minutes, 26.10 seconds W.;
Datum: NAD 83.

RANGE IN CHARACTERISTICS:
Soil Moisture: An aridic ustic moisture regime. The soil moisture control section is moist in some or all parts for less than 90 consecutive days in normal years.
Mean annual soil temperature: 22.2 to 24.4 degrees C (72 to 76 degrees F)
Solum thickness: 152 to 203 cm (60 to 80 in
Depth to sodic features: 41 to 102 cm (16 to 40 in)
Vertic Features: Cracks that are 1 cm (0.4 in) to 8 cm (3 in) wide and extend to a depth of 0 to 50 cm (20 in) or more.

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

A horizon
Hue: 10YR, 2.5Y
Value: 5 to 6
Chroma: 2 to 4
Texture: clay loam or clay
Clay content: 40 to 80 percent
Rock fragments: 0 to 5 percent by volume; mostly fine and medium chert gravel
Calcium carbonate equivalent: 2 to 20 percent
Electrical conductivity (mmhos/cm): 0 to 4
Sodium Adsorption Ratio: 2 to 15
Effervescence: slight or strong
Reaction (pH): slightly alkaline to moderately alkaline (7.4-8.4)

Bw or Bss horizon
Hue: 10YR, 2.5Y
Value: 5 to 6
Chroma: 2 to 4
Texture: clay
Clay content: 60 to 80 percent
Rock fragments: 0 to 5 percent by volume; mostly fine and medium chert gravel
Calcium carbonate equivalent: 2 to 25 percent
Electrical conductivity (mmhos/cm): 0 to 4
Sodium Adsorption Ratio: 2 to 15
Effervescence: slight or strong
Reaction (pH): slightly alkaline to moderately alkaline (7.4-8.4)

Bnssz horizon
Hue: 10YR, 2.5Y
Value: 5 to 7
Chroma: 2 to 4.
Texture: clay
Clay content: 55 to 80 percent
Rock fragments: 0 to 5 percent by volume; mostly fine and medium chert gravel
Calcium carbonate equivalent: 2 to 25 percent
Gypsum: 0 to 1 percent
Electrical conductivity (mmhos/cm): 4 to 16
Sodium Adsorption Ratio: 13 to 30
Effervescence: slight or strong
Reaction (pH): slightly alkaline to moderately alkaline (7.4-8.4)

Bnssyz horizon
Hue: 10YR, 2.5Y
Value: 5 to 7
Chroma: 2 to 4.
Texture: clay
Clay content: 55 to 80 percent
Rock fragments: 0 to 5 percent by volume; mostly fine and medium chert gravel
Calcium carbonate equivalent: 2 to 25 percent
Gypsum: 0 to 5 percent
Electrical conductivity (mmhos/cm): 4 to 16
Sodium Adsorption Ratio: 13 to 55
Effervescence: slight to violent
Reaction (pH): slightly alkaline to moderately alkaline (7.4-8.4)

Most pedons contain few to common vertical streaks similar to the A horizon in color and texture. Texture is clay.

COMPETING SERIES: These are the Benito and Harlingen series. Similar soils are the Arroyada, Coquat, Lomalta, Mercedes, and Monwebb soils.
Arroyada soils: have chromas of less than 1.5 in at least the upper 30 cm (12 in); have 35 to 60 percent clay in the particle-size control section.
Benito soils: have chromas of less than 1.5 in at least the upper 30 cm (12 in); are poorly drained.
Coquat soils: have 35 to 60 percent clay in the particle-size control section; cracks that remain open more than 90 days.
Harlingen soils: occur on stream terraces of the lower Rio Grande river that do not flood or are only rarely flooded
Lomalta soils: have chroma less than 1.5 in at least the upper 30 cm (12 in) and are poorly drained.
Mercedes and Monwebb soils: have chroma less than 1.5 in at least the upper 30 cm (12 in); have 35 to 60 percent clay in the particle-size control section.

GEOGRAPHIC SETTING:
Parent material: calcareous clayey alluvium
Landform: flood plains
Slope: 0 to 1 percent
Precipitation pattern: June to August and December to February are the driest months, while September to November and March to May are the wettest months.
Mean annual precipitation: 508 to 635 mm (20 to 25 in)
Thornthwaite annual P-E indices: 25 to 40
Mean annual air temperature: 21.1 to 22.2 degrees C (70 to 72 degrees F)
Frost-free period: 265 to 280 days
Elevation: 42.7 to 228.6 m (140 to 750 ft)

GEOGRAPHICALLY ASSOCIATED SOILS: These are the Brundage, Catarina, Chacon, Cotulla, Maverick, Montell, Pryor, Uvalde, and Winterhaven series.
Brundage soils: occur on a slightly higher landform; a fine-loamy particle-size control section; more saline throughout; and have a natric horizon.
Catarina and Cotulla soils: occur on a slightly higher landform; formed over claystone; have 35 to 60 percent clay in the particle-size control section.
Chacon soils: occur on a higher landscape position; have an argillic horizon; are well drained.
Maverick and Pryor soils: occur on a higher landscape position; are moderately deep over claystone or mudstone.
Uvalde soils: occur on a slightly higher landscape position; a fine-silty particle-size control section; have a mollic epipedon.
Winterhaven soils: occur on a similar landform; fine-silty particle-size control section; well drained.

DRAINAGE AND PERMEABILITY: Moderately well drained. Permeability is very slow. Runoff is slow. Flooding is occasional to frequent and has very brief to long durations.

USE AND VEGETATION: Used as rangeland. Native vegetation is dominated by large mesquite; oak and elm may make up a large percent of the overstory along stream banks. Bristlegrass, Virginia wildrye, and fourflower trichloris dominate the potential herbaceous community. Mesquite, sedges, and spiny aster are persistent increasers. Retama and sneezeweed are persistent invaders.

DISTRIBUTION AND EXTENT: Western Rio Grande Plain, Texas; LRR I, MLRA 83B; large extent.

MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Temple, Texas

SERIES ESTABLISHED: Zavala County, Texas; 1982.

REMARKS: These soils were formerly included as a phase of the Mercedes series.

Edited 11/2016 (RFG-GWH): Added clay content, CCE, EC, and SAR to the range in characteristics. Updated competing series, geographic setting, and associated soils sections.

Diagnostic horizons and features recognized in this pedon are:
Ochric epipedon - 0 to 18 cm (0 to 7 in). (A horizon)
Vertic feature: Slickensides occur from 18 to 183 cm (7 to 72 in). (BA, Bssnz, Bssnyz horizons)
Sodic feature: 86 to 183 cm (34 to 72 in) (Bz and Byz horizons)

ADDITIONAL DATA: KSSL data is available for pedon ID S11TX3111012 from McMullen Co, TX. Particle-size analysis, salinity and sodicity tests were performed at the project office on pedons S08TX3119004, P09TX3119103, S10TX3113582, S10TX3113594, and S10TX3114694.

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

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National Cooperative Soil Survey
U.S.A.