LOCATION SEJITA             TX
Established Series
Rev. ACT
02/2003

SEJITA SERIES


The Sejita series consists of very deep, poorly drained, moderately slowly permeable, saline soils that formed in marine sediments. These soils are on nearly level low coastal terraces. Slopes are less than 1 percent.

TAXONOMIC CLASS: Fine-silty, mixed, active, hyperthermic Typic Aquisalids

TYPICAL PEDON: Sejita silt loam--rangeland. (Colors are for dry soil unless otherwise stated.)

Anz--0 to 2 inches; light brownish gray (10YR 6/2) silt loam, dark grayish brown (10YR 4/2) moist weak fine subangular blocky structure; slightly hard, friable, sticky and plastic; common salt threads; strongly saline; strongly saline; strongly alkaline; clear wavy boundary. (1 to 5 inches thick)

Bnyz--2 to 7 inches; light gray (10YR 7/2) silty clay loam with common medium distinct gray (10YR 6/1) streaks, light brownish gray (10YR 6/2) moist; weak coarse angular blocky structure; hard, friable, sticky and plastic; few gypsum crystals; few fine iron-manganese concretions; common salt threads; strongly saline; strongly effervescent; strongly alkaline; gradual wavy boundary. (3 to 10 inches thick)

Bnyz--7 to 20 inches; light gray (10YR 7/2) silty clay loam, light brownish gray (10YR 6/2) moist; few gray (10YR 6/1) streaks; weak coarse prismatic structure; hard, friable, sticky, and plastic; few gypsum crystals; common masses and threads of salt; stronglysaline; strongly effervescent; strongly alkaline; diffuse wavy boundary. (10 to 17 inches thick)

Cnyz--20 to 60 inches; very pale brown (10YR 7/3) stratified silt loam, silty clay loam and clay loam, pale brown (10YR 6/3) moist; massive; hard, friable, sticky and plastic; common medium distinct dark gray (10YR 4/1) and strong brown (7.5YR 5/6) masses of iron accumulation; few gypsum crystals; few black concretions; strongly saline; strongly effervescent; strongly alkaline.

TYPE LOCATION: Cameron County, Texas; 10 miles northeast of Brownsville in a pasture 100 feet east of trail, which point is 0.6 mile north of the junction of trail and Farm Road 1792. This junction is 4.3 miles northeast of intersection of Farm Road 1792 and Farm Road 511 at Port Brownsville.

RANGE IN CHARACTERISTICS: Solum thickness ranges from 15 to 30 inches. Soil reaction ranges from slightly alkaline to strongly alkaline. Sodium saturation ratiois more than 15 percent in all horizons. Clay content of the 10- to 40-inch particle size control section ranges from 25 to 35 percent.

The A horizon has hue of 10YR, value of 5 to 7, and chroma of 2. Texture is silt loam, loam, or silty clay loam. Soil salinity ranges from 35 to 70 dS/m.

The B horizon has hue of 7.5YR or 10YR, value of 5 to 7, and chroma of 2 or 3. Texture is silt loam, silty clay loam, or clay loam. Soil salinity ranges from 16 to 32 dS/m. Structure is weak angular blocky or weak prismatic.

The C horizon has hue of 10YR, value of 6 or 7, and chroma of 2 or 3. Redoximorphic features range from few to common in shades of gray and brown. This horizon consists of stratified loam, silt loam, silty clay loam, and clay loam. Soil salinity ranges from 16 to 32 dS/m.

COMPETING SERIES: This is the only series in the family. Similar soils are the Arrada, Barrada, Latina, Saragosa, Satatton, Saucel, and Willamar series. Arrada and Latina soils are in the fine-loamy family. Barrada soils are in the fine family. Saragosa soils have a gypsic horizon, gypsic mineralogy, and occur in saline basins of west Texas. Satatton soils are in the sandy family. Saucel soils are in the coarse-loamy family. Willamar soils have a natric horizon.

GEOGRAPHIC SETTING: Sejita soils occur on nearly level areas along the lower Gulf Coast. Maximum elevation is about 7 feet. They are subject to inundation during storm periods. They have formed in stratified alluvial and marine sediments and have been modified by deposits of eolian silt and clay blown from nearby tidal flats. Mean annual precipitation ranges from 28 to 32 inches, and mean annual temperature ranges from 72 to 74 degrees F. Frost free days range from 320 to 365 days, and elevation ranges from 2 to 7 feet. Thornthwaite P-E index is 32 to 40.

GEOGRAPHICALLY ASSOCIATED SOILS: These include the Barrada, Lomalta, Point Isabel, and Willamar series. Barrada soils are at lower elevations near sea level. Lomalta and Willamar soils are at higher elevations further inland. Point Isabel soils are better drained, do not have mottled subsoils, and occupy "clayey" dune positions.

DRAINAGE AND PERMEABILITY: Poorly drained. Permeability is moderately slow. Runoff is negligible. The water table fluctuates between the surface and 24 inches most of the year.

USE AND VEGETATION: Used for range. Vegetation consists mostly of a thin stand of halophytes, chiefly bushy sea-oxeye, seashore saltgrass, screwbean, and pickleweed.

DISTRIBUTION AND EXTENT: Coastal lowlands of the Rio Grande Plain, southern Texas. Probably in Mexico. The series is of moderate extent.

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

SERIES ESTABLISHED: Cameron County, Texas; 1970.

REMARKS: Classification change from Typic Salorthids to Typic Aquisalids based on application of the 6th edition of SOIL TAXONOMY.

Diagnostic horizons and features recognized in this pedon are:

Ochric epipedon - 0 to 2 inches. (Anz horizon)

Salic horizon - 0 to 20 inches. (Anz and Bnyz horizons)

Aquic feature - Saturated with water within 40 inches of the surface for one month or more in 6 out of 10 years.

Soil Interpretation Record: TX0546


National Cooperative Soil Survey
U.S.A.