LOCATION DELMITA TXEstablished Series
TAXONOMIC CLASS: Fine-loamy, mixed, active, hyperthermic Petrocalcic Paleustalfs
TYPICAL PEDON: Delmita fine sandy loam--rangeland. (Colors are for dry soil unless otherwise stated.)
A--0 to 14 inches; reddish brown (5YR 5/4) fine sandy loam; reddish brown (5YR 4/4) moist; massive; hard; friable, slightly sticky and slightly plastic; common fine roots and pores; neutral; clear smooth boundary. (9 to 20 inches thick)
Bt--14 to 30 inches; red (2.5YR 4/6) sandy clay loam; dark red (2.5YR 3/6) moist; moderate coarse prismatic structure parting to weak fine subangular blocky; very hard, friable, sticky and slightly plastic; few fine roots; few fine pores; few faint clay films on surfaces of peds and lining pores; neutral; abrupt wavy boundary. (11 to 28 inches thick)
Bkm--30 to 60 inches; very pale brown (10YR 8/2) caliche, upper part is coarse platy with etched, fine laminated, indurated upper surface layer, becoming less cemented and massive with depth.
TYPE LOCATION: Starr County, Texas; 5.5 miles east of LaGloria on Farm Road 1017; 1800 feet south on Farm Road 2294, 150 feet west in rangeland.
RANGE IN CHARACTERISTICS:
Soil Moisture: An ustic moisture regime bordering on aridic. The soil moisture control section remains moist in some or all parts for less than 90 consecutive days in normal years. The soil is driest during the months June through August and December through February. These soils are intermittently moist in September through November and march through May.
Mean annual soil temperature: 72 to 76 degrees F.
Depth to argillic horizon: 9 to 20 inches, which corresponds to the thickness of the A horizon.
Depth to petrocalcic horizon: 20 to 40 inches
Particle-size control section (weighted average)
Clay content: 18 to 30 percent
Coarse Fragments: 0 to 5 percent
CEC/clay ratio: 0.40 to 0.60
A Horizon
Hue: 2.5YR, 5YR, 7.5YR
Value: 4 to 6
Chroma: 4 to 6
Texture: loamy fine sand, fine sandy loam
Clay content: 5to 18ercent
Base saturation: 75 to 100 percent
Calcium carbonate equivalent: 0 to 2 percent
Effervescence: noneffervescent
Reaction: neutral or slightly alkaline
Bt Horizon
Hue: 2.5YR, 5YR
Value: 4 to 6
Chroma: 4 to 6
Texture: fine sandy loam, sandy clay loam
Clay content: 18 to 30 percent
Clay films: few or common, faint or distinct, on surfaces of peds and lining pores.
Redox accumulations: A few redox features that are reddish and brownish occur in the lower few inches of some pedons.
Base saturation: 100 percent
Calcium carbonate equivalent: 0 to 2 percent
Reaction: neutral or slightly alkaline
The Bkm horizon is indurated to strongly cemented with the upper boundary wavy to irregular. Cementation decreases with depth.
COMPETING SERIES: There are no competing series in the same family. Similar
soils are the
Duval,
Goliad,
Randado, and
Webb series.
Duval and
Webb soils: do not have a petrocalcic horizon. In addition, Webb soils have more than 35 percent clay in the B horizon.
Goliad soils: have more than 35 percent clay in the B horizon.
Randado soils: have sola less than 20 inches thick.
GEOGRAPHIC SETTING:
Parent material: loamy sediments over thick beds of caliche.
Landform: featureless upland plains
Slope: 0 to 3 percent
Mean annual air temperature: 70 to 74 degrees F.
Mean annual precipitation: 18 to 28 inches
Precipitation pattern: moist spring and fall and dry winter and summer months.
Frost-free period: 280 to 365 days
Elevation: 100 to 750 feet
Thornthwaite annual P-E indices: 22 to 34
GEOGRAPHICALLY ASSOCIATED SOILS: These are the Brennan, Cuevitas, Randado, and Zapata series.
Brennan soils: do not have a petrocalcic horizon, and occur on similar surfaces.
Cuevitas,
Randado, and
Zapata soils: occur at slightly higher elevations.
Cuevitas and Zapata soils: have sola less than 20 inches deep and occur at slightly higher positions in the landscape.
Randado soils: occur at slightly higher positions in the landscape.
DRAINAGE AND PERMEABILITY: Well drained. Permeability is moderate. Runoff is negligible on slopes less than 1 percent, and very low on slopes 1 to 3 percent slopes.
USE AND VEGETATION: Used predominantly as native rangeland of moderate carrying capacity. About 20 percent is dry land cultivated to cotton, grain sorghum, watermelon, and improved pastures. A few areas are irrigated and produce such crops as citrus, cotton, sorghums, and winter vegetables. Principal grasses of uncultivated areas include midgrass such as Arizona
cottontop, lovegrass tridens, plains bristlegrass and pink pappusgrass. Woody vegetation which comprises moderately dense overstory include mesquite, catclaw, lime pricklyash, desert yaupon, and pricklypear.
DISTRIBUTION AND EXTENT: Southern Texas, mostly in the southwestern parts of the Rio Grande Plain, Texas; LRR I; MLRA 83C; the series is extensive.
MLRA OFFICE RESPONSIBLE: Temple, Texas
SERIES ESTABLISHED: Jim Hogg County, Texas, 1970.
REMARKS: Diagnostic horizons and features recognized in this pedon are:
Particle size control section: 14 to 30 inches. (Bt horizon)
Ochric epipedon: 0 to 14 inches. (A horizon)
Argillic horizon: 14 to 30 inches. (Bt horizon)
Petrocalcic horizon: below 30 inches. (Bkm horizon)
The assignment of the cation-exchange activity class is inferred from lab data from surrounding counties in the region.
Taxonomic version: Second Edition, 1999