LOCATION POKORNY                 TX

Established Series
LEL, RD, ALS
07/2012

POKORNY SERIES

The Pokorny series consists of very shallow and shallow, well drained soils formed in alluvium derived from rock gypsum derived from the Castile and Salado Formations, with alluvial and eolian inputs of silicate minerals. Pokorny soils are on terraces, alluvial flats, and low hills of Pleistocene age. Slopes range from 0 to 8 percent. Mean annual air temperature is about 65 degrees F. (18 degrees C) and the mean annual precipitation is about 13 inches (330 mm).

TAXONOMIC CLASS: Fine-gypseous, hypergypsic, thermic, shallow Ustic Petrogypsids

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

A--0 to 1 inches; (0 to 3 cm); yellowish brown (10YR 5/4) loam, brown (10YR 4/3) moist; 12 percent clay; weak thin platy structure; slightly hard, very friable, slightly sticky and slightly plastic; common very fine and fine roots; common very fine and fine pores; 2 percent very coarse prominent irregular insect casts; 1 percent medium distinct platy moderately cemented carbonate nodules; 18 percent calcium carbonate equivalent; strongly effervescent; slightly alkaline (pH 7.8); clear smooth boundary. (0 to 4 inches [0 to 10 cm] thick)

Byy1--1 to 6 inches, (3 to 15 cm); white (10YR 8/1) gypsiferous silt loam, white (10YR 8/1) moist; moderate medium subangular blocky parting to moderate fine subangular blocky structure; slightly hard, friable, slightly sticky and moderately plastic; common very fine, fine and medium roots; common fine pores; 4 percent calcium carbonate equivalent; slightly effervescent; 86 percent gypsum; slightly alkaline (pH 7.8); gradual smooth boundary.

Byy2--6 to 17 inches, (15 to 43 cm); white (10YR 8/1) gypsiferous silty clay loam, pale yellow (2.5Y 8/2) moist; moderate coarse prismatic structure; slightly hard, friable, very sticky and moderately plastic; brittle; common very fine, fine and medium roots in cracks; common fine pores; 2 percent prominent carbonate coats on vertical faces of peds; 2 percent calcium carbonate equivalent; slightly effervescent; 88 percent gypsum; moderately alkaline (pH 8.0); abrupt smooth boundary. (Combined thickness of Byy horizons is 4 to 17 inches [10 to 43 cm])

Byym1--17 to 28 inches (43 to 71 cm); very pale brown (10YR 8/3) gypsiferous cemented material, light yellowish brown (10YR 6/4) moist; strong coarse prismatic structure; moderately cemented, moderately sticky and slightly plastic; brittle; common very fine and fine roots in cracks; common medium roots at top of horizon; 2 percent prominent carbonate coats on vertical prism faces; 11 percent calcium carbonate equivalent; strongly effervescent; 61 percent gypsum; moderately alkaline (pH 8.2); clear smooth boundary.

Byym2--28 to 37 inches, (71 to 94 cm); white (10YR 8/1) gypsiferous cemented material, pale yellow (2.5Y 8/3) moist; strong coarse prismatic structure; moderately cemented, moderately sticky and moderately plastic; brittle; few very fine and fine roots in cracks; 2 percent prominent carbonate coats on vertical prism faces; 9 percent calcium carbonate equivalent; strongly effervescent; 80 percent gypsum; moderately alkaline (pH 8.1); clear smooth boundary.

Byym3--37 to 52 inches, (94 to 132 cm); white (10YR 8/1) gypsiferous cemented material, pale yellow (2.5Y 8/3) moist; strong coarse prismatic structure; weakly cemented, slightly sticky and slightly plastic; brittle; few very fine and fine roots in cracks; 2 percent prominent carbonate coats on vertical faces of peds; 6 percent calcium carbonate equivalent; strongly effervescent; 81 percent gypsum; moderately alkaline (pH 8.2); clear smooth boundary.

Byym4--52 to 80 inches, (132 to 203 cm); white (10YR 8/1) gypsiferous cemented material, pale yellow (2.5Y 8/3) moist; strong coarse prismatic structure; weakly cemented, slightly sticky and nonplastic; brittle; few very fine and fine roots in cracks; 2 percent prominent carbonate coats on vertical faces of peds; 6 percent calcium carbonate equivalent; strongly effervescent; 86 percent gypsum; moderately alkaline (pH 8.2). (Combined thickness of Byym horizons is 10 to 70 inches [25 to 178 cm])

TYPE LOCATION: Culberson County, Texas; from the intersection of U.S. Highways 62-180 and RM 652 at the New Mexico state line; 16.2 miles south and east on RM 652 to ranch gate; 2.0 miles south on ranch road; and 110 feet west in range. (Castile Hill TX USGS 7.5 minute topographic quadrangle; Latitude: 31 degrees, 52 minutes, 7.20 seconds N, Longitude: 104 degrees, 19 minutes, 50.30 seconds W, NAD83 UTM Easting 563315 m, UTM Northing 3526073 m, UTM Zone 13, NAD83.)

RANGE IN CHARACTERISTICS:

Soil moisture: The soil is intermittently moist in some part of the soil moisture control section during July to September. It is driest during November to March. Most precipitation occurs as high intensity rain during afternoon convective thunderstorms from June to September.
Ustic aridic soil moisture regime

Soil temperature: 62 to 65 degrees F. (17 to 18 degrees C)

Depth to hypergypsic horizon: 0 to 4 inches (0 to 10 cm)

Depth to petrogypsic horizon: 4 to 20 inches (10 to 50 cm)

A horizon
Hue: 10YR, 2.5Y
Value: 5 to 8 dry, 4 to 7 moist
Chroma: 1 to 4, dry or moist
Texture: fine sandy loam, sandy loam, loam, silty clay loam
Silicate clay content: 10 to 28 percent
Calcium carbonate equivalent: 10 to 20 percent
Gypsum content: 0 to 10 percent
Effervescence class: slight to strong
Reaction: slightly alkaline to moderately alkaline

Byy horizon
Hue: 10YR, 2.5Y
Value: 7 or 8, dry or moist
Chroma: 1 to 3, dry or moist
Texture: gypsiferous fine sandy loam, gypsiferous loam, gypsiferous clay loam, gypsiferous silt loam, gypsiferous silty clay loam
Calcium carbonate equivalent: 1 to 5 percent
Gypsum content: 80 to 95 percent
Effervescence class: slight to strong
Reaction: slightly alkaline to moderately alkaline

Byym horizon
Hue: 10YR, 2.5Y
Value: 6 to 8, dry or moist
Chroma: 1 to 4, dry or moist
Cementation class: extremely weakly cemented to strongly cemented
Calcium carbonate equivalent: 5 to 15 percent
Gypsum content: 60 to 90 percent

COMPETING SERIES: This is the Hollebeke (T) (TX) series. Hollebeke soils have a lithic contact within 20 inches (50 cm)of the surface.

GEOGRAPHIC SETTING: Pokorny soils are on terraces, alluvial flats, and low hills of Pleistocene age in karst. They formed in alluvium derived from rock gypsum derived from the Castile and Salado Formations, with alluvial and eolian inputs of silicate minerals. Slope range is 0 to 8 percent. Elevation is 4,000 to 5,500 feet (1,219 to 1,676 m). The mean annual precipitation is 12 to 16 inches (305 to 406 mm). The mean annual air temperature ranges from 62 to 67 degrees F. (17 to 19 degrees C). The frost-free period is about 210 to 250 days.

GEOGRAPHICALLY ASSOCIATED SOILS: These are the Dellahunt (T) (TX), Elcor (T) (TX), Hollebeke (T) (TX), Hollomex (NM), Joberanch (T) (TX), Niemahr (T) (TX), and Walkerwells (T) (TX) series. Dellahunt and Walkerwells soils are deep and occur on lower positions. Elcor and Hollebeke soils have a lithic contact within 20 inches (50 cm) of the surface and occur higher in the landscape. Hollomex soils do not have a petrogypsic horizon and occur on similar landscapes. Joberanch soils have more than 6 inches (15 cm) of silicate material above a petrogypsic horizon and occur on similar landscapes. Niemahr soils have more than 6 inches (15 cm) of silicate material above a lithic contact and occur on lower positions.

DRAINAGE AND PERMEABILITY: Well drained; low runoff; moderate permeability.

USE AND VEGETATION: Used for livestock grazing and wildlife habitat. Vegetation physiognomy is desert grassland. Vegetation includes littleleaf sumac, creosote bush, fourwing saltbush, soaptree yucca,gyp grama, gyp dropseed, and rough coldenia.

DISTRIBUTION AND EXTENT: LRR-D, MLRA 42, Southern Desertic Basins, Plains, and Mountains, Desert Grassland LRU. Trans-Pecos Texas in areas of Permian-age Castile formation. The series is moderately extensive.

MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Phoenix, Arizona

SERIES ESTABLISHED: Hudspeth County, Texas; Soil Survey of Hudspeth County, Texas (Main Part), 2012.

REMARKS: Diagnostic horizons and features recognized in this pedon are:

Ochric epipedon - the zone from 0 to 1 inch (0 to 3 cm) A horizon

Gypsic horizon - the zone from 1 to 17 inches (3 to 43 cm) (Byy horizons)

Petrogypsic horizon - the zone from 17 to 80 inches (43 to 203 cm) (Byym horizons)

Soil classified according to Soil Taxonomy, Second Edition, 1999; Keys to Soil Taxonomy, Eleventh Edition, 2010

Revised for the correlation of Hudspeth County, Texas (Main Part) and Culberson County, Texas (Main Part); July, 2012, NMS

ADDITIONAL DATA: Characterization data from National Soil Survey Laboratory are available for the typical pedon, S06-TX109-902

---

National Cooperative Soil Survey
U.S.A.