LOCATION BOOKOUT                 TX

Established Series
Rev. WJG-MLG-GWH
02/2018

BOOKOUT SERIES

The Bookout series consists of very deep, well drained, moderately permeable soils formed in calcareous loamy and clayey alluvium. These soils occur on stream terraces on inland dissected coastal plains. Slope ranges from 0 to 5 percent. Mean annual air temperature is about 21.7 degrees C (71 degrees F) and mean annual precipitation is about 533 mm (21 in).

TAXONOMIC CLASS: Fine-silty, mixed, superactive, hyperthermic Aridic Calciustepts

TYPICAL PEDON: Bookout clay loam on an east facing 1 percent slope in rangeland; elevation is 194 meters (638 feet). (Colors are for dry soil unless otherwise stated.)

A1--0 to 3 cm (0 to 1 in); pale brown (10YR 6/3) clay loam, brown (10YR 4/3) moist; weak platy and weak fine subangular blocky structure; slightly hard, very friable; common fine roots; few snail shell fragments; 18 percent calcium carbonate equivalent; strongly effervescent; moderately alkaline; abrupt smooth boundary. Thickness is 1/2 to 5 cm (1/4 to 2 in)

A2--3 to 36 cm (1 to 14 in); pale brown (10YR 6/3) clay loam, brown (10YR 4/3) moist; moderate fine and medium subangular blocky structure; hard, friable; many fine roots; many fine pores and old root channels; few wormcasts; few snail shell fragments; 19 percent calcium carbonate secondary; strongly effervescent; moderately alkaline; gradual smooth boundary. Combined thickness of the A horizons is 18 to 56 cm (7 to 22 in)

Bk1--36 to 61 cm (14 to 24 in); pale brown (10YR 6/3) clay loam, brown (10YR 4/3) moist; moderate fine and medium subangular blocky structure; hard, friable; common fine roots; few fine pores and old root channels; few wormcasts and termite tunnels; few snail shell fragments; 2 percent, fine threads, and fine and medium soft masses of calcium carbonate; 23 percent calcium carbonate equivalent; strongly effervescent; moderately alkaline; gradual wavy boundary. Thickness is 18 to 61 cm (7 to 24 in)

Bk2--61 to 89 cm (24 to 35 in); very pale brown (10YR 7/3) clay, pale brown (10YR 6/3) moist; weak fine and medium subangular blocky structure; hard, friable; few fine roots; 10 percent, fine threads, and medium and coarse soft masses of calcium carbonate; 31 percent calcium carbonate equivalent; violently effervescent; moderately alkaline; gradual wavy boundary. Thickness is 15 to 51 cm (6 to 20 in)

Bk3--89 to 127 cm (35 to 50 in); very pale brown (10YR 8/4) clay, very pale brown (10YR 7/4) moist; weak fine and medium subangular blocky structure; hard, firm; few fine roots; 10 percent, fine threads, and medium and coarse soft masses and concretions of calcium carbonate; about 46 percent calcium carbonate equivalent; violently effervescent; moderately alkaline; gradual wavy boundary. Thickness is 0 to 51 cm (0 to 20 in)

Bk4--127 to 163 cm (50 to 64 in); very pale brown (10YR 8/4) silty clay, light yellowish brown (10YR 6/4) moist; weak fine and medium subangular blocky structure; very hard, firm; 25 percent fine threads, and 2 percent medium and coarse concretions and soft masses of calcium carbonate; about 47 percent calcium carbonate equivalent; violently effervescent; moderately alkaline; diffuse wavy boundary. Thickness is 0 to 51 cm (0 to 20 in)

Bk5--163 to 203 cm (64 to 80 in); pink (7.5YR 8/4) silty clay, pink (7.5YR 7/4) moist; weak fine and medium subangular blocky structure; very hard, firm; 25 percent fine threads, and 2 percent medium and coarse concretions and soft masses of calcium carbonate; 45 percent calcium carbonate equivalent; violently effervescent; moderately alkaline.

TYPE LOCATION: Zavala County, Texas; from junction of U.S. Highway 83 and Farm Road 1433 on the north side of Crystal City, 7.0 miles north of U.S. Highway 83; 7.6 miles east of on Farm Road 1025 and 150 feet north in rangeland.
USGS topographic quadrangle: Batesville SW, Texas;
Latitude: 28 degrees, 47 minutes, 23.00 seconds N;
Longitude: 99 degrees, 43 minutes, 38.00 seconds W.;
Datum: WGS 84.

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.
Solum thickness: 150 to more than 200 cm (60 to more than 80 in)
Mean annual soil temperature: 22 to 24 degrees C (72 to 75 degrees F).
Depth to secondary calcium carbonate: 18 to 56 cm (7 to 22 in)
Depth to calcic horizon: 30 to 81 cm (12 to 32 in)

Particle size control section (weighted average)
Silicate clay content: 18 to 35 percent
Calcium carbonate equivalent: 20 to 40 percent

A Horizon
Hue: 10YR
Value: 5 to 7
Chroma: 2 or 3
Texture: clay loam or silty clay loam
Total clay content: 28 to 40 percent
Carbonate clay content: 3 to 10 percent
Calcium carbonate equivalent: 4 to 25 percent
Effervescence: slight to strong
Reaction (pH): slightly alkaline to moderately alkaline (7.4 - 8.4)

Bk1 Horizon
Hue: 7.5YR or 10YR
Value: 6 to 8
Chroma: 3 or 4
Texture: clay, clay loam, silty clay loam, silty clay
Total clay content: 28 to 50 percent
Carbonate clay content: 6 to 12 percent
Identifiable secondary carbonate: 1 to 5 percent, fine to coarse, threads, masses and concretions in matrix.
Calcium carbonate equivalent: 10 to 40 percent
Effervescence: strong or violent
Reaction (pH): slightly alkaline to moderately alkaline (7.4 - 8.4)

Lower Bk Horizons (Calcic horizon)
Hue: 7.5YR or 10YR
Value: 6 to 8
Chroma: 3 or 4
Texture: clay, clay loam, silty clay loam, silty clay
Clay content: 28 to 50 percent
Carbonate clay content: 7 to 20 percent
Identifiable secondary calcium carbonate: 1 to 25 percent, fine to coarse, threads, masses and concretions in matrix.
Calcium carbonate equivalent: 15 to 50 percent
Effervescence: strong or violent
Reaction (pH): slightly alkaline to strongly alkaline (7.4 - 9.0)

COMPETING SERIES: There are no series in the same family. Similar soils are the Aguilares, Atco, McAllen, Moglia, Sabenyo, and Uvalde series.
Aguilares soils: have a fine-loamy textured particle-size control section and formed in calcareous, loamy residuum weathered from sandstone
Atco soils: have carbonatic mineralogy and a coarse-loamy particle-size control section
McAllen soils: have a fine-loamy particle-size control section
Moglia soils: have a fine-loamy particle-size control section and formed in calcareous, saline, loamy residuum weathered from mudstone
Sabenyo soils: have carbonatic mineralogy and a fine-loamy particle-size control section
Uvalde soils: have a mollic epipedon

GEOGRAPHIC SETTING:
Parent material: calcareous loamy or clayey alluvium
Landscape: inland, dissected coastal plain
Landform: stream terraces
Slope: 0 to 5 percent but are mainly less than 1.5 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: 457 to 660 mm (18 to 26 in)
Thornthwaite annual P-E indices: 24 to 31
Mean annual air temperature: 21.1 to 22.2 degrees C (70 to 72 degrees F)
Frost free period: 270 to 300 days
Elevation: 91.4 to 274.3 m (300 to 900 ft)

GEOGRAPHICALLY ASSOCIATED SOILS: These are the Winterhaven, Caid, Conalb, Divot, Pryor, Uvalde, and Valco series.
Caid soils: occur on similar surfaces; have a mollic epipedon; have a fine-loamy textured particle-size control section
Conalb soils: occur on lower flood plains; have a coarse-silty textured particle-size control section
Divot soils: occur on lower flood plains; have a mollic epipedon and a fine textured particle-size control section
Pryor soils: occur at higher elevations; are deep to claystone
Uvalde soils: occur at slightly higher elevations; have a mollic epipedon
Valco soils: occur at slightly higher elevations; have mollic epipedons and are shallow over a petrocalcic horizon
Winterhaven soils: occur on lower flood plains; have carbonatic mineralogy and are stratified within a depth of 127 cm (50 in)

DRAINAGE AND PERMEABILITY: Well drained; Permeability is moderate to moderately slow; Runoff is negligible on less than 1 percent slopes and low to medium on 1 to 5 percent slopes.

USE AND VEGETATION: Used mostly for irrigated cropland, rangeland, and wildlife habitat. A few areas are nonirrigated cropland. With retrogression on rangeland, such plants as threeawn, curly mesquite, hooded windmillgrass, Hall's panicum, fall witchgrass, and red grama increase or invade, and are dominant on most areas. A wide array of brush plants also increase and invade such as mesquite, guajillo, condalia, paloverde, guyacan, twisted acacia, whitebrush, and pricklypear.

DISTRIBUTION AND EXTENT: Southern Texas; LRR I; MLRA 83A - Northern Rio Grande Plain. The series is of large extent.

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

SERIES ESTABLISHED: Zavala County, Texas; 1982.

REMARKS:
Edited 11/2016 (RFG-GWH): Added carbonate clay content and calcium carbonate equivalent to range in characteristics. Updated competing series, geographic setting, and associated soils sections.

Diagnostic horizons and features recognized in this pedon are:
Particle-size control section: 25 to 100 cm (10 to 40 in)
Ochric epipedon: 0 to 36 cm (0 to 14 in). (A horizons)
Calcic horizon: 61 to 203 cm (14 to 80 in). (Bk2, Bk3, Bk4, Bk5 horizons)

ADDITIONAL DATA: Pedon data determined by Soil Survey Laboratory, Lincoln, NE; User Pedon ID 79TX507003 (KSSL pedon # 79P0332) from the type location; User Pedon ID 84TX507001 (KSSL pedon # 84P0454).

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

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National Cooperative Soil Survey
U.S.A.