LOCATION HILGRAVE TX
Established Series
Rev. CLG-GSF-WJG-ROG
09/2020
HILGRAVE SERIES
The Hilgrave series consists of deep, well drained and moderately permeable gravelly soils that formed in ancient gravelly alluvium. These soils are on moderately sloping to strongly sloping uplands. Slopes range from 3 to 30 percent. Mean annual precipitation is about 559 mm (22 in) and the mean annual temperature is about 17 degrees C (62 degrees F).
TAXONOMIC CLASS: Loamy-skeletal, mixed, semiactive, thermic Aridic Haplustalfs
TYPICAL PEDON: Hilgrave very gravelly sandy loam-pasture. (Colors are for dry soil unless otherwise stated.)
A--0 to 18 cm (0 to 7 in); reddish brown (2.5YR 4/4) very gravelly sandy loam, dark reddish brown (2.5YR 3/4) moist; weak granular structure; soft, very friable; many very fine roots and pores; contains 60 percent by volume siliceous gravel; neutral; clear smooth boundary. (Thickness is 13 to 24 cm [5 to 10 in]).
Bt1--18 to 41 cm (7 to 16 in); red (2.5YR 5/6) extremely gravelly loam, red (2.5YR 4/6) moist; weak subangular blocky structure; soft, friable; common very fine roots and pores; clay bridging between sand grains; contains 65 percent by volume siliceous gravel; neutral; gradual smooth boundary. (Thickness is 10 to 36 cm [4 to 14 in]).
Bt2--41 to 66 cm (16 to 26 in); red (2.5YR 5/6) extremely gravelly sandy clay loam, dark red (2.5YR 4/6) moist; weak subangular blocky structure; slightly hard, friable; few very fine roots and pores; evident clay films and bridging between sand grains; contains 75 percent by volume siliceous gravel; moderately alkaline; abrupt smooth boundary. (Thickness is 15 to 31 [6 to 12 in]).
Bk--66 to 102 cm (26 to 40 in); red (2.5YR 5/6) gravelly loamy sand, (2.5YR 4/6) moist; massive; soft, very friable; few very fine roots and pores; contains 30 percent siliceous gravel, by volume, in upper part grading to 52 percent in lower part; few very fine films and threads of calcium carbonate; some pebbles have thin coatings of calcium carbonate; strong effervescence, moderately alkaline; abrupt wavy boundary. (Thickness is 15 to 46 cm [6 to 18 in]).
C--102 to 152 cm (40 to 60 in); reddish yellow (5YR 6/6) coarse sand, yellowish red (5YR 4/6) moist; massive; soft, very friable; few gravels; moderately alkaline.
TYPE LOCATION: Cottle County, Texas; approximately 12 miles (airline) northwest of Paducah on the Matador Wildlife Refuge. The pedon site is 30 feet west of the ranch road and 1.3 miles, via ranch road, southwest of the windmill that is beside the ranch road; this location is 12.9 miles west of the Matador Wildlife Refuge Headquarters along the ranch road. Latitude: 34 degrees, 7 minutes, 25.89 seconds N; Longitude: 100 degrees, 27 minutes, 4.09 seconds W. WGS84.
RANGE IN CHARACTERISTICS:
Thickness of the solum ranges from 51 to 127 cm (20 to 50 in). Depth to soft powdery secondary lime ranges from 41 to 71 cm (16 to 28 in). Gravel content ranges from 35 to 80 percent in at least the upper 51 cm (20 in) of the Bt horizon, and usually throughout the solum.
Soil Moisture: Typic-ustic soil moisture regime.
Mean annual soil temperature: 13.9 to 18.9 degrees C (57 to 66 degrees F)
A Horizon
Hue: 2.5YR to 7.5RY
Value: 5 to 6
Chroma: 3 to 4
Texture: extremely gravelly sandy loam to gravelly loam
Reaction: medium acid to moderately alkaline, but noncalcareous.
Bt Horizon
Hue: 2.5YR to 5YR
Value: 4 to 5
Chroma: 3 to 6
Texture: very gravelly or extremely gravely sandy loam to very gravelly or extremely gravely sandy clay loam.
Reaction: slightly acid to moderately alkaline, but noncalcareous in the upper part.
Bk Horizon:
Reaction: noncalcareous to calcareous in the matrix, with segregated calcium carbonate in the form of films and threads or coatings of calcium carbonate on the pebbles.
Rock fragments: gravel-free sand to highly stratified gravel beds, containing strata of reddish earth.
COMPETING SERIES: There are no other soils in this family. Soils in similar families are the
Devol,
Gallegos,
Grandfield,
Miles,
Mobeetie,
Polar, and
Springer series.
Devol,
Grandfield,
Miles, and
Springer soils have less than 35 percent gravel in the Bt horizon.
Gallegos and
Polar soils lack a Bt horizon, Polar soils have a calcic horizon.
Mobeetie soils are calcareous throughout, lack a Bt horizon, and gravel content is less than 35 percent in the 25 to 102 cm (10 to 40 in) of the control section.
GEOGRAPHIC SETTING:
Parent Material: The soils developed in stratified outwash resting on clean sands or gravel beds, ancient gravelly alluvium.
Landscape: Dissected plains
Landform: Hillslope
Slope: 3 to 30 percent
Mean annual precipitation: 457 to 660 mm (18 to 26 in)
Mean annual air temperatures: 14 to 19 degrees C (57 to 66 degrees F) Thornthwaite annual P-E indices of about 24 to 40.
Frost-free period: 210 to 230 days.
Elevation: 411.5 to 487.6 meters (1350 to 1600 feet)
GEOGRAPHICALLY ASSOCIATED SOILS: These are the
Miles and
Springer series.
DRAINAGE AND PERMEABILITY:
Drainage class: Well
Permeability: moderate
Runoff: medium to rapid
USE AND VEGETATION:
Major uses: rangeland
Native vegetation:the principal grasses are little bluestem and sand dropseed, with some sideoats, blue grama, black grama, and threeawn. Sand sagebrush, cacti, juniper trees, mesquite trees, and yucca shrub also grow on these soils. Many gravel pits are in some areas.
Ecological sites assigned to phases and components of this series are listed below. Current ecological site assignments are in Web Soil Survey
DISTRIBUTION AND EXTENT:
General location: Rolling Plains areas of west central Texas and possibly in similar areas of Oklahoma. Small extent.
SOIL SURVEY REGIONAL OFFICE (SSRO) RESPONSIBLE: Temple, Texas
SERIES ESTABLISHED: Cottle County, Texas; 1970.
REMARKS: Previously mapped as a miscellaneous land type, hilly gravelly land.
Diagnostic horizons and features recognized in this pedon are:
Ochric epipedon - 0 to 18 cm (0 to 7 inches)
Argillic horizon - 18 to 66 cm (7 to 26 in)
Taxonomic Version: Keys to Soil Taxonomy, Twelfth Edition, 2014
National Cooperative Soil Survey
U.S.A.