LOCATION HOCKLEY TXEstablished Series
TAXONOMIC CLASS: Fine-loamy, siliceous, semiactive, hyperthermic Plinthic Paleudalfs
TYPICAL PEDON: Hockley fine sandy loam-pasture.
(Colors are for moist soil unless otherwise stated.)
Ap--0 to 5 inches; very dark grayish brown (10YR 3/2) fine sandy loam, grayish brown (10YR 5/2) dry; weak fine granular structure; hard, very friable; many fine pores; many worm casts; neutral; gradual smooth boundary. (4 to 15 inches thick)
E--5 to 23 inches; dark grayish brown (10YR 4/2) fine sandy loam, grayish brown (10YR 5/2) dry; weak coarse subangular blocky structure; hard, very friable; common very fine and fine roots; few very fine tubular pores; 2 percent ironstone pebbles 10 to 15 mm in size; 1 percent fine distinct dark brown (7.5YR 3/4) iron concentrations with sharp boundaries lining pores; neutral; gradual smooth boundary. (16 to 25 inches thick)
Bt--23 to 50 inches; yellowish brown (10YR 5/6) sandy clay loam; yellowish brown (10YR 5/6) dry; weak medium and coarse subangular blocky structure; very hard, friable; few distinct clay films on surfaces of peds and clay bridges between sand grains; 3 percent ironstone pebbles 10 to 15 mm in size; 5 percent fine and medium prominent red (2.5YR 4/6) iron concentrations with sharp boundaries in matrix; 3 percent medium distinct brown (7.5YR 4/3) iron-manganese concentrations with sharp boundaries lining pores; neutral; gradual wavy boundary. (10 to 40 inches thick)
Btvc1--50 to 75 inches; reticulately mottled 60 percent yellowish brown (10YR 5/6), 25 percent red (2.5YR 4/6), and 10 percent gray (10YR 6/1) sandy clay loam; weak and moderate medium subangular blocky structure; extremely hard, friable; common distinct yellowish brown (10YR 5/6) clay films on surfaces of peds and common prominent gray (10YR 5/1) clay films in gray (10YR 6/1) matrix; 2 percent of red (2.5YR 4/6) matrix is brittle; 10 percent medium red (2.5YR 4/8) plinthite; 10 percent ironstone pebbles 10 to 15 mm in size; slightly acid; diffuse wavy boundary. (15 to 35 inches thick)
Btvc2--75 to 100 inches; reticulately mottled 50 percent red (2.5YR 4/6), 40 percent yellowish brown (10YR 5/6), and 10 percent gray (10YR 6/1) sandy clay loam; medium subangular blocky structure; extremely hard, friable; common distinct yellowish brown (10YR 5/6) clay films on surfaces of peds and common prominent gray (10YR 5/1) clay films in gray (10YR 6/1) matrix; 4 percent of red (2.5YR 4/6) matrix is brittle; 5 percent medium red (2.5YR 4/8) plinthite; 3 percent ironstone pebbles 10 to 15 mm in size, decreasing with depth; slightly acid.
TYPE LOCATION: Harris County, Texas; from intersections of Farm Road 149 and Farm Road 2920 in Tomball, 8.1 miles west on Farm Road 2920; 100 feet south of road in pasture. (Latitude 30 degrees, 04 minutes, 30 seconds North; Longitude 95 degrees, 45 minutes, 35 seconds West; USGS Topographic Quad: Hockley, Texas; Projection: NAD 1927)
RANGE IN CHARACTERISTICS: The solum is more than 80 inches thick.
Soil Moisture: An udic soil moisture regime. The soil moisture control section, 4 to 12 inches, is typically moist from September to July in normal years. The cumulative total number of days the soil moisture control section is dry is less than 90 days.
Mean annual soil temperature: 69 to 72 degrees F.
Depth to argillic horizon: 20 to 30 inches
Depth to redox depletions: 48 to 55 inches
Particle-size control section (weighted average)
Clay content: 20 to 30 percent
CEC/clay ratio: 0.25 to 0.40
Ap or A Horizon
Hue: 7.5YR or 10YR
Value: 3 to 5
Chroma: 2 or 3; Pedons with value of 3 and chroma of 2 or 3 are less than 10 inches thick.
Texture: fine sandy loam or loamy fine sand.
Redox concentrations: amount-0 to 2 percent, size-fine, contrast-faint, boundary-sharp, location-lining pores, shades-brown.
Reaction: moderately acid to neutral.
E Horizon
Hue: 7.5YR or 10YR
Value: 4 or 5
Chroma: 2 to 4
Texture: fine sandy loam or loamy fine sand.
Redox concentrations: amount-0 to 3 percent, size-fine, contrast-faint, boundary-sharp, location-lining pores, shades-brown.
Reaction: moderately acid to neutral.
Bt Horizon
Hue: 7.5YR or 10YR
Value: 5 to 7
Chroma: 4 to 6
Texture: fine sandy loam, loam, sandy clay loam.
Clay content: 15 to 22 percent
Clay films: location-surfaces of peds, contrast-faint or distinct.
Redox accumulations: amount 2 to 15 percent, size-fine or medium, contrast-faint to prominent, boundary-sharp, location-lining pores, in matrix, and on surfaces of peds, shades-red, yellow, or brown.
Ironstone nodules: 1 to 15 percent
Reaction: moderately acid to neutral.
Btvc Horizons
Reticulately mottled matrix
Hue: 2.5YR (30 to 60 percent)
Value: 4
Chroma: 6 to 8
Hue: 7.5YR or 10YR (30 to 60 percent)
Value: 5 to 7
Chroma: 4 to 8
Hue: 10YR (10 to 20 percent)
Value: 5 to 7
Chroma: 1 or 2
Texture: sandy clay loam, clay loam, or sandy clay.
Clay content: 20 to 40 percent
Clay films: location-surfaces of peds, contrast-faint or distinct.
Ironstone nodules: 1 to 15 percent
Plinthite nodules: 5 to 12 percent
Reaction: moderately acid to neutral.
COMPETING SERIES: There are no other series in the same family. Similar soils are the
Mockley,
Pinetucky,
Prairieview,
Segno, and
Wockley series.
Mockley series: ultisols; fine particle-size control section
Pinetucky series: ultisols; thermic temperature regime
Prairieview series: Oxyaquic subgroup
Segno series: thermic temperature regime
Wockley series: Plinthaquic subgroup
GEOGRAPHIC SETTING:
Parent material: Loamy sediments derived from the Willis Formation of late Plio-Pleistocene age
Landform: Coastal Plain
Slope: 0 to 5 percent
Mean annual temperature: 67 to 69 degrees F.
Mean annual precipitation: 40 to 48 inches
Precipitation Pattern: Precipitation is fairly uniform throughout the year with slight peaks in the spring and fall. Summer moisture deficit ranges from 0 to 4 inches.
Frost-free period: 240 to 270 days
Elevation: 175 to 250 feet
Thornthwaite annual P-E indices: 62 to 72
GEOGRAPHICALLY ASSOCIATED SOILS: These are the
Mockley,
Prairieview,
Snakecreek,
Tomball, and
Wockley series.
Mockley series: fine particle-size control section and on a similar to higher landscape position
Prairieview series: moderately well drained and on a lower landscape position
Snakecreek series: somewhat poorly drained and on a lower landscape position
Tomball series: poorly drained and in depressions
Wockley series: somewhat poorly drained and on a lower landscape position
DRAINAGE AND PERMEABILITY: Well drained. Moderate permeability. Runoff is negligible on 0 to 1 percent slopes; low on 1 to 5 percent slopes.
USE AND VEGETATION: Used mainly as pastureland and cropland. Urban encroachment is common in the eastern portion of this series' extent. The dominant pasture grass is improved coastal bermudagrass. The dominant crop is corn. Native grasses are species of andropogons, paspalums, and panicums. Pine trees have encroached on many areas.
DISTRIBUTION AND EXTENT: Southeastern Texas; mainly east of the Colorado River along the interior margin of the Coastal Prairie; LRR T; MLRA 150A; large extent.
MLRA OFFICE RESPONSIBLE: Temple, Texas.
SERIES ESTABLISHED: Harris County, Texas, 1922.
REMARKS:
Diagnostic horizons and features recognized in this pedon are:
Particle size control section: 23 to 43 inches. (Bt horizon)
Ochric epipedon: 0 to 23 inches. (A and E horizons)
Argillic horizon: 23 to 100 inches. (Bt, Btvc1, Btvc2 horizons)
More than 5 percent plinthite: 5 to 100 inches (Btv1 and Btvc2 horizons)
Additional Comments: This series recognizes graded phases.
The assignment of the cation-exchange activity class is supported by laboratory data number S00TX-473-1 from Waller County, Texas.
The mineralogy is supported by laboratory data on sample 72TX-101-3 (72L107).
ADDITIONAL DATA: Laboratory data from the Texas A&M University Soil Characterization Lab on sample S00TX-473-1 and the National Soil Survey Lab on sample 72TX-101-3 (72L107)
TAXONOMIC VERSION: Soil Taxonomy, Second Edition, 1999