LOCATION KATY               TX

KATY SERIES

TAXONOMIC CLASS: Fine-loamy, siliceous, active, hyperthermic Oxyaquic Paleudalfs

TYPICAL PEDON: Katy fine sandy loam--pasture (Colors are for moist soil unless otherwise stated.)

Ap--0 to 30 cm (0 to 12 in); dark grayish brown (10YR 4/2) fine sandy loam, grayish brown (10YR 5/2) dry; massive; soft, very friable; many very fine roots; common very fine and fine interstitial and tubular pores; strongly acid; gradual smooth boundary. (13 to 38 cm [5 to 15 in] thick)

E--30 to 63 cm (12 to 25 in); pale brown (10YR 6/3) fine sandy loam, very pale brown (10YR 7/3) dry; massive; soft, very friable; many very fine tubular pores; 1 percent fine prominent yellowish brown (10YR 5/8) iron accumulations with sharp boundaries lining pores; strongly acid; clear wavy boundary. (23 to 56 cm [9 to 22 in] thick)

Bt1--63 to 71 cm (25 to 28 in); yellowish brown (10YR 5/6) loam, brownish yellow (10YR 6/6) dry; weak medium subangular blocky structure; moderately hard, friable; common very fine roots; common very fine tubular pores; 5 percent faint yellowish brown (10YR 5/6) clay films on surfaces of peds; 3 percent fine distinct reddish yellow (7.5YR 6/8) iron accumulations on surfaces of peds and 2 percent fine prominent yellowish red (5YR 5/6) iron accumulations on surfaces of peds; moderately acid; clear smooth boundary. (combined thickness of the Bt horizons is 127 to 158 cm [50 to 62 in])

Bt2--71 to 117 cm (28 to 46 in); 60 percent yellowish brown (10YR 5/6) and 25 percent red (2.5YR 4/8) and 15 percent gray (10YR 5/1) loam, 60 percent brownish yellow (10YR 6/6) and 25 percent red (2.5YR 5/8) and 15 percent gray (10YR 6/1) dry; moderate medium subangular blocky structure; very hard, friable; common very fine roots; common very fine tubular pores; 25 percent prominent very dark gray (10YR 3/1) clay films on surfaces of peds; 1 percent fine distinct spherical black (10YR 2/1) iron-manganese concretions; slightly acid; gradual wavy boundary.

Bt3--117 to 163 cm (46 to 64 in); 50 percent yellowish brown (10YR 5/6) and 30 percent red (2.5YR 4/8) and 20 percent gray (10YR5/1) loam, 50 percent yellowish brown (10YR 5/6) and 30 percent red (2.5YR 5/8) and 20 percent gray (10YR 6/1) dry; weak coarse prismatic structure parting to moderate coarse subangular blocky structure; very hard, firm; common very fine roots between peds; few very fine tubular pores; 10 percent distinct dark gray (10YR 4/1) clay films on surfaces of peds and 5 percent prominent sand coats on vertical surfaces of peds; neutral; gradual wavy boundary.

Bt4--163 to 203 cm (64 to 84 in); 50 percent brownish yellow (10YR 6/6) and 25 percent gray (10YR 6/1) and 25 percent red (2.5YR 4/8) clay loam, 50 percent brownish yellow (10YR 6/6) and 25 percent gray (10YR 6/1) and 25 percent red (2.5YR 5/8) dry; moderate coarse prismatic structure parting to moderate coarse subangular blocky structure; very hard, very firm; few very fine roots; few very fine tubular pores; 20 percent distinct gray (10YR 5/1) clay films on surfaces of peds and 5 percent distinct sand coats on vertical surfaces of peds; neutral.

TYPE LOCATION: Fort Bend County, Texas; from the intersection of Farm Road 1093 and Farm Road 359 in Fulshear; 3.3 miles east on Farm Road 1093 to the intersection of Farm Road 1463; 0.1 mile north on Farm Road 1463; 300 feet east in pasture; Latitude: 29 degrees, 41 minutes, 42.71 seconds N; Longitude: 95 degrees, 50 minutes, 43.14 seconds W. Richmond NE topographic quadrangle; NAD 83.

RANGE IN CHARACTERISTICS:
Soil Moisture: An udic soil moisture regime. The soil moisture control section is from 10 to 61 cm (4 to 24 in) in depth. These soils remain moist in some part of the soil moisture control section for more than 275 days in normal years, with rainfall being fairly uniform throughout the year. Typically, March is the driest month.

Mean annual soil temperature: 22 to 23 degrees C (71.5 to 72.5 degrees F)
Depth to argillic horizon: 46 to 76 cm (18 to 30 in)
Depth to redox concentrations: 13 to 43 cm (5 to 17 in)
Depth to episaturation: 13 to 76 cm (5 to 30 in)
Thickness of the A and E horizons: 46 to 76 cm (18 to 30 in)

Particle-size control section (weighted average)
Clay content: 25 to 30 percent
Sand content: 35 to 45 percent
CEC/clay ratio: 0.40 to 0.55

A horizon
Hue: 10YR
Value: 4 or 5
Chroma: 2 or 3
Texture: fine sandy loam, very fine sandy loam, or loam
Clay content: 5 to 15 percent
Iron accumulations: amount- 0 to 3 percent, size- fine or medium, contrast- distinct or prominent, boundary- diffuse, clear or sharp, location- in matrix, lining of pores or on surfaces of peds, color-shades of brown (Iron accumulations are associated with pedons in rice culture.)
Base saturation: 50 to 75 percent
Reaction: strongly acid to moderately acid (pH 5.1 to 6.0)

E horizon
Hue: 10YR
Value: 4 to 6
Chroma: 3 or 4
Texture: fine sandy loam, very fine sandy loam, or loam
Clay content: 6 to 14 percent
Iron accumulations: amount- 1 to 4 percent, size- fine to coarse, contrast distinct or prominent, boundary- diffuse, clear or sharp, location- in matrix, lining of pores or on surfaces of peds, color- shades of brown, red or yellow
Iron depletions: amount- 2 to 8 percent, size- fine to coarse, contrast- faint or prominent, boundary- diffuse, location- in matrix or surfaces of peds, color- shades of brown or gray
Base saturation: 50 to 70 percent
Reaction: strongly acid to slightly acid (pH 5.1 to 6.5)

Bt horizon (Upper part)
Hue: 10YR
Value: 4 to 6
Chroma: 2 to 4 (chroma of 2 is considered relict wetness)
Texture: Loam or sandy clay loam
Clay content: 20 to 30 percent
Iron accumulations: amount- 1 to 10 percent, size- fine to coarse, contrast- distinct or prominent, boundary-clear or sharp, location- in matrix or lining pores, color- shades of brown, red or yellow
Redox depletions: amount-0 to 5 percent, size- fine or medium, contrast- faint or distinct, boundary- sharp, location- in matrix, color- shades of gray (depletions are considered relict)
Base saturation: 60 to 80 percent
Reaction: moderately acid to slightly acid (pH 5.6 to 6.5)

Bt horizon (Lower part)
Variegated matrix
These matrix colors make up 50 to 80 percent of the horizon:
Hue: 2.5YR, 5YR, or 7.5YR
Value: 4 to 6
Chroma: 4 to 8
These colors make up 20 to 50 percent of the horizon:
Hue: 10YR
Value: 5 or 6
Chroma: 1 or 2 (These colors are considered relict wetness)
Texture: clay loam
Clay content: 27 to 35 percent
Iron accumulations: variegated matrix is comprised of medium or coarse iron accumulations
Base saturation: 75 to 90 percent
Reaction: slightly acid to neutral (pH 6.1 to 7.3)

COMPETING SERIES: There are no series in the same family. Similar soils are the Cheetham, Glenwild, Prairieview, and Wockley series.
Cheetham soils: plinthite within 152 cm (60 in) of the soil surface and have a loamy sand surface.
Glenwild soils: are Hapludalfs, have a fine-silty particle-size control section, a superactive CEC to clay class, and mixed mineralogy class.
Prairieview soils: have plinthite and a semiactive CEC to clay class.
Wockley soils: have a Plinthaquic subgroup and a semiactive CEC to clay class.

GEOGRAPHIC SETTING:
Parent material: Loamy sediments derived from the Lissie Formation
Landform: Coastal Plain
Slope: 0 to 3 percent
Mean annual air temperature range: 20 to 21.1 degrees C (68 to 70 degrees F)
Mean annual precipitation range: 102 to 122 cm (40 to 48 in)
Precipitation Pattern: Rainfall is fairly uniform throughout the year. Typically, March is the driest month.
Frost-free period: 270 to 330 days
Elevation: 100 to 155 feet
Thornthwaite annual P-E indices: 62 to 70

GEOGRAPHICALLY ASSOCIATED SOILS: These are the Addicks, Clodine, tentative Cyfair, Garwood, Gessner and Telf series.
Addicks soils: are mollisols.
Clodine soils: have a coarse-loamy particle-size class, are grayer throughout, and are on a lower landscape position
Cyfair soils: are somewhat poorly drained and are on a slightly lower landscape position
Garwood and Telf soils: have an abrupt texture change and are on a similar landscape position
Gessner soils are poorly drained and are in depressions

DRAINAGE AND PERMEABILITY: Moderately well drained. Permeability is moderately slow. Runoff is very low on 0 to 1 percent slopes and low on 1 to 3 percent slopes. A perched water table is in the E horizon for short periods during the cool months or in periods of excess rainfall.

USE AND VEGETATION: Used for crop production, mainly rice production, and for livestock grazing. Some areas are used for growing corn and grain sorghum. Native grasses consist of little bluestem, indiangrass, big bluestem, switchgrass, crinkleawn, and Florida paspalum. A few areas near the eastern limit of the extent have pine forest encroachment and many areas have urban development.

DISTRIBUTION AND EXTENT: Gulf Coast Prairies (MLRA 150A in LRR T) of Southeast Texas, mainly from the Brazos River to the San Jacinto River. The series is of 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: 64 to 114 cm (25 to 45 in). (Bt1 and Bt2 horizon)
Ochric epipedon: 0 to 64 cm (0 to 25 in). (A and E horizons)
Argillic horizon: 64 to 203 cm (25 to 80 in). (Bt horizons)
Iron accumulations: 31 to 203 cm (12 to 80 in). (E, Bt1, Bt2, and Bt3 horizons)
Episaturation: The zone of saturation at 31 to 112 cm (12 to 44 in). (E and Bt1 horizons)
Oxyaquic feature- These soils become saturated but not reduced in upper 75 centimeters of the mineral soil surface.
Pale feature- Clay does not decrease by as much as 20 percent absolute from the maximum clay content within 60 inches of the soil surface.

Additional Comments: Classification change from thermic to hyperthermic temperature regime is based on geographic distribution of the series. In January 2003, classification was changed from an Aquic to Oxyaquic subgroup. This change was based on soil moisture monitoring data collected on soils in the area.
The assignment of the cation-exchange activity class is supported by laboratory data number S55TX-157-093 from the series type location in Fort Bend County.

ADDITIONAL DATA: National Soil Survey Laboratory soil characterization data exists on pedon 40A4455 (S55TX-157-093) from the type location in Fort Bend County, Texas.

TAXONOMIC VERSION: Keys to Soil Taxonomy, Tenth Edition, 2006