LOCATION SHIRO TXEstablished Series
TAXONOMIC CLASS: Fine, mixed, active, thermic Udic Paleustalfs
TYPICAL PEDON: Shiro loamy fine sand on a 3 percent slope, in woodland. (Colors are for dry soils unless otherwise noted.)
A--0 to 6 inches; pinkish gray (7.5YR 7/2) loamy fine sand, pinkish gray (7.5Y 6/2) moist; single grained; loose; many medium roots; moderately acid; clear smooth boundary. (3 to 8 inches thick)
E--6 to 12 inches; pinkish white (7.5YR 8/2) loamy fine sand, pinkish gray (7.5YR 6/2) moist; single grained; hard; loose; many medium roots; moderately acid; abrupt smooth boundary. (4 to 14 inches thick)
Bt1--12 to 18 inches; reddish yellow (5YR 6/6) clay, yellowish red (5YR 5/6) moist; common fine faint light brownish gray (10YR 6/2) redox depletions; weak coarse prismatic structure parting to moderate medium subangular blocky; extremely hard, extremely firm; sticky and plastic; many fine roots; few clay films on faces of peds; very strongly acid; clear smooth boundary.
Bt2--18 to 24 inches; light gray (10YR 7/1) clay, gray (10YR 6/1) moist, common medium prominent red (2.5YR 4/6) redox concentrations; moderate medium prismatic structure parting to medium subangular blocky; extremely hard, extremely firm; sticky and plastic; few fine roots; few thin clay films on faces of peds; common fine masses of barite; very strongly acid; clear smooth boundary.
Bt3--24 to 31 inches; light gray (10YR 7/1) clay, gray (10YR 6/1) moist; moderate coarse subangular blocky structure; extremely firm; sticky and plastic; few fine roots; few thin clay films on faces of peds; common fine masses barite; very strongly acid; abrupt smooth boundary. (combined Bt subhorizons 16 to 30 inches thick)
Cr--31 to 40 inches; white (2.5Y 8/2) weakly cemented sandstone; common medium distinct reddish yellow (7.5YR 6/6) redox concentrations; very strongly acid.
TYPE LOCATION: Grimes County, Texas; from the intersection of State Highway 30 and State Highway 90 in Roan's Prairie 2.1 miles east-northeast on Highway 30 to intersection with county road, south 1.3 miles on county road, site is 50 feet west of road in wooded rangeland.
RANGE IN CHARACTERISTICS: Solum thickness and depth to paralithic contact ranges from 20 to 40 inches. Thickness of the combined A and E horizons ranges from 10 to 18 inches. Clay content of the upper 20 inches of the argillic horizon ranges from 35 to 45 percent. Redoximorphic features are considered lithochromic and/or relic. They do not appear to be related to the present moisture conditions in the soil.
The A horizon has a hue of 7.5YR or 10YR, value of 5 to 6, and chroma of 2 or 3. Texture is loamy fine sand or loamy sand. Reaction ranges from strongly acid to slightly acid.
The E horizon has hue of 7.5YR or 10YR, value of 5 to 8, and chroma of 2 or 3. Reaction ranges from strongly acid to slightly acid.
The upper part of the Bt horizon has hue of 2.5YR to 10YR, value of 4 or 7, and chroma of 4 to 6. Texture is clay, sandy clay, or clay loam. Reaction is very strongly acid to moderately acid.
The lower and middle part of the Bt horizon has hue of 10YR, value of 5 to 7, and chroma of 1 or 2. Redox concentrations range from few to many in shades of red, yellow, or brown. Reaction ranges from very strongly acid to neutral.
The Cr horizon is weakly to strongly cemented tuffaceous sandstone or siltstone that is interbedded with shale. Fractures are spaced 1 to 3 feet apart, and roots are restricted to the fractures.
COMPETING SERIES: These include the Callisburg, Chaney, Chigley, Cona, Edge, Minwells, Truce, Windthorst, and Straber series. These soils do not have a paralithic contact of sandstone. In addition they have a solum thicker than 40 inches.
GEOGRAPHIC SETTING: Shiro soils are on nearly level to moderately sloping uplands. Slope gradients range from 0 to 8 percent. The soils formed from tuffaceous sandstones, siltstones, mudstones and shales of the Catahoula formation and the associated Jackson Group. The climate is warm subhumid. The mean annual temperature ranges from 66 to 70 degrees F, and mean annual precipitation ranges form 35 to 40 inches. Frost free days range from 260 to 280 days and elevation ranges from 250 to 550 feet. Thornthwaite P-E indices ranges from 50 to 68.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the Arol, Burlewash, Elmina, Koether, Lufkin, Oakhurst and Singleton soils. Arol soils have montmorillonitic mineralogy and a Bt horizon with color value less than 3.5. Arol in slightly lower positions. Burlewash, Elmina, Gomery, Koether, and Rosenwall soils are above on ridges and side slopes. Elmina and Gomery soils have arenic epipedons. Koether soils contain more than 35 percent coarse fragments and are on similar or slightly higher positions. Lufkin and Oakhurst soils do not have paralithic contacts. The Arol, Lufkin and Oakhurst soils are on lower positions.
DRAINAGE AND PERMEABILITY: Well drained. Permeability is slow. Runoff is low on 0 to 1 percent slopes, medium on 1 to 5 percent slopes and high on 5 to 8 percent slopes.
USE AND VEGETATION: Most areas are in pasture, but a few areas are farmed to small grains and forage sorghums. Native vegetation includes an overstory of post oak, blackjack oak, with an understory of little bluestem, purpletop, brownseed paspalum, indiangrass, low panicums, shrubs and forbs. Pine trees have encroached on some areas.
DISTRIBUTION AND EXTENT: The Shiro series is mainly distributed in east and east-central Texas. The series is of moderate extent.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Temple, Texas
SERIES ESTABLISHED: Grimes County, Texas, 1988.
REMARKS: These soils have formerly been included in the Chazos and Elmina series.
Diagnostic horizons and features recognized in this pedon are:
Ochric epipedon - 0 to 12 inches
Argillic horizon - 12 to 31 inches
Abrupt textural change from E horizon to Bt horizon
Paralithic contact - tuffaceous sandstones, siltstones, and shales at 31 inches.
ADDITIONAL DATA: Characterization data from TAMU - S83TX-185-3.