LOCATION CHAZOS TXEstablished Series
TAXONOMIC CLASS: Fine, smectitic, thermic Udic Paleustalfs
TYPICAL PEDON: Chazos loamy fine sand--pasture. (Colors are for moist soil unless otherwise stated).
A--0 to 6 inches; dark brown (10YR 4/3) loamy fine sand, light yellowish brown (10YR 6/4) dry; weak fine granular structure; slightly hard, friable; common fine roots; common fine pores; few fine and medium rounded siliceous pebbles; slightly acid; clear smooth boundary.
E--6 to 15 inches; yellowish brown (10YR 5/4) loamy fine sand, very pale brown (10YR 7/4) dry; single grained; slightly hard, very friable; common fine roots; common fine pores; few fine and medium rounded siliceous pebbles; slightly acid; abrupt wavy boundary. (combined thickess of the A and E horizons is 10 to 20 inches)
Bt1--15 to 22 inches; red (2.5YR 4/8) clay, red (2.5YR 5/8) dry; moderate medium prismatic structure parting to moderate medium angular blocky; very hard, very firm; few fine roots; few fine pores; few pressure faces; few thin clay films on surfaces of prisms; few iron-manganese concretions; few fine rounded siliceous pebbles; common fine and medium distinct brownish yellow (10YR 6/6) masses of iron accumulation; and pale brown (10YR 6/3) iron dpeletions; moderately acid; gradual wavy boundary. (6 to 18 inches thick)
Bt2--22 to 29 inches; dark yellowish brown (10YR 4/4) clay loam, yellowish brown (10YR 5/4) dry; moderate medium prismatic structure parting to coarse angular blocky; very hard, very firm; few fine roots; few fine pores; few pressure faces; few thin clay films on surfaces of prisms; few iron-manganese concretions; few fine rounded siliceous pebbles; many fine and medium prominent yellowish red (5YR 5/8) masses of iron accumulation, and common fine faint brown (10YR 5/3) iron depletions; moderately acid; diffuse wavy boundary. (9 to 20 inches thick)
Bt3--29 to 34 inches; dark grayish brown (2.5Y 4/2) clay loam; moderate medium prismatic structure parting to weak coarse angular blocky; very hard, very firm; few fine roots; few fine pores; few pressure faces; few thin clay films on surfaces of prisms; common fine iron-manganese concretions; common medium distinct dark yellowish brown (10YR 4/4), and few fine prominent red (2.5YR 4/6) masses of iron accumulation; common medium distinct light brownish gray (10YR 6/2) iron depletions; slightly acid; diffuse smooth boundary. (0 to 15 inches thick)
Btk--34 to 47 inches; light olive brown (2.5Y 5/3) sandy clay loam, moderate medium prismatic structure parting to weak coarse subangular blocky; very hard, firm; few fine roots; few fine pores; few thin clay films on surfaces of prisms; 3 percent fine concretions of calcium carbonate; common fine iron-manganese concretions; few siliceous pebbles; common medium and coarse distinct yellowish brown (10YR 5/4) masses of iron accumulation; slightly effervescent; moderately alkaline; gradual smooth boundary. (0 to 20 inches thick)
BCt1--47 to 65 inches; light yellowish brown (2.5Y 6/3) sandy clay loam; moderate medium prismatic structure parting to weak coarse subangular blocky; very hard, firm; few fine roots; few fine pores; common patchy clay films on surfaces of peds; few fine concretions of calcium carbonate; few fine siliceous pebbles; few medium prominent brown (7.5YR 5/4) and few fine prominent red (2.5YR 4/6) masses of iron accumulation; slightly alkaline; gradual boundary. (10 to 35 inches thick)
2BCt2--65 to 80 inches; reddish brown (5YR 5/4) silty clay loam; weak medium subangular blocky structure; very hard, firm; few fine roots; few fine and medium pores; common patchy clay films on surfaces of peds; few fine iron-manganese stains and concretions; few fine distinct red (2.5YR 4/6) masses of iron accumulation; moderately alkaline.
TYPE LOCATION: Falls County, Texas; from the intersection of Texas Highway 7 and Texas Highway 6 bypass in Marlin; 1.3 miles south on Texas Highway 6; 200 feet west in rangeland. (Latitude: 31 degrees, 17 minutes, 10 seconds N; Longitude: 96 degrees, 52 minutes, 30 seconds W).
RANGE IN CHARACTERISTICS: Solum thickness is 60 to more than 80 inches. Rounded siliceous pebbles range from none to about 5 percent throughout the solum. The combined thickness of the A and E horizons ranges from 10 to 20 inches.
The A horizon has hue of 7.5YR or 10YR, value of 4 or 5, and chroma of 2 to 4. Texture is loamy sand or loamy fine sand. Reaction ranges from moderately acid to neutral.
The E horizon has hue of 7.5YR or 10YR, value 5 to 7, and chroma 2 to 4. Texture is loamy sand or loamy fine sand. Reaction ranges from moderately acid to neutral.
The Bt1 and Bt2 horizons have mixed colors with hue of 2.5YR to 10YR, value of 4 to 6, and chroma of 4 to 8. Redoximorphic features in shades of red, brown, gray, and yellow range from few to many. Other pedons have a mixed matrix. Some pedons have hue of 10YR, value 5 to 7, and chroma of 1 or 2 with many redox concentrations. Texture is clay loam, sandy clay, or clay with clay content ranging from 35 to 50 percent. Reaction is strongly acid to slightly acid.
The lower Bt horizons have hue of 10YR or 2.5Y, value of 4 to 7, and chroma of 2 to 6. Redoximorphic features in shades of red, brown, yellow, and gray range from common to many. Some pedons have a mixed matrix of these colors. Texture is sandy clay loam, clay loam, or sandy clay with clay content ranging from 27 to 40 percent. Some pedons have a few streaks of glossic material in the lower part. Reaction ranges from strongly acid to neutral.
The Btk horizon, if present, has colors in shades of brown with or without iron accumulations of yellow and red. Calcium carbonate in the form of threads, masses, and concretions range from 1 to about 4 percent by volume. The reaction is slightly alkaline or moderately alkaline.
The BCt horizon has colors mainly in shades of gray or brown with or without red or yellow redox concentrations. Texture is sandy clay loam, clay loam, and sandy clay. Reaction ranges from slightly acid to moderately alkaline. Concretions or masses of calcium carbonate range from none to few.
The 2BCt or BC horzons, if present, have color mainly in shades of brown, yellow, red, and olive with or without redoximorphic features. Texture is sandy clay loam, silt loam or silty clay loam. Some pedons have layers stratified with layers of fine sandy loam or sandy clay loam and weakly consolidated sandstone. Reaction is slightly alkaline or moderately alkaline.
COMPETING SERIES: These are the Arol, Gredge, Payne, Singleton, and Zack series. Similar soils include the Axtell, Cadell, Chaney, Fett, Straber and Tabor series. Arol, Singleton, and Zack soils have sola between 20 and 40 inches. Gredge soils have A and E horizons that average less than 10 inches thick. Payne soils do not have an abrupt textural change between the epipedon and argillic horizon. Axtell and Tabor soils have vertic properties. Cadell soils have sola 40 to 60 inches thick. Chaney and Straber soils have mixed mineralogy. Fett soils have a clayey-skeletal control section.
GEOGRAPHIC SETTING: Chazos soils are on nearly level to moderately sloping Pleistocene stream terraces. They are typically 50 to 150 feet above present flood plains. Slopes range from 0 to 8 percent. The soil formed in loamy and clayey sediments. Mean annual temperature ranges from 66 to 69 degrees F., and mean annual precipitation ranges from 35 to 40 inches. Frost free days range from 240 to 275 days and elevation ranges from 200 to 450 feet. Thornthwaite P-E indices range from 52 to 66.
GEOGRAPHICALLY ASSOCIATED SOILS: These include the competing Axtell and Tabor series, and the Padina, Silawa, Silstid, and Tremona series. Padina soils have sandy surface layers more than 40 inches thick. Silstid and Silawa soils have fine-loamy control sections. Also, Silstid and the Tremona soils have an arenic epipedon. Padina, Silstid and Tremona soils are slightly higher in the landscape. Axtell, Silawa, and Tabor soils are on about the same or slightly lower positions in the landscape.
DRAINAGE AND PERMEABILITY: Moderately well drained. Permeability is slow. Runoff is low on slopes less than 1 percent, 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 peanuts, sorghums, and small grain. Native vegetation includes an overstory of post oak and blackjack oak, with an understory of little bluestem, purpletop, beaked panicum, brownseed paspalum, Indiangrass, and low panicums.
DISTRIBUTION AND EXTENT: The series is mainly in the Southern Claypan Area of Texas (MLRA 87A) along terraces of rivers and large streams or remnants of terraces associated with uplands. The series is of moderate extent.
MLRA OFFICE RESPONSIBLE: Temple, Texas
SERIES ESTABLISHED: Falls County, Texas; 1976.
REMARKS: Classification changed (11/91) from mixed mineralogy to montmorillonitic mineralogy based on TAMU data from the series type location in Falls County and the typifying pedons in Milam, McLennan and Brazos Counties, Texas. Classification changed (4/93) from Aquic subgroup to Udic subgroup based on changes in aquic soil definitions and moisture data from similar soils.
Diagnostic horizons and features recognized in this pedon are:
Ochric epipedon - 0 to 15 inches. (A and E horizons)
Argillic Horizon - 15 to 80 inches. (Bt, Btk, BCt, and 2BCt
horizons)
Redoximorphic features - 15 to 80 inches.
Soil Interpretation Record: TX0552