LOCATION SWEETWATER TX+KS OKEstablished Series
TAXONOMIC CLASS: Fine-loamy over sandy or sandy-skeletal, mixed, superactive, calcareous, thermic Fluvaquentic Endoaquolls
TYPICAL PEDON: Sweetwater silty clay loam--native meadow.
(Colors are for dry soil unless otherwise stated.)
A1--0 to 14 inches; dark gray (10YR 4/1) silty clay loam, very dark gray (10YR 3/1) moist; few very fine distinct dark yellowish brown mottles; moderate fine granular structure; very hard, friable; many roots; calcareous; moderately alkaline; clear smooth boundary. (10 to 24 inches thick)
A2--14 to 24 inches; grayish brown (2.5Y 5/2) clay loam, dark grayish brown (2.5Y 4/2) moist; a few fine distinct yellowish brown (10YR 5/6) mottles; weak fine granular and very fine subangular blocky structure; very hard, friable; many roots; calcareous, moderately alkaline; gradual smooth boundary. (0 to 15 inches thick)
C--24 to 60 inches; very pale brown (10YR 7/3) loamy fine sand, pale brown (10YR 6/3) moist, common coarse distinct dark yellowish brown (10YR 4/4) mottles; structureless; slightly hard, very friable; few very thin strata of grayish brown fine sandy loam; calcareous; moderately alkaline.
TYPE LOCATION: Hemphill County, Texas; one mile east of the junction of U. S. Highway 60 and F. M. Road 2266, on F. M. Road 2266 and 750 feet south of F. M. Road 2266; the U. S. Highway 60 and F. M. Road 2266 intersection is on the north side of the Canadian River about 2 miles north of the center of the town of Canadian.
RANGE IN CHARACTERISTICS: Thickness of the soil above the sandy C horizon ranges from 16 to 30 inches. The mollic epipedon is less than 24 inches thick and normally coincides with the A1 horizon. The upper 6 to 20 inches of the 10 to 40 inch control section range from 18 to 35 percent clay and more than 15 percent fine and coarser sand; the lower 10 to 24 inches average sand or loamy fine sand.
The A1 horizon has value of 3 to 5 and chroma of neutral or 1. The A2 horizon, when present, has value of 4 to 6 and chroma of 1 or 2. The A horizons are silt loam, sandy clay loam, silty clay loam or clay loam. The A1 horizon ranges from mildly to moderately alkaline, and some pedons are noncalcareous in the upper 10 inches. The A2 horizon contains faint to distinct yellowish brown mottles.
The C horizon has hue of 10yr or 2.5y, value of 5 to 7 and chroma of 2 to 4. Mottles range from faint to distinct. It is dominantly loamy fine sand, but it contains thin strata ranging from fine sandy loam to silty clay. Buried darkened layers occur in some pedons.
COMPETING SERIES: There are no other series in this family. Similar soils are Colorado, Elsmere, Gageby, Lincoln, Spur, Wann, Yahola, and Yomont series. None of these series have contrasting textures within the control section. With the exception of the Elsmere and Wann series, the series are well drained. In addition, Colorado, Lincoln, Yahola, and Yomont soils lack a mollic epipedon. Elsmere and Wann soils have a mean annual soil temperature less than 59 degrees F. and are dry in some part of the moisture control section for longer periods during the year.
GEOGRAPHIC SETTING: Sweetwater soils are on nearly level flood plains and gently sloping subirrigated footslopes. Slope gradients are mostly less than 1 percent, but some are as much as 3 percent. The soil formed in sandy alluvium and colluvium in partly filled valleys. These valleys are usually adjacent to areas of upland sands. The mean annual precipitation from 18 to 25 inches, and the mean annual temperature ranges from 57 to 63 degrees F. Frost free days range from 180 to 210 days and eleevation ranges from 2,200 to 3,200 feet. The annual Thornthwaite P-E indices range from about 31 to 36.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the competing Lincoln series, and the Devol, Likes, Springer, and Tivoli series. Devol, Likes, Springer, and Tivoli soils lack a mollic epipedon and are well drained.
DRAINAGE AND PERMEABILITY: Poorly drained. Runoff is slow. Permeabiltiy is moderately slow. These soils are usually wet and are saturated at some period during the year. A water table is within 1/2 to 3 feet most of the year except during infrequent floods when it is ponded.
USE AND VEGETATION: Mainly used as native grass meadows or rangeland. Vegetation is bluestem, switchgrass, eastern gammagrass, indiangrass, tall dropseed, alkali sacaton, sedges, and widely spaced cottonwood trees, and clumps of willow and salt cedar in some places.
DISTRIBUTION AND EXTENT: Northern High Plains of Texas and western Oklahoma. The soil is inextensive.
MLRA OFFICE RESPONSIBLE: Temple, Texas
SERIES ESTABLISHED: Wheeler County, Texas; 1932.
REMARKS: Diagnostic horizons and features recognized in this pedon are:
Mollic epipedon - 0 to 14 inches (A1 horizon)
Aquic Feature - distinct mottles in the lower part of the mollic epipedon.
Fluvaquentic feature - organic carbon decreases irregularly with increasing depth.
Strongly contrasting particle size classes between the Az and C horizons at 24 inches.