LOCATION LAMPASAS TXEstablished Series
TAXONOMIC CLASS: Fragmental, mixed, thermic Udic Haplustolls
TYPICAL PEDON: Lampasas gravelly clay--rangeland. (Colors are for dry soil unless otherwise stated.)
A1--0 to 5 inches; dark reddish brown (5YR 3/2) gravelly clay, dark reddish brown (5YR 2/2) moist; moderate fine subangular blocky structure; hard, firm; many fine roots; common fine pores; 20 percent by volume of limestone fragments less than 3 inches across; mildly- alkaline; clear smooth boundary. (4 to 9 inches thick)
A2--5 to 13 inches; dark reddish brown (5YR 3/2) very gravelly clay, dark reddish brown (5YR 2/2) moist; moderate very fine subangular blocky structure; hard, firm; common fine and medium roots; common fine pores; 60 percent by volume of limestone fragments less than 3 inches across and 10 percent by volume of limestone fragments from 3 to 5 inches across; mildly alkaline; abrupt wavy boundary. (5 to 11 inches thick)
C--13 to 60 inches; bed of interlocking very pale brown fragmental limestone; fractured at about 1 to 4 inch intervals with thin coatings of secondary carbonates along some fractures; few roots only along fractures.
TYPE LOCATION: Lampasas County, Texas; from the intersection of U.S. Highway 183 and Farm Road 2942 in Lometa, 4.9 miles north on Farm Road 2942, 30 feet east in rangeland.
RANGE IN CHARACTERISTICS: Solum thickness ranges from 9 to 20 inches. The fine-earth fraction is clay loam, silty clay loam, or clay with a clay content of 35 to 45 percent. Reaction is neutral to mildly alkaline in the fine-earth fraction and is calcareous in some pedons.
The A horizon has hue of 5YR, 7.5YR, or 10YR, values of 2 to 4, and chroma of 2 or 3. Coarse fragments comprise 35 to 80 percent of the solum and consist of limestone fragments mainly less than 3 inches across. Some pedons contain from 5 to 15 percent limestone fragments from 3 to 10 inches across. Individual horizons are gravelly, very gravelly or extremely gravelly counterparts of the fine-earth fraction and the amount of fragments increases with depth.
The C horizon is a bed of interlocking fragmental limestone or claystone with fractures at various angles. Size of fragments is typically 2 to 4 inches but ranges from 1/2 inch to 6 inches across.
COMPETING SERIES: There are no other series in this family. Similar soils are the Cho, Mereta, Eckrant and Oglesby series. None of these soils are in a fragmental family. Cho, Mereta, and Oglesby soils have less than 35 percent coarse fragments in the control section. In addition, Cho and Mereta soils have petrocalcic horizons.
GEOGRAPHIC SETTING: Lampasas soils are on gently sloping uplands. Surfaces are typically convex with slopes from 1 to 5 percent. These soils formed in fragmental limestone (claystone) of the Walnut Formation of the Lower Cretaceous Period. Mean annual precipitation is 26 to 34 inches. Mean annual temperature is 64 to 68 degrees F. Frost free days range from 220 to 240 and elevation ranges from 1000 to 1700 feet above sea level. Thornthwaite P-E indices range from 44 to 56.
GEOGRAPHICALLY ASSOCIATED SOILS: These include the Brackett, Cho, Doss, Krum and Nuff soils. Brackett, Cho and Doss soils are typically at higher elevations. Brackett, Cho and Doss soils contain less than 35 percent coarse fragments. Krum soils are in lower valley positions. Nuff soils occur on similar surfaces.
DRAINAGE AND PERMEABILITY: Well drained; Runoff is very low on slopes of 1 to 3 percent, and low on slopes of 3 to 5 percent. Permeability is moderately slow.
USE AND VEGETATION: Used mainly as rangeland. Vegetation is predominantly mid and short grasses, with an overstory of live oak and some juniper, elm, and hackberry trees.
DISTRIBUTION AND EXTENT: Grand Prairie Land Resource Area in Central Texas. The series is of moderate extent.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Temple, Texas
SERIES ESTABLISHED: Lampasas County, Texas 1989.
REMARKS: The fragmental limestone or claystone is finely fractured. Fractures transmit water to lower depths but restrict roots. It is readily excavated by heavy equipment and used for road and construction fill material.
At the present time there is not a clayey-skeletal over fragmental particle-size class in the classification system. If there were, this soil would be in that particle-size class with montmorillonitic mineralogy.
Diagnostic horizons and features recognized in this pedon are:
Mollic epipedon - 0 to 13 inches.