LOCATION EUFAULA OK+TXEstablished Series
TAXONOMIC CLASS: Siliceous, thermic Psammentic Paleustalfs
TYPICAL PEDON: Eufaula loamy fine sand--cultivated. (Colors are for dry soil unless otherwise stated.)
Ap--0 to 6 inches; pale brown (10YR 6/3) loamy fine sand, brown (10YR 5/3) moist; massive; slightly hard, very friable; slightly acid; clear smooth boundary. (3 to 12 inches thick)
E1--6 to 40 inches; pink (7.5YR 7/4) fine sand; light brown (7.5YR 6/4); moist; single grained; loose; slightly acid; clear wavy boundary. (24 to 60 inches thick)
E2 & Bt--40 to 80 inches; pink (7.5YR 7/4) fine sand, light brown (7.5YR 6/4) moist (E2); single grained; loose; with lamellae of yellowish red (5YR 5/6) loamy fine sand (Bt); the lamellae are massive; slightly hard, friable; wavy and discontinuous 1/8 inch to 1 inch thick and 2 to 4 inches apart; the lamellae have clay bridges between the sand grains; moderately acid.
TYPE LOCATION: Pontotoc County, Oklahoma; about 9 miles north of Ada; 1,280 feet west and 2,290 feet south of the northeast corner of sec. 9, T. 5 N., R. 6 E.
RANGE IN CHARACTERISTICS: Thickness of solum is 72 inches or more. The A1 or Ap horizon has hue of 7.5YR or 10YR, value of 4 to 7, and chroma of 2 to 4. It is fine sand or loamy fine sand and is massive or has weak granular structure. This horizon is loose or slightly hard and ranges from strongly acid to neutral.
The E1 horizon has hue of 5YR to 10YR, value of 5 to 8, and chroma of 2 to 4. It is fine sand or loamy fine sand. The reaction ranges from strongly acid to neutral.
The E2 horizon has hue of 5YR to 10YR, value of 5 to 8, and chroma of 2 to 4. It is fine sand or loamy fine sand. The reaction ranges from strongly acid to neutral.
The Bt horizon has hue of 2.5YR to 7.5YR, value of 4 to 6, and chroma of 4 to 8. It is fine sandy loam or loamy fine sand but the control section averages loamy fine sand. The Bt horizons that are continuous horizontally and vertically are less common than the Bt horizons of lamellae. Where present, the upper part of the continuous Bt horizon is loamy fine sand. This horizon is dominantly massive, but some pedons have weak subangular blocky structure in the thicker lamellae or in the continuous Bt horizons. The Bt horizon ranges from strongly acid to neutral.
COMPETING SERIES: These are the Aquilla series in the same family. Aquilla soils have a perched water table.
GEOGRAPHIC SETTING: Eufaula soils are on nearly level to undulating, hummocky, or duney terraces on uplands in the Cross Timbers. Slopes range from 0 to 25 percent. The soils formed in sandy sediments of Pleistocene age. Mean annual precipitation range from 28 to 40 inches. Mean annual temperature ranges from 57 to 65 degrees F. Thornthwaite annual P-E indices ranges from 44 to 64.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the Dougherty, Stidham, and Carwile, Galey, Konawa, Noble, and Stephenville series. Carwile soils are on concave areas and have a fine control section. Dougherty and Konawa soils are on the lower half of side slopes and on foot slopes that are lower. In addition, Konawa soils have a loamy control section and thinner A horizons. Noble soils are on foot slopes that are lower and they lack argillic horizons. Stephenville soils are on the upper half of side slopes and crests and have sola 20 to 40 inches thick over sandstone bedrock. Stidham and Galey soils are on higher terraces and have a loamy control section.
DRAINAGE AND PERMEABILITY: Eufaula soils are somewhat excessively drained. Runoff ranges from negligible to medium and permeability is rapid.
USE AND VEGETATION: Dominantly used for range. Considerable amounts of the loamy fine sand on lesser slopes are cropped to sorghums, small grains, and peanuts; or used for tame pastures. Native vegetation is post oak and blackjack oak with an understory of tall grasses.
DISTRIBUTION AND EXTENT: Cross Timbers of central Oklahoma, central Texas, and south central Kansas. The series is extensive.
MLRA OFFICE RESPONSIBLE: Temple, Texas
SERIES ESTABLISHED: McIntosh County, Oklahoma; 1944.
REMARKS: Soil Interpretation Record No. OK0048
Diagnostic horizons and features recognized in this pedon are:
Ochric epipedon - the zone from the soil surface to a depth of 6 inches
Albic horizon - the zone from 6 to 40 inches (E horizon)
Argillic horizon - the zone of lamellae layers from 40 inches to 80 inches (Bt horizon)