LOCATION NIMROD TXEstablished Series
TAXONOMIC CLASS: Loamy, siliceous, active, thermic Aquic Arenic Paleustalfs
TYPICAL PEDON: Nimrod fine sand--scrub oak wooded pasture.
(Colors are for dry soil unless otherwise stated.)
A--0 to 4 inches; grayish brown (10YR 5/2) fine sand, dark grayish brown (10YR 4/2) moist; single grained; loose; neutral; abrupt irregular boundary. (0 to 12 inches thick)
E--4 to 27 inches; very pale brown (10YR 7/3) fine sand, pale brown (10YR 6/3) moist; single grained; loose; slightly acid; abrupt wavy boundary. (8 to 30 inches thick)
Bt1--27 to 40 inches; coarsely mottled light gray (10YR 7/2), reddish yellow (7.5YR 6/6), and yellowish brown (10YR 5/6) sandy clay loam; strong prismatic structure parting to coarse blocky; extremely hard, very firm; peds are coated with gray (10YR 5/1) fine sand; distinct clay films on vertical surfaces of peds; strongly acid; gradual wavy boundary. (0 to 24 inches thick)
Bt2--40 to 53 inches; light gray (10YR 7/2) sandy clay loam, light brownish gray (10YR 6/2) moist; common coarse mottles of olive brown (2.5Y 4/4) and red (2.5YR 4/6); strong coarse prismatic structure parting to weak blocky; extremely hard, very firm; distinct clay films and sandy coatings of gray (10YR 5/1) on vertical faces of prisms; few ferromanganese oxide concretions 2 to 5 mm in diameter; few sandstone fragments; strongly acid; gradual wavy boundary. (4 to 20 inches thick)
Bt3--53 to 68 inches; light gray (10YR 7/2) sandy clay loam, light grayish brown (10YR 6/2) moist; common coarse red and brownish mottles; strong coarse prismatic structure; extremely hard, very firm; surfaces of peds coated with clean gray sand; few ferromanganese oxide concretions; few ferruginous sandstone fragments; medium acid; diffuse wavy boundary. (8 to 24 inches thick)
BC--68 to 80 inches; coarsely mottled, red (2.5YR 5/6) dry and moist, and light gray (10YR 7/2) sandy loam predominantly red in the upper part and mostly gray in the lower part; weak prismatic structure in the upper part and massive below; very hard, very firm; roots penetrate to 80 inches; slightly acid.
TYPE LOCATION: Erath County, Texas; from the Erath County Courthouse in Stephenville, Texas; north 1.4 miles on Texas Highway 108 to the junction of Texas Highway 108 and Farm Road 2303; 3.5 miles west on Farm Road 2303; south 50 yards on private road and 75 yards east in a wooded area.
RANGE IN CHARACTERISTICS: Thickness of the solum ranges from 60 to more than 80 inches. A few sandstone fragments usually less than 3 inches across the long axis are on the surface and throughout the solum in some pedons.
The A horizon is 20 to 40 inches thick. Colors are in hue of 7.5YR or 10YR, value of 4 to 7, and chroma of 2 to 4. The E horizon is typically 1 to 3 units of value greater than the A horizon. Texture is fine sand or loamy fine sand. Reaction ranges from medium acid to neutral.
The Bt and BC horizons are mottled and have brownish, grayish, and yellowish colors with or without reddish mottles. Dominant colors are in hue of 7.5YR or 10YR, value of 5 to 7, and chroma of 2 to 6. Texture is mainly sandy clay loam with clay content of 20 to 35 percent. Reaction is strongly acid or medium acid.
The C horizon, when present, is mottled in shades of gray, red, yellow, or brown sandy clay loam, sandy loam, or loamy fine sand, or the horizon is weakly cemented sandstone. Reaction ranges from strongly acid through slightly acid.
COMPETING SERIES: These are the Coving and Robco series in the same family and the Demona, Nueces, Patilo, and Selden series. Reaction of Coving soils range from medium acid through mildly alkaline in the argillic horizon. Robco soils have Bt/E horizons, receive more effective precipitation, are in a typic-udic moisture area and are slowly permeable. Demona soils have clayey control sections. Nueces soils have mixed mineralogy and hyperthermic temperature regime. Patilo soils have sandy epipedons 40 to 80 inches thick. Selden soils have epipedons less than 20 inches thick.
GEOGRAPHIC SETTING: Nimrod soils occur on undulating uplands. Slope gradients range from 0 to 8 percent. The soils formed in sands, sandy loams, and sandy clay loams, in places reworked by winds. Mean annual precipitation ranges from 24 to 36 inches and mean annual temperature ranges from 63 to 68 degrees F. Frost free days range from 210 to 240 days and elevation ranges from 700 to 1500 feet. Annual Thornthwaite P-E indices range from 36 to 64.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the competing Demona, Patilo, and Selden series and the Duffau and Windthorst series. Demona and Duffau soils are below in concave positions. In addition, Duffau soils have an epipedon less than 20 inches thick and lack mottles with chroma of 2 or less. Patilo and Selden soils are on similar positions. Windthorst soils have clayey, argillic horizons and are above on low ridges or convex stream divides.
DRAINAGE AND PERMEABILITY: Moderately well drained. Permeability is moderately slow. The surface horizon rapidly absorbs rainfall. For short periods following heavy rainfall, a perched water table is at the top of the B horizon.
USE AND VEGETATION: In the past most of these soils were cleared and cultivated. Many have reverted to forest of post oak and blackjack oak. Cultivated areas are now used mainly for growing peanuts. Original vegetation was scrub forest of post oak and blackjack oak, and a heavy understory of greenbriers, little bluestem, and purpletop grasses.
DISTRIBUTION AND EXTENT: North Central Prairie, Rolling Limestone Prairie, Grand Prairie and West Cross Timbers of Texas. The soil is of large extent.
MLRA OFFICE RESPONSIBLE: Temple, Texas
SERIES ESTABLISHED: Eastland County, Texas; 1917.
REMARKS: Diagnostic horizons and features recognized in this pedon are:
Ochric epipedon - from the surface to a depth of 27 inches - the A and E horizons.
Arenic feature - fine sand texture to 27 inches - (A and E horizons)
Argillic horizon - from a depth of 27 to 68 inches. (Bt horizons)
Pale feature - the horizon does not have a clay decrease of 20 percent or more from the maximum within 60 inches of the surface.
Aquic feature - has gray mottles in the Bt horizon within 30 inches of the soil surface.