LOCATION NAVASAN TXEstablished Series
TAXONOMIC CLASS: Loamy, siliceous, active, thermic Grossarenic Paleustalfs
TYPICAL PEDON: Navasan loamy fine sand - pasture. (Colors are for dry soil unless otherwise stated.)
A--0 to 4 inches; brown (10YR 5/3) loamy fine sand, dark brown (10YR 4/3) moist; weak fine and medium subangular blocky structure; loose, very friable; common fine and medium roots; strongly acid; clear smooth boundary. (3 to 15 inches thick)
E1--4 to 15 inches; very pale brown (10YR 7/3) loamy fine sand, pale brown (10YR 6/3) moist; few fine distinct yellowish brown (10YR 5/6) mottles; weak medium subangular blocky structure; soft, very friable; common fine and medium roots; strongly acid; clear wavy boundary.
E2--15 to 31 inches; very pale brown (10YR 7/3) loamy fine sand, pale brown (10YR 6/3) moist; few medium distinct yellowish brown (10YR 5/8) mottles; some mottles have strong brown (7.5YR 5/6) centers; weak medium subangular blocky structure; soft, very friable; few fine and medium roots; moderately acid; clear wavy boundary.
E3--31 to 51 inches; very pale brown (10YR 8/3) loamy fine sand, very pale brown (10YR 7/3) moist; common medium distinct yellowish brown (10YR 5/6) mottles with strong brown (7.5YR 5/6) centers; weak medium subangular blocky structure; soft, very friable; few fine and medium roots; moderately acid; clear smooth boundary. (combined thickness of E horizons is 25 to 58 inches.)
B/E--51 to 61 inches; brownish yellow (10YR 6/6) fine sandy loam (B), yellowish brown (10YR 5/6) moist; moderate fine subangular blocky structure, slightly hard, friable; some spots are slightly brittle when moist; about 30 percent streaks and pockets of very pale brown (10YR 7/3)loamy fine sand (E); pockets are 2 to 4 inches in diameter and at intervals of 8 to 12 inches; few 1/4 to 1/2 inch diameter iron-manganese concretions and nodules; strongly acid; abrupt smooth boundary. (7 to 15 inches thick)
Bt--61 to 66 inches; brown (10YR 5/3) fine sandy loam, dark brown (10YR 4/3) moist; few fine distinct yellowish brown (10YR 5/6) mottles with strong brown centers; weak coarse angular blocky structure; slightly hard, friable; few thin patchy clay films on surfaces of peds; strongly acid; clear smooth boundary. (0 to 12 inches thick)
Btg1--66 to 74 inches; light gray (10YR 7/2) sandy clay loam, light brownish gray (10YR 6/2) moist; common medium prominent strong brown (7.5YR 5/6) and few fine prominent brownish yellow (10YR 6/6) mottles; weak coarse angular blocky structure; hard, firm; few thin patchy clay films on surfaces of peds; few small masses of clean sand; strongly acid; clear wavy boundary. (6 to 18 inches thick)
Btg2--74 to 90 inches; light gray (10YR 7/1) sandy clay loam, gray 10YR 6/1) moist; few fine prominent strong brown (7.5YR 5/6) and brownish yellow (10YR 6/6) mottles; weak coarse angular blocky structure; hard, firm; common continuous clay films on surfaces of peds; strongly acid; clear smooth boundary.
TYPE LOCATION: Brazos County, Texas; from intersection of Highway 21 and Democrat Road near Kurten, 2.6 miles northeast on Democrat Road to intersection of Democrat and Plagens Roads, 0.3 mile northeast on Democrat Road, 1.75 miles east on semiprivate road to cabin, 2,500 feet east along powerline, site is 200 feet north in pasture.
RANGE IN CHARACTERISTICS: Solum thickness is more than 80 inches. A perched water table is at a depth of about 60 inches throughtout most of the year. Combined thickness of the A and E horizons ranges from 40 to 60 inches. Siliceous and ironstone pebbles mainly less than 1/2 inch in diameter typically range from none to few. Some subhorizons have thin discontinuous strata or clusters of pebbles.
The A or Ap horizon has hue of 7.5YR or 10YR, value of 4 to 6, and chroma of 3 or 4. A few brownish mottles are in some pedons. Texture is loamy sand or loamy fine sand. Reaction ranges from strongly acid to neutral.
The E horizon has hue of 7.5YR or 10YR, value of 6 to 8, and chroma of 3 or 4. Most pedons contain few to common brownish or yellowish mottles in the lower part. Reaction ranges from strongly acid to neutral. Texture is loamy sand or loamy fine sand.
The B/E or E/B horizon consists of loamy subsoil with streaks and spots of sandy E soil material or sandy E material with spots of loamy B soil material. The B material has hue of 7.5YR or 10YR, value of 4 to 6, and chroma of 4 to 8. Texture is fine sandy loam, sandy clay loam or loam. The E portion has hue of 10YR, value of 6 or 7, and chroma of 1 to 3. The texture is loamy sand or loamy fine sand. Reaction ranges from very strongly acid to medium acid.
The Bt horizon has hue of 7.5YR or 10YR, value of 4 to 6, and chroma of 3 to 6. Mottles in shades of brown, yellow or gray range from few to common. Texture is sandy loam or fine sandy loam.
The Btg horizons have grayish matrix colors with few to many mottles. High chroma colors are in hue of 2.5YR to 10YR, value of 3 to 5, and chroma of 4 to 8. Low chroma colors are in hue of 10YR, value of 4 to 7, and chroma of 1 or 2. Some pedons have a mottled matrix of these colors. Texture is sandy clay loam or clay loam. The reaction is strongly acid or medium acid.
Some pedons have a loamy BC horizon below a depth of 60 inches. These horizons are in shades of brown or yellow with or without brownish or grayish mottles. The reaction ranges from strongly acid to slightly acid.
COMPETING SERIES: These soils include Catilla, Desan, Matilo, Padina and Patilo of the same family. Catilla soils are on uplands and do not have a water table within 60 inches of the surface. Desan soils do not have wetness mottles in the Bt horizon. Matilo, Padina and Patilo soils do not have a water table within 60 inches of the surface. In addition Matilo soils have a paralithic contact of sandstone at a depth of 60 to 80 inches.
GEOGRAPHIC SETTING: Navasan soils are on first level terraces within or adjacent to flood plains. They are about 3 to 10 feet above the flood plain. The soil formed in sandy alluvium of late Pleistocene or Recent Age. Slopes range from 0 to 5 percent, with plane or convex surfaces. The mean annual temperature ranges from 66 to 68 degrees F, and average annual precipitation ranges from 34 to 40 inches. Frost free days range from 270 to 280, and the elevation ranges from 205 to 250 feet above sea level. The Thornthwaite P-E indices range from 54 to 64.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the competing Desan and Padina series, and the Dutek, Gladewater, Kaufman, Robco and Sandow series. Desan and Padina soils are above on higher terrace or upland positions. The Dutek and Robco soils have surface layers less than 40 inches thick and are on higher terrace or upland positions. The Gladewater and Kaufman soils are clayey throughout, and the Sandow soils are loamy throughout. These soils are on adjacent flood plains.
DRAINAGE AND PERMEABILITY: Moderately well drained; slow runoff. This soil has rapid permeability in the upper part and moderately slow permeability in the lower part of the solum. A water table is present at a depth of 4 to 6 feet for a cumulative annual duration of 1 to 4 months during most of the year. Flooding ranges from none to rare for brief to very long periods.
USE AND VEGETATION: Used mainly for improved pasture and for rangeland. Native vegetation is a post oak and yaupon savannah with an understory of tall and midgrasses. Overgrazing causes brush species to invade and increase changing the savannah to thick brush with little understory in some areas. Pastures consist mainly of improved bermudagrass.
DISTRIBUTION AND EXTENT: Typically on first level terraces of the Navasota River and adjacent local streams. The soil is of minor extent.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Temple, Texas
SERIES ESTABLISHED: Grimes County, Texas, 1988. Series was proposed in adjoining Brazos County.
REMARKS: These soils were formerly included with the sandy flood plains.
Diagnostic horizons and features recognized in this pedon are:
Ochric epipedon - 0 to 51 inches
Albic horizon - 4 to 51 inches (not required for series)
Grossarenic feature - 0 to 51 inches of loamy fine sand
Argillic horizon - 61 to 90 inches
Glossic horizon - 51 to 61 inches (not required).