Established Series


The Catilla series consists of very deep, moderately well drained, moderately slowly permeable soils on uplands. The soil formed from sandy and loamy deposits. Slope ranges from 0 to 5 percent.

TAXONOMIC CLASS: Loamy, siliceous, active, thermic Grossarenic Paleustalfs

TYPICAL PEDON: Catilla fine sand--rangeland. (Colors are for dry soil unless otherwise stated.)

A--0 to 10 inches; light brownish gray (10YR 6/2) fine sand, brown (10YR 4/3) moist; single grained; loose, very friable; common roots; slightly acid; clear smooth boundary. (3 to 16 inches thick)

E--10 to 46 inches; very pale brown (10YR 8/4) fine sand, very pale brown (10YR 7/4) moist; single grained; loose, very friable; few fine roots; few fine siliceous pebbles; moderately acid; clear wavy boundary. (24 to 54 inches thick)

Bt1--46 to 52 inches; light yellowish brown (10YR 6/4) sandy clay loam, yellowish brown (10YR 5/4) moist; weak coarse angular blocky structure; very hard, firm; few fine roots; many medium pores; few fine and medium distinct light gray (10YR 7/1) iron depletions; strongly acid; gradual smooth boundary. (4 to 12 inches thick)

Bt2--52 to 65 inches; light yellowish brown (10YR 6/4) sandy clay loam, yellowish brown (10YR 5/4) moist; weak coarse angular blocky structure; very hard, firm; few distinct clay films in pores; about 5 percent iron enriched dark red masses of iron accumulation; common coarse prominent dark red (10R 3/6) and few fine faint light gray (10YR 7/1) iron depletions; strongly acid. (6 to 20 inches thick)

Bt3--65 to 80 inches; light gray (10YR 7/1) sandy clay loam; weak coarse blocky structure; very hard, firm; about 10 percent iron enriched dark red masses of iron accumulation; many prominent coarse dark red (10R 3/6) and few fine and medium yellowish brown (10YR 5/4) masses of iron accumulation; strongly acid.

TYPE LOCATION: DeWitt County, Texas; about 4 miles north of Cuero, Texas to the junction of U.S. Highways 183 and 77A; then north on U.S. Highway 77A, 4.9 miles to the Edgar Community on U.S. Highway 77A; then 0.15 mile east; 0.95 mile south; and 0.55 mile east on a county road, and 310 feet south of road corner in a pasture.

RANGE IN CHARACTERISTICS: Solum thickness ranges from 60 to over 100 inches. Coarse fragments, that are mainly siliceous pebbles, may occur in any horizon of some pedons and range up to about 10 percent by volume.

The A and E horizons are fine sand, loamy sand or loamy fine sand and are slightly or medium acid. The A horizon has hue of 10YR, value of 4 to 7, and chroma of 2 to 4. The E horizon has hue of 7.5YR or 10YR, value of 5 to 8, and chroma of 2 to 4.

The Bt horizons have hue of 10YR, value of 5 to 7, and chroma of 1 to 6. They are mottled in shades of red, yellow, and gray. Redoximorphic features are few or common in the upper part and increase in abundance and size with increasing depth. Texture is sandy clay loam except the upper 6 to 10 inches is sandy clay in some pedons. Reaction is moderately acid to very strongly acid. The depth to the horizon containing soft rounded masses of iron enriched red plinthite is from 40 to 60 inches below the surface.

COMPETING SERIES: These are the Desan, Padina, Matilo, Navasan, Patilo, Plains, and Tadina series (all Texas soils). Similar soils are the Arenosa, Boy, Eufaula, Kuy, Landman, Silstid, and Silvern series. Desan soils have redder argillic horizons and do not have redoximorphic features due to wetness in the argillic horizon. Padina soils do not have large masses of iron enriched materials and have slightly cooler soil temperatures. Matilo soils have a paralithic contact with sandstone between 60 and 80 inches of the surface. Navasan soils have a water table in most years within 60 inches of the surface. Patilo soils are dry in the moisture control section for longer periods of time. Plains soils have mean annual soil temperature of 57 to 62 degrees F., and do not have plinthite in the solum. Tadina soils do not have plinthite in the argillic horizon. Arenosa soils do not have argillic horizons. Boy and Landman soils are moist for longer periods of time and have udic moisture regimes. Eufaula soils have argillic horizons that consist of lamella. Kuy soils have warmer soil temperatures and have a udic moisture regime. Silstid soils have sandy A horizons 20 to 40 inches thick. Silvern soils contain more than 35 percent coarse fragments in the control section.

GEOGRAPHIC SETTING: Catilla soils are on uplands. Slopes range from 0 to 5 percent, with convex and concave surfaces. The soil formed in thick sandy and loamy deposits mainly of Citronelle or Willis geology that have been reworked somewhat by wind. The range in mean annual temperature is 70 degrees to 72 degrees F., average annual precipitation is 32 to 43 inches, and Thornthwaite annual P-E index is 44 to 64.

GEOGRAPHICALLY ASSOCIATED SOILS: These are the competing Silvern series and the Newulm and Tremona series. Silvern soils are on similar positions. Newulm and Tremona soils are on slightly lower nearby positions, have thinner sandy A horizons, and have clayey control sections.

DRAINAGE AND PERMEABILITY: Moderately well drained. Permeability is moderately slow. Runoff is negligible on slopes less than 1 percent, very low on 1 to 3 percent slopes, and low on 3 to 5 percent slopes.

USE AND VEGETATION: Mainly brushy rangeland and used for grazing. A few areas are used for improved bermudagrass pastures. Native vegetation is post oak and blackjack oak with yaupon, grapevines, and annual weeds and grasses.

DISTRIBUTION AND EXTENT: Mainly in the southern part of the Texas Claypan area of south Texas. The soil is of moderate extent.


SERIES ESTABLISHED: DeWitt County, Texas; 1973.

REMARKS: The soils were formerly included in the Patilo series.

Diagnostic horizons and features recognized in this pedon are:

Ochric epipedon - 0 to 46 inches. (A and E horizons)

Grossarenic feature - Sandy epipedon more than 40 inches thick.

Argillic horizon - 46 to 75 inches. (Bt horizons)

National Cooperative Soil Survey