LOCATION AVILLA AREstablished Series
TAXONOMIC CLASS: Fine-loamy, siliceous, semiactive, thermic Typic Paleudults
TYPICAL PEDON: Avilla silt loam on a smooth 4 percent slope, in pasture. (Colors are for moist soil unless otherwise stated.)
Ap1--0 to 3 inches; brown (10YR 4/3) silt loam; weak fine and medium granular structure; friable; many fine roots; about 1 percent by volume rounded sandstone gravel less than 3 inches in diameter; slightly acid; clear smooth boundary. (2 to 7 inches thick)
Ap2--3 to 9 inches; dark yellowish brown (10YR 4/4) silt loam; moderate fine and medium granular structure; friable; common fine roots; about 1 percent by volume rounded sandstone gravel less than 3 inches in diameter; moderately acid; clear smooth boundary. (0 to 7 inches thick)
Bt1--9 to 19 inches; yellowish red (5YR 5/8) clay loam; weak medium subangular blocky structure; friable; few fine roots; common fine pores; about 5 percent by volume rounded sandstone gravel less than 3 inches in diameter; thin faint (patchy) clay films on faces of some peds; strongly acid; clear wavy boundary.
Bt2--19 to 31 inches; red (2.5YR 5/8) clay loam; moderate medium subangular blocky structure; firm; many fine pores; few fine roots; about 7 percent by volume rounded sandstone gravel less than 3 inches in diameter; thin faint (patchy) clay films on faces of most peds; very strongly acid; clear wavy boundary.
Bt3--31 to 56 inches; mottled, red (2.5YR 4/8), strong brown (7.5YR 5/8), and brownish yellow (10YR 6/6) clay loam; moderate medium subangular blocky structure; friable; few fine pores; about 12 percent by volume rounded sandstone gravel less than 3 inches in diameter; thin faint (patchy) clay films on on faces of most peds; very strongly acid; gradual wavy boundary.
Bt4--56 to 72 inches; mottled, red (2.5YR 4/8), yellowish red (5YR 5/8), strong brown (7.5YR 5/8), and light gray (10YR 7/2), very gravelly clay loam; moderate medium and coarse subangular blocky structure; friable; few fine pores; about 60 percent by volume rounded sandstone gravel less than 3 inches in diameter; thin faint (patchy) clay films on faces of most peds and on gravel; very strongly acid. (Combined thickness of the Bt horizons ranges from 46 to more than 83 inches.)
TYPE LOCATION: Saline County, Arkansas; 1 mile north of Paron on Highway 9, then east about 50 feet on a terrace of the Saline River in the NW1/4SE1/4SE1/4, sec. 25, T. 2 N., R. 17 W.
RANGE IN CHARACTERISTICS: Solum thickness ranges from 60 to more than 85 inches. Reaction is strongly or very strongly acid throughout except for surface layers that have been limed. Sandstone and shale fragments less than 3 inches in diameter range from 0 to 25 percent by volume in the A horizon; 0 to 15 percent by volume in the E, BE and BA horizons, where present; 0 to 15 percent by volume in the Bt1 and Bt2 horizons; 0 to 35 percent by volume in the Bt3 horizon and 15 to 60 percent by volume in the Bt4 and BC horizons.
The A horizon has hue of 10YR, value of 4 or 5, and chroma of 2 through 4,or hue of 7.5YR, value of 4, and chroma of 4.. Some pedons have an A1 horizon, 2 to 4 inches thick, that has hue of 10YR, value 3, and chroma 1, 2 or 3. Textures are silt loam, loam, fine sandy loam, gravelly fine sandy loam, gravelly loam or gravelly silt loam.
The E horizon, where present, has hue of 10YR, value of 5 or 6, and chroma of 3 or 4. Texture is fine sandy loam, very fine sandy loam, loam, silt loam.
The BA or BE horizons, where present, has hue of 5YR, value of 4 or 5, and chroma of 4, 6 or 8, or hue of 7.5YR, value of 4, and chroma of 4, or value of 5, and chroma of 4, 6 or 8. Texture is fine sandy loam, loam, silt loam, clay loam or sandy clay loam.
The Bt1 horizon has hue of 7.5YR, value of 4, and chroma of 4, or value of 5, and chroma of 6 or 8, or hue of 5YR, value of 4 or 5, and chroma of 4, 6 or 8. Mottles range from none to common in shades of brown. Texture is loam, sandy clay loam or clay loam.
The Bt2 horizon has hues of 2.5YR or 5YR, value of 4 or 5, and chroma of 4, 6, or 8, or 7.5YR, value of 5, and chroma of 6 or 8. Mottles range from none to common in shades of yellow, brown or red. Gray mottles may occur below 30 inches from the surface. Texture is clay loam, sandy clay loam or loam.
The Bt3 horizon has hues of 2.5YR or 5YR, value of 4 or 5, and chroma of 4, 6 or 8. Mottles are in shades of brown, yellow, red and gray. Many pedons lack a dominant matrix color and are mottled in shades of yellow, red, brown and gray. Gray mottles occur below 30 inches from the surface. Textures are sandy clay loam, clay loam, loam, gravelly sandy clay loam, gravelly clay loam or gravelly loam.
The Bt4 horizon has hues of 5YR or 2.5YR, value of 4 or 5, and chroma of 4, 6 or 8 and mottles in shades of red, brown, yellow and gray or it is a mottled horizon in these colors. Texture is gravelly loam, gravelly clay loam, gravelly sandy clay loam, very gravelly clay loam, very gravelly sandy clay loam, or very gravelly loam.
The BC horizon, where present, has hues of 2.5YR or 5YR, value of 4 or 5, chroma or 4, 6 or 8. Mottles are in shades of red, brown, yellow or gray. This horizon usually lacks a dominant matrix color and is mottled in shades of red, brown, yellow and gray. Texture is gravelly clay loam, gravelly sandy clay loam, gravelly loam, very gravelly clay loam, very gravelly sandy clay loam or very gravelly loam.
COMPETING SERIES: These are the Allen, Dubach, Etowah, Holston, Nella, Octavia, Ruston, Sailes, Silsbee, and Warnock. Allen and Etowah soils contain less than 15 percent coarse fragments in the lower Bt horizons. Dubach soils are on stream terraces in the Western Coastal Plain and have an apparent water table at 3.5 to 5 feet. Holston soils have Bt horizons dominated by hues of 7.5YR or 10YR. Nella soils have base saturations of less than 20 percent. Octavia soils contain a lithologic discontinuity and a perched water table at 3.5 to 5 feet. Ruston soils are bisequal. Sailes soils formed in loamy marine sediments on the Western Coastal Plain. Silsbee soils formed in loamy sediments on the Western Gulf Coast Flatwoods. Warnock soils have Bt horizons dominated by hues of 7.5YR or 10YR, exhibit some brittleness, and contain plinthite.
GEOGRAPHIC SETTING: Avilla soils are on nearly level to moderately sloping terraces in and adjacent to the Ouachita Mountains in Arkansas and Oklahoma.
They formed in loamy alluvium weathered from acid, interbedded sandstone and shale formations. Slopes range from 1 to 12 percent. Average annual precipitation
ranges from about 46 to 56 inches. Mean annual temperature ranges from 59 degrees to 65 degrees F.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the
Carnasaw,
Ceda,
Kenn,
Leadvale
Sherless and
Speer series. Carnasaw soils, which are adjacent upland, have clayey control sections, 40 to 60 inches sola over soft bedrock.
Ceda soils, which are on floodplains, have loamy-skeletal control sections and no argillic horizon. Kenn soils, which are on floodplains and low terraces, have 40 to
60 inch sola and higher base saturation. Leadvale soils, which are in adjacent valleys, have fine-silty control sections and fragipans. Sherless soils, which are on
adjacent uplands, have 20 to 40 inch sola over soft bedrock. Speer soils, which are on adjacent floodplains and low terraces, have 40 to 60 inch sola and higher
base saturation.
DRAINAGE AND PERMEABILITY: Avilla soils are well drained; runoff is slow to rapid; permeability is moderate.
USE AND VEGETATION: The dominant use is for pasture and hay crops. Some areas are in mixed hardwood and pine forests. Minor areas are in cultivated
crops such as soybeans, grain sorghum or wheat. The native vegetation was mainly mixed hardwoods and pine with an understory of grasses. The hardwoods were
mainly oaks, walnuts, and sweetgums. The pines were mainly shortleaf pine.
DISTRIBUTION AND EXTENT: Ouachita Mountains of Arkansas and Oklahoma. The series is of moderate extent.
MLRA OFFICE RESPONSIBLE: Little Rock, Arkansas
SERIES ESTABLISHED: Saline County, Arkansas; 1976.
REMARKS: Diagnostic horizons recognized in this pedon are:
ochric epipedon - 0 to 9 inches
argillic horizon - 9 to 72 inches
These soils were formally mapped in the Sallisaw series.