LOCATION DARCO TX+AR MSEstablished Series
TAXONOMIC CLASS: Loamy, siliceous, semiactive, thermic Grossarenic Paleudults
TYPICAL PEDON: Darco loamy fine sand--woodland. (Colors are for moist soil unless otherwise stated.)
Ap--0 to 10 inches; brown (10YR 4/3) loamy fine sand; single grained; loose; common fine roots; slightly acid; gradual smooth boundary. (3 to 15 inches thick)
E1--10 to 18 inches; brown (10YR 5/3) loamy fine sand; single grained; loose; common fine roots; slightly acid; gradual smooth boundary. (0 to 12 inches thick)
E2--18 to 30 inches; yellowish brown (10YR 5/4) loamy fine sand; common fine faint brown (10YR 5/3) mottles; single grained; loose; few fine roots, slightly acid; gradual smooth boundary. (8 to 20 inches thick)
E3--30 to 46 inches; brown (7.5YR 5/4) loamy fine sand; common fine faint light yellowish brown mottles; single grained; loose; common fine roots; slightly acid; clear smooth boundary. (15 to 30 inches thick)
Bt1--46 to 62 inches; dark red (2.5YR 3/6) sandy clay loam; moderate fine subangular blocky structure; hard, friable; few fine pores; few fine roots between peds; thick patchy reddish brown (5YR 5/4) clay films mainly on horizontal faces of peds; few horizontal streaks of brown (7.5YR 5/4) in lower part; very strongly acid; diffuse smooth boundary. (10 to 20 inches thick)
Bt2--62 to 74 inches; red (2.5YR 4/6) sandy clay loam; many coarse faint red (2.5YR 5/8) mottles; weak medium subangular blocky structure; hard, very friable; few fine roots and pores; thin patchy clay films on vertical surfaces of peds; very strongly acid; diffuse smooth boundary. (10 to 18 inches thick)
Bt3--74 to 86 inches; red (2.5YR 4/6) sandy clay loam; common coarse faint red (2.5YR 5/8) mottles weak medium subangular blocky structure; hard, very friable; few fine roots and pores; thin patchy clay films on vertical surfaces of peds; very strongly acid.
TYPE LOCATION: Anderson County, Texas; about 6.5 miles southeast of Elkhart. From the intersection of U. S. Highway 287 and Texas Highway 294, 4.4 miles southeast to Salmon Missionary Baptist Church, 0.4 mile east on county road. Site is 50 feet north of road.
RANGE IN CHARACTERISTICS:
Solum thickness: More than 80 inches
Clay content in the Control Section: 12 to 35 percent
Redoximorphic features: Iron concentrations in shades of brown, yellow, or red and iron depletions with chroma of 2 or less are in the subsoil below a depth of 50 inches in some pedons
Other distinctive soil features: The sand fraction contains less than 10 percent coarse or very coarse sand. Thickness of the sandy epipedon ranges from 40 to 72 inches
Concentrated minerals: Base saturation ranges from 15 to 35 percent in the lower part of the Bt horizon. The exchangeable calcium content ranges from 1 to 3 meq./100 grams of soil.
A horizon:
Color--Hue of 10YR, value of 3 to 5, and chroma of 2 or 3
Redoximorphic features--None
Texture--Loamy fine sand or fine sand
Other features--None
Reaction--Very strongly acid to slightly acid unless limed
E horizon:
Color--Hue of 7.5YR or 10YR, value of 4 to 6, and chroma of 3 or 4
Redoximorphic features--None
Texture--Loamy fine sand or fine sand
Other features--None
Reaction--Very strongly acid to slightly acid
BE horizon: (where present)
Color--Hue of 7.5YR or 10YR, value of 4 to 6, and chroma of 6 or 8
Redoximorphic features--None
Texture--Loamy fine sand or fine sand
Other features--None
Reaction--Very strongly acid to slightly acid
Bt horizon:
Color--Hue of 2.5YR to 10YR, value of 4 to 6, and chroma of 6 to 8
Redoximorphic features--Iron concentrations in shades of brown, yellow, or red range from none to common. Iron depletions with chroma of 2 or less are below a depth of 50 inches in some pedons.
Texture--Fine sandy loam or sandy clay loam, however clay loam textures also are below a depth of 60 inches in some pedons
Other features--Plinthite segregations range from 0 to 5 percent
Reaction--Very strongly acid to strongly acid
COMPETING SERIES: These are the Blanton, Eddings, Murad, Shankler, and Tehran series in the same family and the Albany, Alaga, Betis, Briley, Gunter, Kenney, Lilbert, Pickton, Tonkawa, and Troup series in closely related families. Albany, Blanton, Eddings, and Murad soils contain redox depletions in the upper part of the Bt horizon and are seasonally saturated in the lower part of the epipedon. Shankler soils have a summer moisture deficit of 0 to 4 inches, receive more than 30 inches of frost-free rainfall, and formed in parent materials from the Willis formation. Tehran soils contain more than 10 percent coarse or very coarse sands. Troup soils have a kandic horizon. Alaga and Tonkawa soils are sandy throughout and do not have an argillic horizon. Betis soils have an argillic horizon that consists of lamellae. Briley and Lilbert soils have a sandy epipedon that is 20 to 40 inches thick. Gunter soils contain more than 5 percent plinthite in the Bt horizon. Kenney and Pickton soils are Alfisols.
GEOGRAPHIC SETTING: Darco soils are on gently sloping to steep uplands. Slope gradients are dominantly 2 to 10 percent but range from 1 to 25 percent. They formed in sandy and loamy Southern Coastal Plain deposits. The climate is warm and humid. The average annual rainfall ranges from 40 to 50 inches. Frost free days range from 230 to 260. Elevation ranges from 400 to 700 feet. The frost-free rainfall ranges from 25 to 30 inches. Summer moisture deficit ranges from 4 to 6 inches. The mean annual temperature ranges from 63 to 68 degrees F. and the P-E index ranges from 64 to 84.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the closely related Betis, Briley, Lilbert, and Tonkawa soils, and the Cuthbert and Tenaha series. Betis, Briley, and Lilbert soils are on positions similar to Darco. Tonkawa soils are on similar or slightly higher positions in the landscape. Cuthbert soils have a loamy epipedon and the Tenaha soils have a sandy epipedon that is 20 to 40 inches thick. These soils are on lower sideslope positions.
DRAINAGE AND PERMEABILITY: Darco soils are somewhat excessively drained. Permeability is rapid in the sandy epipedon, and moderate in the argillic horizon. Runoff is negligible on 1 to 5 percent slopes, very low on 5 to 20 percent slopes, and low on slopes greater than 20 percent.
USE AND VEGETATION: Most of the soil is used for pasture or woodland. Pastures are mainly in coastal bermudagrass or weeping lovegrass. Native trees include loblolly pine, shortleaf pine, red oak, and hickory. Watermelons, peanuts, small grain for grazing, and vegetables are grown in some areas.
DISTRIBUTION AND EXTENT: Eastern Texas, Arkansas, and Mississippi. The series is extensive.
MLRA OFFICE RESPONSIBLE: Little Rock, Arkansas
SERIES ESTABLISHED: Anderson County, Texas; 1970.
REMARKS: These soils were formerly included in the Lakeland and Troup series. The series was updated in 2002 to allow value 6 in the Bt horizon and to allow clay loam texture below 60 inches deep. The series was updated in 2004 to allow 7.5YR hue in the E and EB horizons.
Diagnostic horizons and features recognized in this pedon are:
Ochric epipedon - the zone from the surface to a depth of 46 inches (Ap, E1, E2, E3, horizons) - thickness and texture results in Grossarenic subgroup.
Argillic horizon - the zone from approximately 46 to 86 inches (Bt1, Bt2, Bt3 horizons)
ADDITIONAL DATA: NSSL data from Type location S74TX-001-1.