LOCATION EDCO TXEstablished Series
TAXONOMIC CLASS: Fine, mixed, active, hyperthermic Aquertic Chromic Hapludalfs
TYPICAL PEDON: Edco fine sandy loam--rice field. (Colors are for moist soil unless otherwise stated.)
Ap1--0 to 4 inches; dark grayish brown (10YR 4/2) fine sandy loam, pale brown (10YR 6/3) dry; weak medium subangular blocky structure; soft, friable, slightly sticky and slightly plastic; many fine roots; 1 percent siliceous pebbles; common fine pores; many fine and medium faint dark gray (10YR 4/1) iron depletions with diffuse boundaries on surfaces of peds; common fine faint dark yellowish brown rhizospheres; moderately acid; clear wavy boundary. ( 4 to 12 inches thick)
Ap2--4 to 7 inches; dark gray (10YR 4/1) fine sandy loam, light brownish gray (10YR 6/2) dry; weak medium subangular blocky structure parting to weak fine subangular blocky; slightly hard, friable, slightly sticky and slightly plastic; many fine roots; few fine masses of iron-manganese; 1 percent siliceous pebbles; many fine faint dark yellowish brown (10YR 4/4) masses of iron accumulation with clear boundaries of surfaces of peds; neutral; abrupt wavy boundary. ( 0 to 8 inches thick)
Bt1--7 to 14 inches; dark grayish brown (10YR 4/2) clay, grayish brown (10YR 5/2) dry; strong fine and medium angular blocky structure; very hard, extremely firm, very sticky and very plastic; common fine roots; few distinct pressure faces and wedged-shaped aggregates; few vertical cracks 5 to 10 mm wide partly filled with material from above; many distinct clay films on surfaces of peds; 1 percent siliceous pebbles; few fine faint dark yellowish brown, few fine distinct strong brown (7.5YR 5/6) and common medium and coarse distinct yellowish brown (10YR 5/6) masses of iron accumulation with sharp boundaries on surfaces of peds; neutral; clear smooth boundary.
Bt2--14 to 31 inches; grayish brown (2.5Y 5/2) sandy clay, light brownish gray (2.5Y 6/2) dry; moderate fine and medium angular blocky structure; very hard, extremely firm, very sticky and very plastic; common fine roots; few distinct pressure faces and wedged-shaped aggregates; few vertical cracks 5 to 10 mm wide partly filled with material from above; many distinct clay films on surfaces of peds; 1 percent siliceous pebbles; few fine distinct yellowish brown (10YR 5/6) and many medium and coarse faint light olive brown (2.5Y 5/4) masses of iron accumulation with clear and sharp boundaries on surfaces of peds; common medium and coarse dark grayish brown (10YR 4/2) iron depletions with diffuse boundaries on surfaces of peds; neutral; clear smooth boundary.
Bt3--31 to 44 inches; grayish brown (2.5Y 5/2) sandy clay loam, light brownish gray (2.5Y 6/2) dry; moderate medium angular blocky structure; very hard, extremely firm, very sticky and very plastic; many distinct clay films on surfaces of peds; few fine concretions of iron-manganese; 2 percent siliceous pebbles; common medium faint light olive brown (2.5Y 5/4) masses of iron accumulation with clear boundaries; neutral; clear smooth boundary. (combined thickness of the Bt horizons is 15 to 50 inches)
Btk--44 to 56 inches; light brownish gray (2.5Y 6/2) sandy clay loam, light gray (2.5Y 7/2) dry; strong coarse subangular blocky structure; very hard, extremely firm, very sticky and very plastic; common distinct clay films on surfaces of peds; few fine concretions of iron-manganese; common fine to coarse concretions of calcium carbonate; 2 percent siliceous pebbles; few fine distinct brown (10YR 5/3), strong brown (7.5YR 5/6) and common medium distinct light yellowish brown (2.5Y6/4) masses of iron accumulation with clear and sharp boundaries on surfaces of peds; violently effervescent; moderately alkaline; clear smooth boundary. (0 to 15 inches thick)
BCtk--56 to 68 inches; light gray (10YR 7/2) sandy clay loam, white (2.5Y 8/2) dry; moderate medium subangular blocky structure; very hard, extremely firm, very sticky and very plastic; few faint clay films on surfaces of peds; few fine rounded concretions of iron-manganese; common fine to coarse rounded concretions of calcium carbonate; common fine and medium soft flakes and threads of manganese; 2 percent rounded siliceous pebbles; few fine and medium distinct yellowish brown (10YR 5/6) and many fine distinct brownish yellow (10YR 6/6) and yellow (10YR 7/6) masses of iron accumulation with sharp boundaries on surfaces of peds; violently effervescent; moderately alkaline; clear smooth boundary. (0 to 20 inches thick)
BCk1--68 to 74 inches; light gray (10YR 7/1) sandy clay loam, light gray (2.5Y 7/2) dry; moderate medium subangular blocky structure; very hard, extremely firm, very sticky and very plastic; few fine threads of iron-manganese; common fine and medium concretions of calcium carbonate; common fine and medium crystals and concretions of barite; 3 percent siliceous pebbles; common fine distinct brownish yellow (10YR 6/6) and common fine and medium distinct strong brown (7.5YR 5/6) masses of iron accumulation with sharp boundaries on surfaces of peds; violently effervescent; moderately alkaline; clear smooth boundary. ( 0 to 20 inches thick)
BCk2--74 to 80 inches; light gray (10YR 7/1) sandy clay loam, light gray (2.5Y 7/2) dry; weak medium subangular blocky structure; very hard, extremely firm, very sticky and very plastic; few fine masses of iron-manganese; common fine and medium concretions of calcium carbonate; many fine and medium crystals and concretions of barite; 3 percent siliceous pebbles; common fine and medium prominent yellowish red (5YR 5/8) and many fine and medium distinct brownish yellow (10YR 6/6) masses of iron accumulation with sharp boundaries on surfaces of peds; violently effervescent; moderately alkaline.
TYPE LOCATION: Colorado County, Texas, in Eagle Lake, from the intersection of U.S. Highway Alternate 90 and Farm Road 3013, 4.0 miles south on Farm Road 3013, 0.6 mile east on field road and 300 feet south in rice field; USGS Eagle Lake topographic quadrangle; Latitude: 29 degrees, 31 minutes, 43.5 seconds N; Longitude: 96 degrees, 18 minutes, 48.5 seconds W.
RANGE IN CHARACTERISTICS: Solum thickness ranges from 60 to more than 80 inches. The upper part of the argillic horizon cracks when dry.
The Ap or A horizon is less than 10 inches thick in more than 50 percent of any pedon, but ranges up to 12 inches thick. It has hue of 10YR, value of 4 or 5 and chroma of 1 to 3. When dry, this horizon is massive and very hard or extremely hard. Some pedons have an E horizon of higher value than the Ap or A horizon. Reaction ranges from moderately acid to neutral.
The Bt horizon has hue of 10YR or 2.5Y, values of 4 to 7 and chroma of 1 or 2. Texture is clay loam or clay in the upper Bt horizons and sandy clay loam, clay loam or sandy clay in the lower Bt horizons. The clay percent in the upper Bt horizons range from 35 to 55 percent and clay percent in the lower Bt horizons range from 27 to 40 percent. COLE ranges from 0.09 to 0.11. Redoximorphic features in shades of red, yellow, brown or olive range from few to common and are throughout the horizon. Coatings of darker colors are on surfaces of peds in some pedons. Concretions, masses, films and threads of calcium carbonate range from 0 to 5 percent. Reaction is moderately acid to neutral in the upper part and is slightly alkaline or moderately alkaline in the lower part.
The BCt horizon is mottled or has a grayish matrix with redoximorphic features in shades of red, yellow, brown or olive that range from few to common. Dominant colors are in hue of 7.5YR to 2.5Y, value of 4 to 7, and chroma of 2 to 6. Texture is sandy clay loam, clay loam or clay. Concretions, masses, films and threads of calcium carbonate range from none to common. Reaction ranges from slightly acid to moderately alkaline. Some pedons are calcareous.
The BCk horizon has hue of 2.5YR to 2.5Y, value of 4 to 7 and chroma of 1 to 8. Redoximorphic features in shades of red, yellow, brown or gray range from none to many. Texture ranges from sandy loam to clay. Concretions of calcium carbonate range from few to many. Reaction is slightly alkaline or moderately alkaline.
COMPETING SERIES: These are the Nez (TX) and Telf (TX) series. Similar soils are the Edna, Garwood, Inez, Katy, Mentz, Telferner, Texana, and Yeaton series. Nez and Telf soils have an ochric epipedon from 10 to 20 inches thick. Edna soils have smectitic mineralogy and formed from sediments of the Beaumont Formation. Garwood soils have an ochric epipedon 18 to 30 inches thick and have kaolinitic mineralogy. Inez and Telferner soils have an ochric epipedon from 10 to 20 inches thick and formed from sediments of the Beaumont Formation. Katy soils are in the fine-loamy family and have an ochric epipedon 18 to 30 inches thick. Mentz soils are in the thermic temperature regime and formed in materials weathered from the Goliad Formation. Texana soils have a mollic epipedon and formed from sediments of the Beaumont Formation. Yeaton soils are in the thermic temperature regime
GEOGRAPHIC SETTING: Edco soils are on broad, nearly level to very gently sloping coastal prairies. Slope ranges from 0 to 1 percent. The soil formed in clayey sediments of the Pleistocene age Lissie Formation. Mean annual temperatures ranges from 70 to 72 degrees F., and mean annual precipitation ranges from 40 to 44 inches. Frost free days range from 250 to 280 days, and elevation ranges from 170 to 250 feet. Thornthwaite annual P-E indices range from 52 to 62.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the Cieno, Katy, Nada, Nez, and Telf series. Cieno soils are in the fine-loamy family, have an aquic moisture regime and are in slightly lower oval depressions. Katy soils are in similar landscape positions. Nada soils are in the fine-loamy family and are on similar landscape positions. Nez and Telf soils are on similar landscape positions.
DRAINAGE AND PERMEABILITY: Somewhat poorly drained. Permeability is very slow. Runoff is low on 0 to 1 percent slopes. Water perches on top of the argillic horizon for periods of 2 to 4 weeks following extended heavy rain.
USE AND VEGETATION: Mainly used for rice production. Some areas are in native pasture. Native grasses are mainly prairie grasses of species of Andropogon, Paspalum, Panicum, and Sporobolus.
DISTRIBUTION AND EXTENT: Coastal Prairie of Texas MLRA 150A. The series is of minor extent.
MLRA OFFICE RESPONSIBLE: Temple, Texas
SERIES ESTABLISHED: Colorado County, Texas; 1997.
REMARKS: These soils were formerly included in the Edna series. This soil does not have an aquic moisture regime. The classification of Aquertic Chromic Hapludalfs is based on a study of similar soils where significant iron reduction and depletion has been measured in the A and, to a lesser extent, the upper part of the Bt horizon. Aquic conditions occur for periods long enough in most years to cause iron reduction and mobility, as well as iron oxidation. In addition, the majority of pedons have value moist of 4 or more and value dry of 6 or more, supporting the Chromic subgroup. The series classification supports mixed mineralogy and is based on reference samples tested for mineralogy by Texas A&M University.
Diagnostic horizons and features recognized in this pedon are:
Ochric epipedon - 0 to 7 inches. (Ap and A horizon)
Argillic horizon - 7 to 68 inches. (Bt1, Bt2, Bt3, Btk and BCtk horizons)
Aquertic feature - Cracks and/or wedge-shaped aggregates within the upper part of the argillic horizon. Intermittent aquic conditions are expressed by value of 5 and chroma of 1 or 2 in the matrix of the upper part of the argillic horizon, in association with masses of iron accumulation in this zone.
ADDITIONAL DATA: S97TX-089-13-2, Texas A&M University.