LOCATION ZUMMO TXEstablished Series
TAXONOMIC CLASS: Fine, smectitic, hyperthermic Vertic Endoaquolls
TYPICAL PEDON: Zummo muck--rangeland.
(Colors are for moist soil unless otherwise stated.)
Oa--0 to 8 inches; very dark gray (10YR 3/1) muck; massive; about 25 percent fiber, 5 percent rubbed; very fluid, flows easily between fingers leaving mainly roots in hand (n-value of 1.0 to 2.0); many medium roots; strongly acid; clear wavy boundary. (5 to 15 inches thick)
A1--8 to 16 inches; black (10YR 2/1) clay; weak coarse prismatic structure parting to moderate medium subangular blocky; hard, firm; many fine and medium roots; few fine pores; very strongly acid; clear wavy boundary.
A2--16 to 24 inches; very dark gray (10YR 3/1) clay; moderate medium prismatic structure parting to moderate medium subangular blocky; hard, firm; common fine and medium roots; common fine prominent dark gray (10YR 4/1) iron depletions; few very dark gray (10YR 3/1) krotovina; strongly acid; gradual wavy boundary. (combined thickness of the A horizon is 10 to 24 inches)
Bg1--24 to 34 inches; dark gray (10YR 4/1) clay; moderate medium prismatic structure parting to moderate medium subangular blocky; hard, firm; common fine prominent brownish yellow (10YR 6/6) masses of iron accumulation; common fine roots; few very dark gray (10YR 3/1) krotovina; slightly acid; gradual wavy boundary.
Bg2--34 to 46 inches; gray (10YR 6/1) clay; moderate medium prismatic structure parting to moderate medium subangular blocky; hard, firm; few fine roots; common fine prominent brownish yellow (10YR 6/6) masses of iron accumulation; few very dark gray (10YR 3/1) krotovina; slightly acid; gradual wavy boundary.
Bg3--46 to 66 inches; light gray (10YR 7/1) clay; moderate medium prismatic structure parting to moderate fine subangular blocky; hard, firm; few fine roots; common fine prominent brownish yellow (10YR 6/6) masses of iron accumulation; few very dark gray (10YR 3/1) krotovina; neutral; gradual wavy boundary.
Bg4--66 to 80 inches; light gray (2.5Y 7/1) clay; moderate medium prismatic structure parting to moderate fine subangular blocky; few fine roots; common fine prominent yellowish brown (10YR 5/8) masses of iron accumulation; few iron-manganese concretions 5 to 10 mm in size; few very dark gray (10YR 3/1) krotovina; neutral; gradual wavy boundary. (combined thickness of the Bg horizons is 30 to 60 inches)
TYPE LOCATION: Jefferson County, Texas; from the intersection of Texas Highways 823 and 73 in west Port Arthur; 9.15 miles west on Texas Highway 73; 4.0 miles south, 1.5 mile northeast, and 0.25 mile north on private road; 300 feet west in marsh. (Latitude 29N, 48, 13; Longitude 94W, 06, 14)
RANGE IN CHARACTERISTICS: Solum thickness is greater than 80 inches. Thickness of the surface layer with n-value greater than 0.7 is less than 16 inches. The thickness of the mollic epipedon, excluding horizons with n-values of 0.7 or more, is 10 to 24 inches. The electrical conductivity is less than 2 dS/m throughout.
The Oa horizon has colors in shades of black and gray with hue of 10YR to 5Y, value of 2 or 3, and chroma of 2 or less. The texture is muck or mucky peat. Reaction ranges from very strongly acid to moderately acid. N-value ranges from 0.7 to 2.0.
The A horizons have colors in shades of black and gray with hue 10YR to 5Y, value of 2 to 4, and chroma of 2 or less. Iron accumulations are few to common in shades of brown or yellow. Texture is clay or silty clay. Reaction ranges from extremely acid to moderately acid.
The Bg1 and Bg2 horizons have hue in shades of gray on hue 10YR to 5GY, values of 4 to 6, and chroma of 1 or less. Iron accumulations are in shades of brown or yellow. Iron depletions are few to common in shades of gray. Texture is clay or silty clay. Reaction ranges from very strongly acid to slightly acid.
The Bg3 and Bg4 horizons have hue in shades of gray on hue 10YR to 5GY, values of 6 to 7, and chroma of 1 or less. Iron accumulations are in shades of brown or yellow. Iron-manganese concretions range from none to common. Texture is clay or silty clay. Reaction ranges from strongly acid to neutral.
COMPETING SERIES: There are no competing series. Similar soils are the Ged and Harris series. The Harris series is saline throughout and does not have a histic epipedon. The Ged series is in a very-fine family, is more alkaline in the subsoil, and has an argillic horizon.
GEOGRAPHIC SETTING: Zummo soils are on the landward side of low freshwater Gulf Coast marshes. Slope is less than 1 percent. The soil formed in clayey sediments of Holocene age. Mean annual rainfall ranges from 50 to 62 inches. Mean annual temperature ranges from 70 to 72 degrees F. Frost free days range from 250 to 270. Elevation ranges from 0 to 2 feet. The Thornthwaite P-E index is 68 to 80.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the Allemands, Beaumont, and Meaton series. Allemands soils are at the same or slightly lower positions and have organic surface layers more than 16 inches thick. Beaumont and Meaton soils are on adjacent upland positions and are better drained. Beaumont soils have a ochric epipedon. Meaton soils have a fine-silty particle-size control section.
DRAINAGE AND PERMEABILITY: Zummo soils are very poorly drained. Runoff is negligible. Permeability is very slow. The water level fluctuates between 0 to 1.5 foot above the soil surface throughout the year. These soils have aquic conditions in all years. They are frequently flooded by storm tides.
USE AND VEGETATION: Used mainly for wildlife habitat and range. The vegetation consists of maidencane, giant cutgrass, common reed, switchgrass, California bulrush, cattail, Jamaica sawgrass, seashore paspalum, knotroot bristlegrass, and torpedograss.
DISTRIBUTION AND EXTENT: The Gulf Coast Marsh (MLRA 151) of southeast Texas and possibly southwest Louisiana. The series is of minor extent.
MLRA OFFICE RESPONSIBLE: Temple, Texas
SERIES ESTABLISHED: Jefferson County, Texas; 1996.
REMARKS: The Zummo soils were formerly included with the Harris series.
Diagnostic horizons and features recognized in this pedon are:
Sapric soil materials - 0 to 8 inches (Oa horizon).
Mollic epipedon - 8 to 24 inches (A1 and A2 horizons).
Endosaturation - 0 to 80 inches. The soil is saturated with water in all layers to a depth of 80 inches or more from the mineral soil surface.
Aquic features - Redoximorphic features, reduction, and saturation throughout the pedon most of the time in all years.
Vertic features - Linear extensibility of 6.0 cm or more between the mineral soil surface and a depth of 40 inches.
SOIL INTERPRETATION RECORD NUMBER: TX1304