LOCATION TAMBA CAEstablished Series
TAXONOMIC CLASS: Fine, mixed, superactive, acid, thermic Fluvaquentic Endoaquepts
TYPICAL PEDON: Tamba mucky clay - waterfowl hunting area (Colors are for dry soil unless otherwise noted.)
A11--0 to 5 inches; light brownish gray (10YR 6/2) mucky clay, very dark grayish brown (10YR 3/2) moist; common medium distinct light yellowish brown (10YR 6/4) dry mottles; weak fine and medium crumb structure; slightly hard, friable, sticky, plastic; many very fine roots; many very fine pores; strongly acid (pH 5.5); clear smooth boundary. (4 to 8 inches thick)
A12--5 to 10 inches; mottled grayish brown and yellowish brown (10YR 5/2, 5/4) mucky clay, very dark brown and dark yellowish brown (10YR 2/2, 3/4) moist; weak fine crumb structure; slightly hard, friable, slightly sticky, slightly plastic; common very fine roots; common very fine pores; very strongly acid (pH 4.5); abrupt smooth boundary. (3 to 6 inches thick)
B21g--10 to 31 inches; gray (N 6/) and black (10YR 2/1) mucky clay, black (10YR 2/1) moist; few fine prominent mottles of yellowish red (5YR 5/8) dry, dark red (2.5YR 3/6) moist; massive; slightly hard, friable, sticky, plastic; common very fine roots; common very fine pores; very strongly acid (pH 4.5); diffuse wavy boundary. (8 to 24 inches thick)
B22g--31 to 52 inches; gray (N 6/) and black (10YR 2/1) mucky clay, very dark brown (10YR 2/2) moist; few fine prominent mottles of dark brown (7.5YR 3/2) dark brown (7.5YR 3/2) moist; massive; slightly hard, friable, sticky, plastic; few very fine roots; common very fine pores; very strongly acid (pH 4.5); gradual wavy boundary. (12 to 22 inches thick)
Cg--52 to 78 inches; gray (N 6/) mucky clay, dark greenish gray (5BG 4/1) moist; massive; slightly hard, firm, very sticky, plastic; many fine tubular pores; strong odor of H2S, moderately alkaline (pH 8.0), becomes acid when exposed to air for a few weeks. (12 to 30 inches thick)
TYPE LOCATION: Solano County, California; about 1 3/4 miles north and 2 1/2 miles west of Collinsville; 5/8 mile west of boat ramp located at east side of Grizzly Island on Montezuma Slough.
RANGE IN CHARACTERISTICS: The mean annual soil temperature at a depth of 20 inches is about 63 degrees F. Under natural conditions, the soil is moist in all horizons at all times. Soil drainage has been altered on much of this soil allowing the soil to seasonally dry as deep as 20 inches; cracks develop and the soil oxidizes. The soil reaction varies with the amount of oxidation as influenced by drainage. Organic matter ranges from 15 to 30 percent in the 10 to 40 inch control section. Thin lenses of fibrous organic matter may occur in lower horizons. The 10 to 40 inch control section is clay, silty clay or mucky clay with 35 to 50 percent clay. The electrical conductance ranges from 15 to 50 millimhos per centimeter at 25 degrees C.
The A horizon has hue of 10YR or neutral, dry value of 4 through 6 and moist value of 2 or 3, and chroma of 1 or 2. It usually has dry value of 6 in the upper part and has distinct or prominent mottles in some or all parts. This horizon is strongly to very strongly acid.
The Bg horizon has chroma of 1 or less and prominent yellowish or reddish mottles. It is medium to very strongly acid. It has distinct yellow efflorescence of jarosite in some pores. Lower Bg and C horizons smell strongly of H2S.
The C horizons are similar to Bg horizons.
COMPETING SERIES: These are the Alviso, Joice, Reyes, and Una series. Alviso soils are neutral to mildly alkaline in the 10 to 20 inch section. Joice soils have 30 to 50 percent organic matter in the 10 to 40 inch section. Una soils lack the high salinity, jarosite, and other characteristics associateed with effects of salt water. Also, they have less than 15 percent organic matter.
GEOGRAPHIC SETTING: The Tamba soils are in flat salt water marshes near sea level. They formed in mixed alluvium and hydrophytic plant remains. The climate is Mediterranean with a mean annual precipitation of 15 to 20 inches, hot dry summers and cool moist winters. The mean annual temperature is about 59 degrees F., average January temperature is about 46 degrees F., and average July temperature about 72 degrees F. Freeze-free season is about 260 to 280 days.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the competing Joice and Reyes soils and the Suisun soils. Suisun soils have 50 percent or more organic matter.
DRAINAGE AND PERMEABILITY: Tamba soils were formed under very poor drainage, but under present management, these soils have altered drainage. The water table varies with the management of levees and tide gates, usually being near 3 feet in mid-summer and near the surface in winter months. Runoff is very slow or ponded and permeability is moderate.
USE AND VEGETATION: Used largely for waterfowl hunting, but some areas are used for livestock pasture. Vegetation is salt-tolerant forbs and several members of the rush and sedge families.
DISTRIBUTION AND EXTENT: In Suisan Marsh, Solano County, California. The series is of minor extent.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Davis, California
SERIES ESTABLISHED: Solano County, California, 1969.
REMARKS: The Tamba soils would most nearly have been classed as Half Bog soils. The classification was updated in February 2001 using the Eighth Edition to Soil Taxonomy. This series was formerly classified as fine, mixed, acid, thermic Typic Halaquepts. Competing series were not checked at that time.
OSED scanned by SSQA. Last revised by state on 5/72.