LOCATION SACRAMENTO CAEstablished Series
TAXONOMIC CLASS: Very-fine, smectitic, thermic Cumulic Vertic Endoaquolls
TYPIFYING PEDON: Sacramento clay - cultivated (Colors are for dry soil unless otherwise noted.)
Apg--0 to 7 inches; gray (5Y 5/1) clay, very dark gray (5Y 3/1) moist; common fine prominent strong brown (7.5YR 5/6) mottles, reddish brown (5YR 4/4) moist; strong medium and coarse angular blocky structure parting to moderate coarse granular structure; hard, firm sticky, very plastic; few very fine roots; common very fine tubular pores; medium acid (pH 6.0); abrupt smooth boundary. (6 to 10 inches thick)
A12g--7 to 16 inches; gray (5Y 5/1) clay, very dark gray (5Y 3/1) moist; many medium prominent strong brown (7.5YR 5/6) mottles, dark reddish brown (5YR 3/4) moist; massive (probable tillage pan); hard, very firm, sticky, very plastic; few very fine roots; common very fine tubular pores; continuous pressure faces; neutral (pH 6.7); clear wavy boundary. (2 to 10 inches thick)
A13g--16 to 31 inches; gray (5Y 5/1) clay, very dark gray (5Y 3/1) moist; common fine prominent strong brown (7.5YR 5/6) mottles, brown (7.5YR 4/4) moist; moderate coarse prismatic structure parting to moderate coarse angular blocky structure; hard, firm, sticky, very plastic; common very fine and few fine roots; many very fine tubular pores; continuous pressure faces; few iron colored bands less than 1 inch thick; very slightly effervescent, disseminated lime; mildly alkaline (pH 7.5); diffuse boundary. (10 to 20 inches thick)
A14g--31 to 38 inches; mottled gray (5Y 5/1), light olive gray (5Y 6/2) and strong brown (7.5YR 5/6) clay, very dark gray (5Y 3/1), olive (5Y 5/3), and reddish brown (5YR 4/4) moist; moderate coarse prismatic structure parting to moderate coarse angular blocky structure; hard, very firm, sticky, very plastic; common very fine and few fine roots; many very fine tubular pores; continuous pressure faces; very slightly effervescent disseminated lime; moderately alkaline (pH 7.9); clear wavy boundary. (6 to 10 inches thick)
A15g--38 to 53 inches; gray (5Y 5/1) clay, very dark gray (5Y 3/1) and olive gray (5Y 5/2) moist; common fine prominent strong brown (7.5YR 5/6) mottles, reddish brown (5YR 4/4) moist; moderate coarse angular blocky structure; hard, very firm, sticky, very plastic; common very fine and few fine roots; common very fine tubular pores; continuous pressure faces; very slightly effervescent disseminated lime; moderately alkaline (pH 7 .9); clear wavy boundary. (12 to 17 inches thick)
Clg--53 to 60 inches; gray (5Y 5/1) clay, very dark gray (5Y 3/1) and olive gray (5Y 5/2) moist; common fine prominent strong brown (7.5YR 5/6) mottles, reddish brown (5YR 4/4) moist; massive; hard, firm, sticky, very plastic; few very fine roots; many very fine tubular pores; continuous pressure faces; very slightly effervescent; disseminated lime; mildly alkaline (pH 7. 8); abrupt wavy boundary . (4 to 8 inches thick)
C2g--60 to 69 inches; gray (5Y 5/1) clay, very dark gray (5Y 3/1) and olive gray (5Y 5/2) moist; many fine prominent strong brown (7.5YR 5/6) mottles, dark reddish brown (5YR 3/3) moist; massive; hard, firm, sticky, very plastic; few very fine roots; many very fine tubular pores; continuous pressure faces; very slightly effervescent disseminated lime; mildly alkaline (pH 7. 7); clear wavy boundary. (5 to 10 inches thick)
C3g--69 to 77 inches; mottled light gray and gray (5Y 6/1), light brownish gray (2 .5Y 6/2), and strong brown (7.5YR 5/8) silty clay, gray (5Y 5/1), olive (5Y 5/3), and reddish brown (5YR 4/4) moist; massive; hard, firm, slightly sticky, very plastic; few very fine roots; many very fine tubular pores; continuous pressure faces; moderately alkaline (pH 7.9).
TYPE LOCATION: Yolo County, California- 100 feet east of the intersection of State Highway 45 and County Road 112; about 2.25 miles NW of Knights Landing; projected sec. 3, T.llN., R.2E (38 degrees N, 49 minutes, 37 seconds and 121 degrees W, 44 minutes, 53 seconds, Knights Landing quadrangle, 7.5 minute series)
RANGE IN CHARACTERISTICS: Distinct or prominent mottles in a matrix with chroma of 1 or less occur less than 10 inches below the surface. Clay content to a depth of 40 inches or more ranges from 60 to 70 percent. Unless irrigated, cracks develop to a depth of more than 20 inches and cracks are 3/8 to 1 inch or more wide. Some slickensides may be present, but if present, are too few to intersect. Organic matter content is 3 to 5 percent in the upper 20 inches, 1 to 3 percent above 40 inches, and 0.5 to 1 percent above 50 inches. The mean soil temperature at a depth of 20 inches is 64 degrees to 67 degrees F.
The A horizon ranges from gray (5Y 5/1, N 5/ , lOYR 5/1) to dark gray (5Y 4/1, N 4/ , lOYR 4/1). In areas where rice has been grown for many years, the chroma may increase to 2 with the above hues and values. This horizon ranges from medium acid to neutral in the upper 10 inches. The reaction in any one area may be determined by water management and by soil amendments. Lower Al horizons are mildly to moderately alkaline and slightly to strongly calcareous below a depth of 15 to 20 inches.
The C horizon ranges from light gray to greenish gray in hues of 2.5Y, 5Y, 5GY or 5G. It is silty clay or clay ana has stratified horizons of loam and clay loam below 40 inches in some pedons.
Buried A horizons are common. This horizon ranges from mildly to moderately alkaline and most pedons are calcareous in the C horizons.
COMPETING SERIES: These are the Clear Lake, Merritt, Omni, Ryde, Stockton, Sunnyvale, and Willows series. Clear Lake, Stockton, and Willows soils have intersecting slickensides and other soil properties indicative of soil churning. Merritt soils have 18 to 30 percent clay in the control section. Omni soils have mollic epipedons less than 20 inches thick and have less than 35 percent clay in the control section. Ryde soils have more than 10 percent organic matter in the A horizon and less than 35 percent clay. Sunnyvale soils have more than 15 percent calcium carbonate in or immediately below the lower A horizon.
GEOGRAPHIC SETTING: Sacramento soils are in nearly level basins at elevations of near sea level to 60 feet. The soils formed in fine textured alluvium of mixed origin. The climate is dry subhumid, mesothermal with hot dry summers and cool moist winters. Mean annual precipitation is 15 to 19 inches. Average January temperature is 45 degrees F., average July temperature is 75 degrees F., and mean annual temperature is 60 degrees F. Average frost-free season is over 275 days.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the competing Clear Lake, Merritt, Omni, Stockton, and Willows soils and the Capay, Columbia, and Sycamore soils. Capay soils have chroma of 2 or more and lack mottles associated with wetness. Columbia soils have pale brown color and less than 18 percent clay. Sycamore soils have less than 35 percent clay and the surface horizons are hard and massive.
DRAINAGE AND PERMEABILITY: Natural drainage is poor to very poor. Altered drainage occurs in reclamation districts and areas protected by levees, thus improving the drainage. The water table fluctuates between a depth of 34 inches to below 60 inches. Surface runoff is very slow to slow. Permeability is slow. Subject to frequent overflow where not protected by levees or located within flood control systems.
USE AND VEGETATION: Under cultivation, rice, safflower, and a variety of row crops. Alfalfa and orchards are grown if water table is low enough. Uncultivated areas now contain stands of willows, cottonwoods, scattered oaks, and grasses and forbs. Originally, vegetation consisted of tules, marsh grass, and other water-loving plants,
DISTRIBUTION AND EXTENT: This soils occurs in Sacramento and northern San Joaquin Valleys and is moderately extensive.
MLRA OFFICE RESPONSIBLE: Davis, California
SERIES ESTABLISHED: Sacramento Area, California, 1904.
REMARKS: The Sacramento soils were formerly classified as Humic Gley soils.
OSED scanned by SSQA. Last revised by state on 6/72.
Series reclassified 5/95. Competing series not updated at that time.
ADDITIONAL DATA: NSSL pedon S64CA-113-010 (type location) and S64CA-113-011