LOCATION LOFGREN CAEstablished Series
TAXONOMIC CLASS: Very-fine, smectitic, thermic Xeric Epiaquerts
TYPICAL PEDON: Lofgren clay on a less than 1 percent slope, under a cover of rice at an elevation of 83 feet, (25 m). When described 5/2/1995, the soil was moist throughout, water table at 43 inches, (109 cm). (Colors are for dry soil unless otherwise stated).
Ap--0 to 5 inches, (0 to 13 cm); dark gray (10YR 4/1) clay, very dark gray (10YR 3/1) moist; 56 percent clay; weak medium subangular blocky structure parting to strong fine granular; very hard, very firm, very sticky and very plastic; many fine roots; common fine irregular pores; many fine brown (7.5YR 4/4) oxidized iron masses; non-effervescent; strongly acid, pH 5.1 by pH meter 1:1 water; abrupt smooth boundary. (5 to 8 inches, (13 to 20 cm) thick)
Bssg1--5 to 12 inches, (13 to 31 cm); dark gray (10YR 4/1) clay, 50 percent very dark gray (10YR 3/1) and 50 percent dark gray (N 4/0) moist; 65 percent clay; weak medium angular blocky structure; extremely hard, very firm, very sticky and very plastic; few very fine and fine roots; few very fine tubular pores; common slickensides; common fine dark brown (7.5YR 3/3) oxidized iron masses and common fine gray (10YR 5/1) iron depletions; non-effervescent; neutral, pH 6.7 by pH meter 1:1 water; clear smooth boundary.
Bssg2--12 to 29 inches, (31 to 74 cm); dark gray (10YR 4/1) clay, dark gray (10YR 4/1) moist; 66 percent clay; moderate coarse prismatic structure; extremely hard, extremely firm, very sticky and very plastic; few very fine roots; few very fine tubular pores; common slickensides; common fine gray (10YR 5/1) iron depletions; non-effervescent; slightly alkaline, pH 7.5 by pH meter 1:1 water; clear smooth boundary. (Combined thickness of the Bssg horizon is 10 to 24 inches (25 to 61 cm) thick).
Bkssg--29 to 38 inches, (74 to 97 cm); grayish brown (10YR 5/2) clay, dark gray (10YR 4/1) moist; 65 percent clay; moderate fine angular blocky structure; extremely hard, firm, very sticky and very plastic; common very fine tubular pores; few slickensides; common fine carbonate threads, common fine gray (10YR 5/1) iron depletions; strongly effervescent; moderately alkaline, pH 8.1 by pH meter 1:1 water; abrupt smooth boundary.(9 to 16 inches (23 to 41 cm) thick)
Bkg--38 to 44 inches, (97 to 112 cm); very pale brown (10YR 8/2) clay, dark gray (10YR 4/1) moist; 61 percent clay; moderate fine prismatic structure parting to weak fine angular blocky; extremely hard, firm, very sticky and very plastic; common very fine tubular pores; common fine carbonate threads and common fine gray (10YR 5/1) iron depletions; strongly effervescent; moderately alkaline, pH 8.5 by pH meter 1:1 water; abrupt wavy boundary.
2Bkq--44 to 47 inches, (112 to 119 cm); light gray (10YR 7/2) clay loam, dark grayish brown (10YR 4/2) moist; 29 percent clay; moderate medium angular blocky structure; very rigid, firm, moderately cemented; moderately sticky and moderately plastic few very fine and fine tubular pores; common fine carbonate threads; strongly effervescent; strongly alkaline, pH 8.5 by pH meter 1:1 water; abrupt smooth boundary. (Combined thickness of the Bkg horizons is 9 to 16 inches (23 to 41) thick).
2Bkqm1--47 to 62 inches, (119 to 158 cm); indurated duripan; light gray (10YR 7/2) sandy loam, brown (7.5YR 4/4) moist; 16 percent clay; massive; very rigid; nonsticky and nonplastic; few very fine and fine tubular pores; common fine carbonate threads; strongly effervescent; strongly alkaline, pH 8.7 by pH meter 1:1 water; abrupt smooth boundary. Alternating layers of cementation, with lime and silica filaments. Indurated capping at 47 inches, with very thin layer of sand on top of capping. Capping has lime and silica threads.
2Bkqm2--62 to 82 inches, (158 to 208 cm); strongly cemented duripan; pink (7.5YR 7/4) loam, brown (7.5YR 4/4) moist; 17 percent clay; massive; very rigid; nonsticky and slightly plastic; strongly effervescent; moderately alkaline, pH 8.4 by pH meter 1:1 water.
TYPE LOCATION: Butte County, California; about 4.2 miles southwest of Richvale, approximately 200 feet east and 1100 feet north of the southwest corner of Section 25, Township 19 N., Range 1 E., 39 degrees, 28 minutes, 2 seconds North latitude and 121 degrees, 49 minutes, 4 seconds West longitude, NAD27. U.S.G.S. Quad: West of Biggs, California.
RANGE IN CHARACTERISTICS: Depth to duripan is 40 to 60 inches, (102 to 152 cm). The mean annual soil temperature is 62 to 66 degrees F, (17 to 19 degrees C). The soil moisture control section is dry from July to October (120 to 125 days). The particle-size control section averages 60 to 70 percent clay. The soil is calcareous from 29 to 60 inches, (74 to 152 cm). Calcium carbonate ranges from trace amounts to 11 percent. Base saturation by ammonium acetate ranges from 80 to 100 percent from 0 to 12 inches, (0 to 31 cm) and is 100 percent to a depth of 82 inches, (208 cm). Electrical conductivity is less than 1 mmhos/cm throughout. Reversible surface-initiated cracks 1 to 2 inches, (2.54 to 5 cm) wide extend to a depth of 30 to 35 inches, (76 to 89 cm) from May 15 to October 15 (150 days) when the soil is not irrigated. Common slickensides are in the Bssg1, Bssg2 and Bsskg horizons at 5 to 38 inches, (13 to 97 cm). A fluctuating water table can occur between the top of the duripan and the surface of the soil from December through May. Redoximorphic features such as manganese nodules, oxidized iron masses with colors of 7.5YR 4/4 or N 2/0 and reduced matrix with chroma of 1 occur in horizons above the duripan. Some pedons lack a 2Bkq horizon.
The Ap horizon dry color is 10YR 3/1 or 4/1. Moist color is 10YR 2/1 or 3/1. Clay content ranges from 60 to 70 percent. Organic matter ranges from 1 to 3 percent. Reaction ranges from slightly acid to strongly acid due to applications of fertilizer. Exchangeable sodium ranges from 1 to 2 percent.
The Bssg horizon dry color is 10YR 3/1, 4/1 or 5/1. Moist color is 10YR 3/1, 4/1 or N 4/0. Clay content ranges from 60 to 70 percent. Organic matter ranges from 0.5 to 1 percent. Reaction is slightly alkaline to moderately alkaline. Exchangeable sodium ranges from 1 to 2 percent.
The Bkssg horizon dry color is 10YR 3/1, 4/1 or 5/2. Moist color is 10YR 3/1, 3/2, 4/1 or 4/2. Clay content ranges from 60 to 70 percent. Organic matter ranges from .5 to 1 percent. Reaction is slightly alkaline to moderately alkaline. Exchangeable sodium ranges from 2 to 3 percent.
The Bkg horizon dry color is 10YR 5/1, 5/2, 6/2, 7/2 or 8/2. Moist color is 10YR 4/1 or 4/2. Texture is clay or silty clay. Clay content ranges from 50 to 60 percent clay. Organic matter ranges from 0.1 to 1 percent. Reaction is moderately alkaline to strongly alkaline. Exchangeable sodium ranges from 2 to 3 percent.
2Bkq horizon dry color is 10YR 5/2, 6/2, 7/2 or 8/2. Moist color is 10YR 4/2 or 5/2. Texture is clay loam or silty clay loam. Clay content ranges from 27 to 40 percent. Organic matter ranges from 0.1 to 1 percent. Reaction is moderately alkaline to strongly alkaline. Exchangeable sodium ranges from 2 to 3 percent.
The 2Bkqm horizon dry color is 10YR 5/2, 6/2, 7/2, 7/3 or 7.5YR 7/4. Moist color is 10YR 4/2, 4/3, 5/2 or 7.5YR 4/4. Rupture resistance ranges from indurated to strongly cemented with alternating moderately to weakly cemented layers, cemented with silica and calcium carbonate. Calcium carbonate ranges from 2 to 11 percent. Exchangeable sodium ranges from 3 to 4 percent.
COMPETING SERIES: There are no other series in this family.
GEOGRAPHIC SETTING: Lofgren soils are in flood basins. Slopes range from 0 to 1 percent. These soils formed in alluvium from mixed rocks. Elevation is 58 to 110 feet, (18 to 34 m). The mean annual precipitation is 18 to 20 inches, (457 to 508 mm). The mean annual temperature is 59 to 61 degrees F, (15 to 16 degrees C). Frost free season is 240 to 245 days.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the Blavo, Neerdobe and Esquon soils. Blavo soils are moderately deep to a duripan and are mapped in complex with Lofgren. Esquon soils are deep to duripan and are fine. Neerdobe soils are moderately deep to a duripan and are fine.
DRAINAGE AND PERMEABILITY: Poorly drained; high runoff; very slow saturated hydraulic conductivity in the Ap, Bssg and Bkssg horizons, slow in the Bkg horizon, moderately slow in the 2Bkq horizon and impermeable in the 2Bkqm horizon. The soils are rarely to occasionally flooded for very brief to brief periods from December through March. A fluctuating water table can occur between the top of the duripan and the surface of the soil from December through May. Water frequently ponds up to 6 inches, (15 cm) above the surface for long duration from December through April. Dams, levees, drainage ditches, and leveling for agriculture have modified the frequency and duration of saturation, ponding and flooding.
USE AND VEGETATION: This soil is used for rice production and wildlife habitat. The natural vegetation is grasses, sedges and other hydrophytic plants.
DISTRIBUTION AND EXTENT: Butte County, California. MLRA 17 - Sacramento Valley. The soils are moderately extensive.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Davis, California
SERIES ESTABLISHED: Butte County, California, 2005. Source of name from Lofgren Road on the West of Biggs Quad.
REMARKS: Diagnostic horizons and features recognized in this pedon are:
Mollic epipedon - 0 to 12 inches, (0 to 31 cm) (Ap, Bssg1).
Cambic horizon - 12 to 47 inches, (31 to 119 cm) (Bssg2, Bkssg, Bkg, 2Bkq).
Duripan - 47 to 82 inches, (119 to 208 cm) (2Bkqm1, 2Bkqm2).
Lithologic discontinuity - 44 inches, (112 cm).
Redoximorphic Features - from 0 to 47 inches, (0 to 119 cm).
Particle-size control section - 10 to 40 inches, (25 to 102 cm).
Moisture control section 8 to 23 inches, (20 to 58 cm).
Clay mineralogy is dominantly smectitic with lesser amounts of kaolinite and vermiculite.
This soil was previously mapped as Stockton clay adobe in the Soil Survey of the Oroville Area, California 1926.
ADDITIONAL DATA Characterization data from lab pedon number: 95P0510, NSSL, Lincoln, NE