LOCATION WAFAP CAEstablished Series
TAXONOMIC CLASS: Clayey-skeletal, mixed, superactive, thermic Oxyaquic Argixerolls
TYPICAL PEDON: Wafap gravelly loam, on a west facing 1 percent slope under a cover of filaree and soft chess at an elevation of 312 feet, (95 m). When described on 4/2/97 the soil was dry to 1 inch, (3 cm); very slightly moist from 1 to 5 inches, (3 to 13 cm); and slightly moist to 46 inches, (117 cm). (Colors are for dry soil unless otherwise noted).
A--0 to 1 inches, (0 to 3 cm); brown (7.5YR 5/3) gravelly loam, dark reddish brown (5YR 3/3) moist; 22 percent clay; moderate medium platy parting to strong fine and medium subangular blocky structure; very hard, firm, slightly sticky, slightly plastic; many very fine roots; common very fine vesicular and tubular pores; 10 percent cobbles and 20 percent gravel; slightly acid, pH 6.5 by Hellige-Truog; clear smooth boundary. (1 to 4 inches, (3 to 10 cm) thick)
Bt1--1 to 5 inches, (3 to 13 cm); brown (7.5YR 4/3) cobbly clay loam, dark reddish brown (5YR 3/2) moist; 28 percent clay; moderate coarse columnar parting to strong medium subangular blocky structure; extremely hard, firm, slightly sticky, moderately plastic; common very fine roots around fragments; common very fine vesicular and tubular pores; 70 percent continuous distinct clay films on faces of peds; 15 percent cobbles and 15 percent gravel; neutral, pH 6.7 by Hellige-Truog; gradual smooth boundary.
Bt2--5 to 13 inches, (13 to 33 cm); brown (7.5YR 4/3) very cobbly clay loam, dark reddish brown (5YR 3/2) moist; 36 percent clay; moderate medium subangular blocky structure; very hard, friable, moderately sticky, moderately plastic; common very fine roots; common fine and very fine vesicular and tubular pores; 80 percent continuous distinct clay films on faces of peds; 5 percent stones, 10 percent gravel, and 25 percent cobbles; neutral, pH 7.0 by Hellige-Truog; clear wavy boundary.
Bt3--13 to 32 inches, (33 to 81 cm); brown (7.5YR 4/4) extremely cobbly clay loam, reddish brown (5YR 4/3) moist; 39 percent clay; moderate fine and medium subangular blocky structure; very hard, friable, very sticky, very plastic; common very fine roots; common very fine vesicular and tubular pores; 90 percent continuous distinct clay films on faces of peds and rock fragments; 5 percent stones, 25 percent gravel, and 50 percent cobbles; slightly alkaline, pH 7.5 by Hellige-Truog; clear wavy boundary.
Bt4--32 to 39 inches, (81 to 99 cm); brown (7.5YR 5/4) extremely cobbly clay loam, brown (7.5YR 4/4) moist; 38 percent clay; moderate fine and medium subangular blocky structure; moderately hard, friable, very sticky, very plastic; few very fine roots; common very fine vesicular and tubular pores; 90 percent continuous distinct clay films on faces of peds and rock fragments; 5 percent stones, 30 percent gravel, and 50 percent cobbles; moderately alkaline, pH 8.0 by Hellige-Truog; clear smooth boundary. (Combined thickness of the Bt horizon is 24 to 59 inches, (61 to 150 cm).
Btq--39 to 46 inches, (99 to 117 cm); light yellowish brown (10YR 6/4) extremely gravelly sandy clay loam, brown (7.5YR 5/4) moist; 30 percent clay; moderate fine subangular blocky structure; slightly hard, firm, weakly cemented by silica, moderately sticky, moderately plastic; common very fine vesicular and tubular pores; 90 percent continuous distinct clay films on faces of peds and rock fragments; 5 percent stones, 35 percent cobbles, and 40 percent gravel; moderately alkaline, pH 8.0 by Hellige-Truog; abrupt wavy boundary. (0 to 32 inches, (0 to 81 cm) thick)
2Bqm--46 inches, (117 cm); indurated duripan; cemented by silica.
TYPE LOCATION: Butte County, California, about 1.5 miles north of Rock Creek Road and 2.4 miles east of Meridian Road, approximately 2050 feet north and 2150 feet east of the southwest corner of Section 9, Township 23 N., Range 1 E., 39 degrees, 51 minutes, 40 seconds North latitude and 121 degrees, 52 minutes, 22 seconds West longitude, NAD27 - U.S.G.S Quad: Richardson Springs, California.
RANGE IN CHARACTERISTICS: Depth to duripan is 40 to 60 inches, (102 to 152 cm). The mean annual soil temperature is 62 to 68 degrees F, (17 to 20 degrees C). The particle-size control section averages 35 to 40 percent clay and 35 to 60 percent rock fragments, mostly gravel. Mineralogy is mixed. A fluctuating water table can occur between the top of the duripan and 13 inches below the surface of the soil from December through April. Redoximorphic features such as oxidized iron masses occur in the A and upper Bt horizons and iron-manganese masses occur in the Bt and Btq horizons. Rock fragments on the surface range from 0 to 5 percent gravel, 0 to 5 percent cobbles and 0 to 2 percent stones. Some pedons lack a Btq horizon. Some pedons have a 2Bt horizon.
The A horizon dry color is 7.5YR 4/3, 5/3 or 5YR 5/2. Moist color is 7.5YR 3/2, 3/3, 5YR 3/2 or 3/3. Texture is loam, gravelly loam or very gravelly sandy clay loam. Clay content ranges from 16 to 26 percent. Rock fragments range from 10 to 45 percent gravel and 0 to 10 percent cobbles. Reaction ranges from slightly acid to neutral.
The upper Bt horizon dry color is 7.5YR 4/3, 5/3, 6/3 or 5YR 5/3. Moist color is 7.5YR 3/3, 4/2, 5YR 3/2 or 3/3. Texture is loam, gravelly loam, cobbly loam, gravelly clay loam, cobbly clay loam or very gravelly sandy clay loam. Clay content ranges from 22 to 35 percent. Rock fragments range from 10 to 30 percent gravel and 0 to 15 percent cobbles. Reaction ranges from slightly acid to neutral.
The lower Bt horizon dry color is 7.5YR 4/3, 4/4, 5/3, 5/4, 6/3, 6/4, or 5YR 5/3. Moist color is 7.5YR 3/2, 4/2, 4/3, 4/4, 5YR 3/2, 3/3, or 4/3. Texture is gravelly clay loam, very gravelly clay loam, very cobbly clay loam, extremely cobbly clay loam, very gravelly sandy clay loam, extremely gravelly sandy clay loam, very gravelly sandy clay or very gravelly clay. Clay content ranges from 30 to 45 percent. Rock fragments range from 10 to 70 percent gravel, 5 to 60 percent cobbles and 0 to 5 percent stones. Reaction ranges from neutral to moderately alkaline.
The Btq horizon dry color is 7.5YR 5/4 or 10YR 6/4. Moist color is 7.5YR 4/3, 5/4 or 5YR 3/4. Texture is extremely gravelly sandy clay loam, extremely gravelly sandy clay, extremely cobbly sandy clay loam or extremely cobbly sandy clay. Clay content ranges from 20 to 40 percent. Rock fragments range from 35 to 70 percent gravel, 30 to 60 percent cobbles and 0 to 5 percent stones. Reaction ranges from neutral to moderately alkaline.
COMPETING SERIES: There are no other series in this family.
GEOGRAPHIC SETTING: Wafap soils are on bars on low stream terraces. Slopes range from 0 to 2 percent. These soils formed in alluvium weathered from volcanic rocks. Elevation is 155 to 440 feet, (47 to 134 m). Mean annual precipitation is 25 to 28 inches, (635 to 711 mm). The mean annual temperature is 61 to 62 degrees F, (16 to 17 degrees C). Frost free season is 250 to 255 days.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the Redsluff and Hamslough soils. Redsluff soils are very deep and fine-loamy. Hamslough soils are in channels, are smectitic and poorly drained.
DRAINAGE AND PERMEABILITY: Somewhat poorly drained; very high runoff; moderate to moderately slow saturated hydraulic conductivity in the A and upper Bt horizons, moderately slow to slow in the lower Bt and Btq horizons and impermeable in the 2Bqm horizon. The soils are rarely flooded for very brief periods in December through March. A fluctuating water table can occur between the top of the duripan and 13 inches below the surface of the soil from December through April.
USE AND VEGETATION: This soil is used for livestock grazing, wildlife habitat and watershed. Vegetation is filaree, soft chess, clover, medusahead, wild oat, butter-n-eggs, red brome, brodiaea, bluedicks, goldfields and tidytips.
DISTRIBUTION AND EXTENT: Butte County, California and occur in 262Ab (Northern Eastside Terraces) subsection of the 262A (Great Valley) section. MLRA 17 - Sacramento Valley. The soils are not extensive.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Davis, California
SERIES ESTABLISHED: Butte County, California 2005. Source of name is coined.
REMARKS: Diagnostic horizons and features recognized in this pedon are:
Mollic epipedon - zone from 0 to 13 in, (0 to 33 cm) (A, Bt, Bt2)
Argillic horizon - zone from 1 to 46 in, (3 to 117 cm) (Bt, Bt2, Bt3, Bt4, Btq).
Duripan - 46 in, (117 cm)
Particle-size control section - zone from 1 to 21 in, (3 to 53 cm)
The soil moisture control section - zone from 8 to 46 inches, (20 to 117 cm) is dry in all parts from about June to October (about 140 days).