LOCATION MAC CAEstablished Series
TAXONOMIC CLASS: Fine-loamy, mixed, active, mesic Typic Haploxerults
TYPICAL PEDON: Mac gravelly loam, on a south southwest facing 15 percent slope under a cover of ponderosa pine, white fir, sugar pine, Douglas-fir, incense cedar and tanoak at an elevation of 3540 feet, (1079 m). When described on 7/15/99 the soil was dry throughout. (Colors are for dry soil unless otherwise noted).
Oi--0 to 1 inches, (0 to 3 cm); slightly decomposed plant material; abrupt smooth boundary.
A--1 to 4 inches, (3 to 10 cm); light brown (7.5YR 6/4) gravelly loam, brown (7.5YR 4/4) moist; 23 percent clay; moderate fine and medium granular structure; soft, very friable, slightly sticky, slightly plastic; many very fine, fine and few medium roots; many very fine, fine and medium irregular and tubular pores; 15 percent gravel; moderately acid, pH 6.0 by Hellige-Truog; clear smooth boundary. (2 to 5 inches, (5 to 13 cm) thick)
Bt1--4 to 9 inches, (10 to 22 cm); reddish yellow (5YR 7/6) very gravelly loam, yellowish red (5YR 5/6) moist; 27 percent clay; moderate fine and medium subangular blocky structure; slightly hard, friable, slightly sticky, slightly plastic; common fine, medium few coarse, and many very fine roots; many very fine, fine, medium and coarse irregular and tubular pores; 80 percent continuous faint clay films; 15 percent cobbles and 25 percent gravel; strongly acid, pH 5.5 by Hellige-Truog; clear smooth boundary.
Bt2--9 to 15 inches, (22 to 38 cm); reddish yellow (5YR 6/6) gravelly silty clay loam, yellowish red (5YR 5/6) moist; 29 percent clay; moderate fine and medium subangular blocky structure; slightly hard, friable, slightly sticky, moderately plastic; common very fine, fine, medium and few coarse roots; many very fine, fine, medium and coarse tubular pores; 80 percent continuous distinct clay films; 25 percent gravel; strongly acid, pH 5.4 by Hellige-Truog; gradual smooth boundary.
Bt3--15 to 23 inches, (38 to 58 cm); reddish yellow (5YR 6/6) silty clay loam, yellowish red (5YR 5/6) moist; 31 percent clay; moderate fine and medium subangular blocky structure; slightly hard, very friable, slightly sticky, moderately plastic; common very fine, fine, medium and coarse roots; many very fine, fine and common medium tubular pores; 80 percent continuous distinct clay films; 10 percent gravel; strongly acid, pH 5.3 by Hellige-Truog; clear smooth boundary. (Combined thickness of the Bt horizon is 8 to 38 inches, (20 to 97 cm) thick)
Crt--23 to 37 inches, (58 to 94 cm); pale brown (10YR 6/3) very gravelly silt loam, brown (10YR 5/3) moist; 27 percent clay; massive; soft, very friable, slightly sticky, slightly plastic; few very fine, fine and common medium roots; few very fine, fine and medium tubular pores; 20 percent continuous distinct clay films; 60 percent gravel; very strongly acid, pH 5.0 by Hellige-Truog; clear smooth boundary. (0 to 22 inches, (0 to 56 cm) thick)
Cr--37 inches, (94 cm); weakly cemented phyllite bedrock.
TYPE LOCATION: Butte County, California, about 2.9 miles northeast of Sawmill Peak, approximately 2000 feet north and 2000 feet west of the southeast corner of Section 22, Township 23 N., Range 4 E., 39 degrees, 50 minutes, 8 seconds North latitude and 121 degrees, 30 minutes, 45 seconds West longitude, NAD83 - U.S.G.S. Quad: Paradise East, California.
RANGE IN CHARACTERISTICS: Depth to paralithic bedrock is 20 to 40 inches, (51 to 102 cm). The mean annual soil temperature is 50 to 57 degrees F, (10 to 14 degrees C). The particle-size control section averages 18 to 35 percent clay and 15 to 35 percent rock fragments, mostly gravel. Mineralogy is mixed. Rock fragments on the surface range from 5 to 50 percent gravel, 0 to 10 percent cobbles and 0 to 5 percent stones.
The A horizon dry color is 7.5YR 5/4, 6/4, 6/6, 10YR 6/2, 6/3, 6/4, 7/2, 7/3 or 7/4. Moist color is 7.5YR 4/4, 5YR 4/4, 4/6, 10YR 3/2, 4/2, 4/3, 4/4 or 5/4. Texture is gravelly loam, very gravelly loam or very gravelly sandy loam. Clay content ranges from 15 to 25 percent. Rock fragments range from 15 to 45 percent gravel and 0 to 10 percent cobbles. Reaction ranges from moderately acid to neutral.
The Bt horizon dry color is 5YR 5/6, 6/6, 7/6, 7.5YR 5/6, 6/6, 7/6, 7/3, 10YR 6/4, 7/4, 7/2, 7/3 or 8/6. Moist color is 5YR 4/4, 4/6, 5/6, 5/8, 7.5YR 4/3, 4/4, 5/4, 5/6, 6/6, 10YR 4/2, 4/3, 5/3, 6/6 or 2.5YR 4/6. Texture is gravelly loam, very gravelly loam, clay loam, gravelly clay loam, silt loam, silty clay loam, gravelly silty clay loam or gravelly sandy loam. Clay content ranges from 17 to 35 percent. Rock fragments range from 10 to 45 percent gravel and 0 to 15 percent cobbles. Reaction ranges from strongly acid to slightly acid.
The Crt horizon dry color is 10YR 6/3, 6/4, 7/3 or 2.5Y 6/2. Moist color is 10YR 5/3 or 2.5Y 4/2. Texture is very gravelly silt loam, extremely gravelly loam, extremely gravelly sandy clay loam or extremely cobbly loam. Clay content ranges from 16 to 27 percent. Rock fragments range from 30 to 80 percent gravel and 0 to 40 percent cobbles. Reaction ranges from very strongly acid to slightly acid.
COMPETING SERIES: These are the Jocal and Hietanen series. Jocal soils are very deep. Hietanen soils are deep.
GEOGRAPHIC SETTING: Mac soils are on ridge tops and side slopes on metamorphic Sierra Nevada mountains. Slopes range from 3 to 70 percent. These soils formed in residuum and colluvium weathered from metasedimentary and metavolcanic rocks. Elevation is 2000 to 4000 feet, (610 to 1219 m). Mean annual precipitation is 65 to 73 inches, (1651 to 1854 mm). The mean annual temperature is 52 to 55 degrees F, (11 to 13 degrees C). Frost free season is 140 to 200 days.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the Hietanen, Spine and Dixmine soils. Hietanen and Dixmine soils are deep. Spine soils are shallow.
DRAINAGE AND PERMEABILITY: Well drained; high runoff; moderate to moderately rapid saturated hydraulic conductivity in the A horizon, moderately slow to moderately rapid in the Bt horizon and moderate to moderately slow in the Crt horizon.
USE AND VEGETATION: This soil is used for timber production, wildlife habitat and watershed. Vegetation is ponderosa pine, Douglas-fir, white fir, tanoak, incense cedar, sugar pine, California black oak, canyon live oak, bigleaf maple, whiteleaf manzanita, California honeysuckle and Pacific poison oak.
DISTRIBUTION AND EXTENT: Butte County, California and occurs in the (M261EF) Metamorphic Foothills subsection of the (M261E) Sierra Nevada section. MLRA 22A - Sierra Nevada Range. 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:
Ochric epipedon - zone from 1 to 4 inches, (3 to 10 cm). (A)
Argillic horizon - zone from 9 to 23 inches, (22 to 58 cm). (Bt2, Bt3)
Paralithic Contact - 37 inches, (94 cm)
Particle-size control section zone from 9 to 23 inches, (22 to 58 cm)
The soil moisture control section zone from 9 to 20 inches, (22 to 51 cm) is dry in all parts from about mid June to mid October (about 120 days).
Assumed that base saturation by sum of cations is less than 35 percent at a depth of 37 inches, (94 cm).