LOCATION COLONYMILL CA

Established Series
JBB/CES/JTW
09/2021

COLONYMILL SERIES

The Colonymill series consists of very deep, well drained soils formed in colluvium and residuum derived from schist and other metasedimentary rocks. The Colonymill soils are on mountain slopes of the Sierra Nevada Mountains. Slopes range from 15 to 100 percent. The mean annual precipitation is about 945 mm and the mean annual air temperature is about 11 degrees C.

TAXONOMIC CLASS: Fine-loamy, isotic, mesic Pachic Ultic Argixerolls

TYPICAL PEDON: Colonymill loam on a southwest-facing (220 degree), 60 percent slope under a cover of live oak and manzanita at an elevation of 1518 meters. (Colors are for dry soils unless otherwise noted. When described on April 16, 2014 the soil was moist throughout.)

Oi--0 to 2 cm; brown (7.5YR 4/2) slightly decomposed plant material, very dark brown (7.5YR 2/2) moist; slightly acid (pH 6.4); very abrupt wavy boundary. (2 to 8 cm thick)

A--2 to 9 cm; brown (7.5YR 4/2) loam, very dark brown (7.5YR 2/2) moist; 10 percent clay; moderate fine granular structure; soft, very friable, slightly sticky, nonplastic; common very fine and fine roots throughout; many very fine irregular pores; 1 percent subangular indurated schist channers; NaF pH 9.0; slightly acid (pH 6.4); abrupt wavy boundary. (7 to 25 cm thick)

BA--9 to 20 cm; brown (7.5YR 4/3) loam, dark reddish brown (5YR 2.5/2) moist; 20 percent clay; weak medium subangular blocky parts to moderate fine granular structure; slightly hard, friable, slightly sticky, nonplastic; common very fine, fine, and coarse roots throughout; many very fine irregular and common fine tubular pores; 5 percent subangular indurated schist channers; NaF pH 9.0; slightly acid (pH 6.4); clear smooth boundary. (10 to 40 cm thick)

Bw--20 to 55 cm; brown (7.5YR 4/3) loam, dark reddish brown (5YR 2.5/2) moist; 26 percent clay; moderate medium subangular blocky structure; slightly hard, friable, slightly sticky, slightly plastic; common very fine, fine, medium, and coarse roots throughout; common very fine irregular and common fine tubular pores; 5 percent angular indurated schist channers, 5 percent subangular indurated schist gravel, 1 percent subangular indurated schist cobbles; NaF pH 9.0; moderately acid (pH 6.0); gradual smooth boundary. (10 to 40 cm thick)

Bt1--55 to 98 cm; brown (7.5YR 4/3) clay loam, dark reddish brown (5YR 3/2) moist; 29 percent clay; moderate coarse subangular blocky structure; slightly hard, friable, moderately sticky, slightly plastic; common very fine, fine, medium, and very coarse roots throughout; common very fine irregular and common fine and medium tubular pores; 5 percent faint clay films on surfaces along pores; 15 percent coarse dark reddish brown (2.5YR 3/4) masses of oxidized iron; 7 percent subangular indurated schist gravel, 7 percent subangular indurated schist cobbles; NaF pH 9.0; moderately acid (pH 5.8); clear wavy boundary. (20 to 45 cm thick)

Bt2--98 to 129 cm; brown (7.5YR 5/4) cobbly clay loam, reddish brown (5YR 4/3) moist; 37 percent clay; moderate medium subangular blocky structure; moderately hard, firm, slightly sticky, moderately plastic; common medium, coarse, and very coarse roots throughout; common very fine irregular and common fine and medium tubular pores; 5 percent faint clay films on surfaces along pores and 10 percent faint clay films on all faces of peds; 10 percent subangular strongly cemented schist gravel, 5 percent subangular very weakly cemented schist paragravel, 15 percent subangular strongly cemented schist cobbles; NaF pH 9.0; moderately acid (pH 5.8); gradual wavy boundary.

Bt3--129 to 160 cm; brown (7.5YR 5/4) very cobbly clay loam, reddish brown (5YR 4/3) moist; 33 percent clay; moderate medium subangular blocky structure; moderately hard, firm, slightly sticky, moderately plastic; few fine and medium roots throughout and common very coarse roots top of horizon; common fine and medium tubular pores; 5 percent faint clay films on surfaces along pores and 10 percent faint clay films on all faces of peds; 10 percent subangular strongly cemented schist gravel, 25 percent subangular strongly cemented schist cobbles, 10 percent subangular strongly cemented schist stones; NaF pH 9.0; moderately acid (pH 5.8). (combined thickness of the lower Bt horizons is 30 to 100 cm)

TYPE LOCATION: Tulare County, California, near Crystal Cave parking area in Sequoia National Park; USGS 7.5 minute topographic quadrangle: Giant Forest, California; WGS84 36.585556 latitude and -118.826483 longitude; UTM zone 11 4050452 meters N 336601 meters E NAD83.

RANGE IN CHARACTERISTICS:
Soil temperature: The mean annual soil temperature at 50 cm is 11 to 15 degrees C and the difference between mean summer and mean winter soil temperature is greater than 6 degrees C. The soils have a mesic temperature regime.

Soil moisture: The soils have a xeric soil moisture regime. The soil moisture control section is dry in all parts from about July to October (about 120 days).

Diagnostic Feature(s):
Mollic epipedon thickness: 50 to 75 cm
Argillic horizon thickness: 70 to greater than 150 cm

Organic matter: 1 to 5 percent in the epipedon

Base saturation: greater than 50 percent in the epipedon (by ammonium acetate) and 35 to 75 percent in one or more horizons between 25 and 75 cm from the mineral soil surface (by sum of cations).

Particle size control section weighted average:
Rock fragments: 0 to 35 percent, with 0 to 35 percent gravel and 0 to 5 percent cobbles.
Clay content: 18 to 32 percent
NaF pH: 8.5 to 10.0

A horizon
Hue: 7.5YR, 10YR
Value: 4 dry, 2 or 3 moist
Chroma: 3 or 4 dry, 2 or 3 moist
Texture: loam, sandy loam
Clay content: 10 to 22 percent
Rock fragments: 0 to 15 percent
0 to 15 percent gravel or channers
0 to 5 percent cobbles
Reaction: strongly acid to neutral

BA, ABt or Bw horizons (where present)
Hue: 5YR, 7.5YR
Value: 4 or 5 dry, 2 or 3 moist
Chroma: 3 or 4 dry, 2 or 3 moist
Texture: loam, sandy loam, clay loam
Clay content: 15 to 30 percent
Rock fragments: 0 to 25 percent
0 to 15 percent gravel or channers
0 to 10 percent cobbles
Reaction: strongly acid to neutral

Bt1 horizon
Hue: 5YR, 7.5YR
Value: 4 5 dry, 3 or 4 moist
Chroma: 3 or 4, dry or moist
Texture: loam, clay loam
Clay content: 18 to 35 percent
Rock fragments: 0 to 35 percent
0 to 30 percent gravel
0 to 15 percent cobbles
Reaction: moderately acid to slightly acid

Lower Bt horizons (Bt2, Bt3)
Hue: 5YR, 7.5YR
Value: 5 dry, 3 or 4 moist
Chroma: 4 or 6 dry, 3 or 4 moist
Texture: clay loam, loam
Clay content: 22 to 40 percent
Rock fragments: 0 to 60 percent
0 to 35 percent gravel
0 to 25 percent cobbles
0 to 15 percent stones
Reaction: strongly acid to slightly acid

COMPETING SERIES: There are no other series in this family at this time.

GEOGRAPHIC SETTING: The Colonymill soils are on backslopes of mountain slopes. Slopes range from 15 to 100 percent. These soils formed in colluvium and residuum derived from schist. Elevation is 755 to 2020 meters. The climate is Mediterranean with warm, dry summers and cool, moist winters. The mean annual precipitation is 730 to 1030 mm and the mean annual air temperature is 10 to 15 degrees C. The frost free season is 160 to 245 days.

GEOGRAPHICALLY ASSOCIATED SOILS: These are the Kaweah, Ladybug, and Whiskeylog soils. The Kaweah soils are on concave to linear drainages on mountain slopes and have greater than 35 percent rock fragments in the particle size control section. The Ladybug soils are on shoulders of mountain slopes and are 100 to 150 cm to a lithic contact. The Whiskeylog soils are on convex mountain slopes and lack a mollic epipedon (dark surface).

DRAINAGE AND PERMEABILITY: Well drained, moderately high saturated hydraulic conductivity.

USE AND VEGETATION: This soil is used for recreation, wildlife habitat, and watershed. Vegetation includes canyon live oak, black oak, whiteleaf manzanita, alderleaf mountain mahogany, and poison oak.

DISTRIBUTION AND EXTENT: Sierra Nevada Mountains of California; MLRA 22A. These soils are of limited extent.

SOIL SURVEY REGIONAL OFFICE (SSRO) RESPONSIBLE: Davis, California

SERIES PROPOSED: Tulare County, California, in Sequoia and Kings Canyon National Parks. Source of name from the old Colony Mill Road, hand built by the utopian Kaweah colonists between 1886 and 1890, near the type location in Sequoia National Park.

REMARKS:
Particle Size Control Section for this pedon: 55 to 105 cm
Diagnostic horizons and features recognized in this pedon are:
Mollic Epipedon 2 to 55 cm
Argillic Horizon 55 to 160 cm

ADDITIONAL DATA:
NASIS User Pedon ID: 2014CA7925017

Soil classified using the 12th Edition of the Keys to Soil Taxonomy.

NASIS User Pedon IDs with supporting data in Sequoia National Park: 1983CA107011.

National Cooperative Soil Survey
U.S.A.