LOCATION MOROROCK CA

Established Series
JBB/CES/JTW
09/2021

MOROROCK SERIES

The Mororock series consists of very deep, somewhat excessively drained soils formed in colluvium and residuum derived from granitic and metasedimentary rocks. The Mororock soils are on mountain slopes and canyon walls of the Sierra Nevada Mountains. Slopes range from 10 to 90 percent. The mean annual precipitation is about 895 mm and the mean annual air temperature is about 13 degrees C.

TAXONOMIC CLASS: Coarse-loamy, isotic, mesic Ultic Haploxerolls

TYPICAL PEDON: Mororock gravelly loam on a southwest-facing (225 degree), 80 percent slope under a cover of flannel bush, mountain mahogany, and poison oak at an elevation of 1340 meters. (Colors are for dry soils unless otherwise noted. When described on June 17, 1983 the soil was dry throughout.)

Oe--0 to 3 cm; moderately decomposed plant material. (0 to 5 cm thick)

A--3 to 30 cm; dark brown (10YR 3/3) gravelly loam, very dark gray (10YR 3/1) moist; 42 percent sand; 46 percent silt; 13 percent clay; moderate fine and medium granular structure; slightly hard, very friable, moderately sticky, slightly plastic; few fine, medium, and coarse roots; few very fine and fine tubular pores; 30 percent angular mica schist gravel and cobbles; slightly acid (pH 6.3); abrupt wavy boundary. (5 to 35 cm thick)

AB--30 to 50 cm; brown (10YR 4/3) gravelly loam, dark brown (10YR 3/3) moist; 45 percent sand; 48 percent silt; 13 percent clay; weak medium angular blocky structure; slightly hard, friable, nonsticky, slightly plastic; few very fine and fine roots; common fine tubular pores; 30 percent angular mica schist gravel and cobbles; slightly acid (pH 6.3); abrupt wavy boundary. (10 to 30 cm thick)

Bw--50 to 103 cm; yellowish brown (10YR 5/4) gravelly loam, yellowish brown (10YR 5/6) moist; 49 percent sand; 41 percent silt; 10 percent clay; weak coarse angular blocky structure; hard, friable, slightly sticky, slightly plastic; few very fine, fine, medium, and coarse roots; common fine and few medium tubular pores; 30 percent angular mica schist gravel and cobbles; slightly acid (pH 6.4); clear wavy boundary. (40 to 65 cm thick)

C--103 to 153 cm; brown (10YR 5/3) gravelly loam, yellowish brown (10YR 5/4) moist; structureless massive.

TYPE LOCATION: Tulare County, California, approximately 45 m NW of Amphitheater Point on contour trail; USGS 7.5 minute topographic quadrangle: Giant Forest, California; WGS84 36.538364 latitude and -118.784644 longitude; UTM zone 11 4045146 meters N 340247 meters E NAD83.

RANGE IN CHARACTERISTICS:
Soil temperature: The mean annual soil temperature at 50 cm is 10 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 June to October (about 150 days).

Diagnostic Feature(s):
Mollic epipedon thickness: 20 to 50 cm
Cambic horizon thickness: 40 to 75 cm

Organic matter: 1 to 5 percent in the epipedon

Base saturation: greater than 50 percent (by ammonium acetate) throughout, and 35 to 75 percent between 25 and 75 cm below 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 35 percent cobbles.
Clay content: 5 to 15 percent

A horizon
Hue: 7.5YR, 10YR
Value: 3 or 4 dry, 2 or 3 moist
Chroma: 2 or 3 dry, 1 or 2 moist
Texture: sandy loam, loam
Clay content: 2 to 13 percent
Rock fragments: 0 to 35 percent
0 to 35 percent gravel
0 to 35 percent cobbles
Reaction: slightly acid to neutral

AB or BA horizon
Hue: 7.5YR, 10YR
Value: 4 or 5 dry, 2 or 3 moist
Chroma: 2 or 3, dry or moist
Texture: sandy loam, loam
Clay content: 5 to 13 percent
Rock fragments: 0 to 35 percent
0 to 35 percent gravel
0 to 35 percent cobbles
Reaction: slightly acid

Bw horizon
Hue: 7.5YR, 10YR
Value: 4 or 5 dry, 2 to 5 moist
Chroma: 3 to 6 dry, 2 to 6 moist
Texture: sandy loam, loam
Clay content: 8 to 15 percent
Rock fragments: 0 to 35 percent
0 to 35 percent gravel
0 to 35 percent cobbles
Reaction: slightly acid

C horizon
Hue: 7.5YR, 10YR
Value: 4 to 6 dry, 3 to 5 moist
Chroma: 3 or 4 dry, 2 to 6 moist
Texture: sandy loam, loam, loamy sand
Clay content: 3 to 15 percent
Rock fragments: 0 to 60 percent
0 to 35 percent gravel
0 to 45 percent cobbles
Reaction: moderately to slightly acid

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

GEOGRAPHIC SETTING: The Mororock soils are on steep linear to concave drainages of mountain slopes and canyon walls. Slopes range from 10 to 90 percent. These soils formed in colluvium and residuum derived from metasedimentary or granitic rocks. Elevation is 745 to 2215 meters. The climate is Mediterranean with warm, dry summers and cool, moist winters. The mean annual precipitation is 730 to 1070 mm and the mean annual air temperature is 9 to 16 degrees C. The frost free season is 150 to 255 days.

GEOGRAPHICALLY ASSOCIATED SOILS: These are the Edencreek and Grunigen soils. Edencreek soils are on convex backslopes of mountain slopes, and have a paralithic contact between 50 and 100 cm. The Grunigen soils are on linear to concave drainageways on mountain slopes, have a mollic epipedon, and are 50 cm to a lithic contact.

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

USE AND VEGETATION: This soil is used for recreation, wildlife habitat, and watershed. Vegetation is canyon live oak, alderleaf mountain mahogany, poison oak, flannel bush, and annual grasses and forbs.

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 prominent landform in Sequoia National Park.

REMARKS:
Particle Size Control Section for this pedon: 28 to 103 cm.
Diagnostic horizons and features recognized in this pedon are:
Mollic Epipedon 3 to 50 cm
Cambic Horizon 50 to 103 cm

ADDITIONAL DATA:
NASIS User Pedon ID: 1983CA107011

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

National Cooperative Soil Survey
U.S.A.