LOCATION DONPEDRO                CA

Established Series
MJE/AGB/TKK/JW
09/2018

DONPEDRO SERIES

The Donpedro series consists of moderately deep, well drained soils formed in residuum weathered from slate. The Donpedro soils are on low hills. Slopes range from 3 to 60 percent. The mean annual precipitation is about 570 mm and the mean annual air temperature is about 16 degrees C.

TAXONOMIC CLASS: Fine-loamy, mixed, superactive, thermic Ultic Haploxeralfs

TYPICAL PEDON: Donpedro channery sandy loam on a west-facing, concave, 15 percent slope, under cover of blue oak and annual grasses, at an elevation of 315 meters. (Colors are for dry soils unless otherwise noted. When described on June 14th, 2007 the soil was dry throughout).

A--0 to 5 cm; pale brown (10YR 6/3) channery sandy loam, brown (10YR 4/3) moist; moderate coarse granular structure; slightly hard, friable, nonsticky, nonplastic; common very fine and fine roots throughout; common very fine and fine irregular pores; 10 percent subangular indurated slate channers, 5 percent indurated slate gravel; moderately acid (pH 5.8); abrupt wavy boundary.

AB--5 to 26 cm; pale brown (10YR 6/3) very flaggy sandy loam, brown (10YR 4/3) moist; weak medium subangular blocky structure; slightly hard, rigid, nonsticky, nonplastic; common very fine and fine roots around rock fragments; common very fine and fine irregular pores, few fine tubular and medium irregular pores; 15 percent angular indurated slate gravel, 30 percent angular indurated slate flagstones; strongly acid (pH 5.4); abrupt wavy boundary. (Combined thickness of A horizons is 5 to 30 cm thick)

Bt1--26 to 48 cm; brown (10YR 5/3) sandy loam, brown (10YR 4/3) moist; weak medium subangular blocky structure; moderately hard, firm, nonsticky, nonplastic; common very fine and fine and few medium roots throughout; common very fine and fine irregular, few fine tubular and medium irregular pores; 15 percent faint clay films and 20 percent faint silt coats on all faces of peds; 10 percent angular indurated slate channers; strongly acid (pH 5.5); gradual smooth boundary.

Bt2--48 to 66 cm; brown (10YR 5/3) sandy clay loam, brown (10YR 4/3) moist; weak medium subangular blocky structure; moderately hard, very friable, nonsticky, slightly plastic; few fine and medium roots throughout; many very fine and common fine irregular pores; 15 percent faint clay films and 20 percent faint silt coats on all faces of peds; 5 percent angular indurated slate channers; strongly acid (pH 5.2); abrupt wavy boundary. (Combined thickness of Bt horizons is 20 to 50 cm)

R--66 cm to 200 cm; strongly cemented vertically aligned slate bedrock with fractures more than 10 cm (4 in) apart; very few fine roots in fractures.

TYPE LOCATION: Tuolumne County, California, approximately 3.2 km (2 mi) east-southeast of Hetch Hetchy Junction; USGS 7.5 minute topographic quadrangle: Chinese Camp, California; WGS84 37.791668 latitude and -120.452774 longitude; UTM Zone 10 724280 meters E 4185758 meters N NAD83.

RANGE IN CHARACTERISTICS:

Soil temperature: The mean annual soil temperature at 50 cm is 16 to 17 degrees C and the difference between mean summer and mean winter soil temperature is greater than 6 degrees C. The soils have a thermic temperature regime.

Soil moisture: The soil moisture control section is dry in all parts from about May to October. The soils have a xeric moisture regime.

Diagnostic Feature(s)
Ochric epipedon thickness: 5 to 30 cm
Argillic horizon thickness: 20 to 60 cm
Depth to lithic contact: 50 to 100 cm

Base saturation (by sum of cations): less than 75 percent in one or more subhorizons within the upper 75 cm of the argillic horizon or above the lithic contact (whichever is shallower)

Particle size control section weighted-average:
Rock fragments: 0 to 20 percent; with 0 to 10 percent gravel, and 0 to 20 percent channers
Clay content: 18 to 35 percent

A horizon(s):
Hue: 7.5YR, 10YR
Value: 4 to7 dry; 3 or 4 moist
Chroma: 2 to 4 dry; 2 to 4 moist
Textures: sandy loam, loam
Clay content: 5 to 18 percent
Rock fragments: 0 to 45 percent;
0 to 15 percent gravels
0 to 20 percent channers
0 to 30 percent flagstones
Reaction: slightly acid to neutral

Bt1 horizon(s):
Hue: 10YR, 7.5YR
Value: 4 to 6 dry; 3 or4 moist
Chroma: 3 or4 dry; 2 to4 moist
Textures: loam, sandy loam, sandy clay loam
Clay content: 15 to 27 percent
Rock fragments: 0 to 20 percent;
0 to 20 percent gravels;
0 to 10 percent channers;
Reaction: very strongly acid to neutral

Bt2 horizon(s):
Hue: 7.5YR, 10YR
Value: 5 or6 dry; 3 to5 moist
Chroma: 3 or4 dry; 3 or4 moist
Textures: loam, sandy clay loam, clay loam
Clay content: 20 to 35 percent
Rock fragments: 0 to 25 percent;
0 to 20 percent gravels
0 to 10 percent channers
Reaction: very strongly acid to neutral

COMPETING SERIES: These are the Bearwallow (MLRA 15), Churn (MLRA 17), Loafercreek, Mounthope, Sommeyflat and Wisheylu series. Bearwallow, Churn, Someyflat and Wisheylu soils are greater than 150cm to a bedrock contact. Loafercreek soils are 50 to 100 cm to a paralithic contact of metavolcanic rock. Mounthope soils are 100 to 150 cm to a paralithic contact of greenschist or intrusive igneous rock.

GEOGRAPHIC SETTING: The Donpedro soils are on side slopes of low hills. Slopes range from 3 to 60 percent. These soils formed in residuum weathered from slate or other metasedimentary rocks. Elevation is 150 to 500 meters. The climate is Mediterranean with warm, dry summers and cool, moist winters. The mean annual precipitation is 400 to 800 mm and the mean annual air temperature is 16 to 17 degrees C. The frost free season is 260 to 345 days.

GEOGRAPHICALLY ASSOCIATED SOILS: These are the Whiterock, Copperopolis and Moccasinhill series. Whiterock soils occur on nose slopes of low hills and are less than 50cm to a lithic contact. Copperopolis soils are on crests and side slopes of low hills, have greater than 35 percent rock fragments in the particle-size control section and are less than 50 cm to lithic contact. Moccasinhill soils occur on side slopes and nose slopes of hills, have greater than 35 percent rock fragments in the particle-size control section, and are 50 to 100cm to a lithic contact. All lack an argillic horizon.

DRAINAGE AND PERMEABILITY: Well drained; moderately high to high saturated hydraulic conductivity. Saturated hydraulic conductivity of the bedrock is low to very high

USE AND VEGETATION: This soil is used for wildlife habitat, watershed, recreation and homesite development. Vegetation is blue oak and annual grasses.

DISTRIBUTION AND EXTENT: Sierra Nevada Foothills of California; MLRA 18. The series is not extensive.

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

SERIES PROPOSED: Tuolumne County, California. Source of name is Don Pedro Reservoir.

REMARKS:
Diagnostic horizons and features recognized in this pedon are:
Ochric epipedon 0 to 26 cm
Argillic horizon 26 to 66 cm
Lithic contact 66 to 200 cm

Particle Size Control Section for this pedon: 26 to 66 cm.

ADDITIONAL DATA:
Pedon information for this type location only:
NASIS User Pedon ID: 07SKC007
Pedon Type: OSD Pedon

No certified laboratory data exist for this soil.

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

---

National Cooperative Soil Survey
U.S.A.