LOCATION MILLVILLA CA

Established Series
SMM/CES/TKK/JW
11/2018

MILLVILLA SERIES

The Millvilla series consists of moderately deep, well drained soils that formed in colluvium over residuum weathered from phyllite, schist, and other metasedimentary rocks. The Millvilla soils are on hills and in canyons. Slopes range from 3 to 90 percent. The mean annual precipitation is about 810 millimeters and the mean annual air temperature is about 15 degrees C.

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

TYPICAL PEDON: Millvilla silt loam on an east-facing, 45 percent, convex slope under interior live oak, foothill pine, and yerba santa at an elevation of 500 meters. (Colors are for dry soils unless otherwise noted. When described on May 7, 2007 the soil was moist throughout.)

Oi--0 to 1 cm; slightly decomposed grass, leaves, and twigs; abrupt broken boundary. (0 to 2 cm thick)

A--1 to 5 cm; brown (7.5YR 5/3) silt loam, dark brown (7.5YR 3/3) moist; weak fine subangular blocky structure; slightly hard, friable, slightly sticky, slightly plastic; many very fine and common fine roots throughout; common very fine and fine irregular pores; 2 percent indurated quartzite gravel and 3 percent very strongly cemented schist gravel; neutral, pH 7.0; clear wavy boundary. (3 to 13 cm thick)

BA--5 to 23 cm; brown (7.5YR 5/4) loam, dark brown (7.5YR 3/4) moist; weak medium subangular blocky structure; slightly hard, friable, slightly sticky, slightly plastic; common very fine and fine roots throughout; common very fine and fine irregular pores; 2 percent indurated quartzite gravel, 3 percent very strongly cemented schist gravel, 2 percent moderately cemented schist paragravel, 2 percent indurated quartzite cobbles, and 3 percent very strongly cemented schist cobbles; neutral, pH 7.2; gradual wavy boundary. (0 to 18 cm thick)

Bt1--23 to 56 cm; brown (7.5YR 5/4) loam, reddish brown (5YR 4/4) moist;; moderate medium subangular blocky structure; hard, firm, moderately sticky, moderately plastic; few very fine and fine roots throughout; common very fine and fine irregular and few fine tubular pores; 15 percent distinct yellowish red (5YR 5/6) clay films on all faces of peds and on surfaces along pores; 2 percent very strongly cemented schist gravel and 5 percent moderately cemented schist paragravel and 5 percent indurated quartz gravel; neutral, pH 6.8; clear wavy boundary. (5 to 38 cm thick)

Bt2--56 to 82 cm; brown (7.5YR 5/4) gravelly loam, brown (7.5YR 4/4) moist;; weak coarse subangular blocky structure; hard, firm, moderately sticky, moderately plastic; few very fine roots throughout; few very fine and fine irregular and few fine and medium tubular pores; 20 percent faint strong brown (7.5YR 4/6) clay films on all faces of peds; 2 percent fine mica flakes; 10 percent indurated quartz gravel, 5 percent very strongly cemented schist cobbles, 10 percent moderately cemented schist paragravel, and 2 percent moderately cemented schist paracobbles; slightly acid, pH 6.5; clear irregular boundary. (10 to 30 cm thick)

Crt--82 to 102 cm; Moderately cemented mica schist bedrock interbedded with indurated quartzite veins; 10 percent fine mica flakes; fractures are more than 10 centimeters apart with clay coatings on rock faces between fractures. (18 to 38 cm thick)

R--102 cm; Indurated schist and quartzite bedrock.

TYPE LOCATION: Tuolumne County, California, about 2.8 km (1.7 miles) southwest of Sonora, CA, USGS 7.5 minute topographic quadrangle: Sonora, California; WGS84 37.960835 latitude and -120.401665 longitude, UTM Zone 10 728256 meters E 4204639 meters N NAD83.

RANGE IN CHARACTERISTICS:
Soil temperature: The mean annual soil temperature at 50 cm is 15 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 (about 180 days). The soils have a xeric soil moisture regime.

Diagnostic Feature(s):
Ochric epipedon thickness: 4 to 25 cm
Argillic horizon thickness: 40 to 85 cm
Depth to paralithic contact: 50 to 100 cm

Particle size control section weighted average:
Rock fragments: 2 to 30 percent gravel, 4 to 45 percent paragravel
Clay content: averages 18 to 27 percent clay
Silt content: dominated by fine silt fraction

Base saturation: less than 75 percent in one or more subhorizons of the argillic horizon (by sum of cations)

A horizon
Hue: 7.5YR, 10YR
Value: 4 to 6 dry, 3 or 4 moist
Chroma: 2 to 6 dry, 2 to 4 moist
Texture: silt loam, loam, fine sandy loam
Clay content: 12 to 20 percent
Rock fragments: 0 to 15 percent
0 to 15 percent gravel
Pararock fragments: 0 to 5 percent paragravel
Reaction: moderately acid to neutral

BA horizon (when present)
Hue: 7.5YR, 10YR
Value: 5 to 7 dry, 2 to 4 moist
Chroma: 2 to 6 dry; 3 or 4 moist
Texture: silt loam, loam, fine sandy loam
Clay content: 14 to 25 percent
Rock fragments: 0 to 20 percent
0 to 15 percent gravel
0 to 5 percent cobbles
0 to 5 percent channers
Pararock fragments: 0 to 5 percent paragravel
Reaction: moderately acid to neutral

Bt horizon(s), upper part
Hue: 5YR, 7.5YR, 10YR
Value: 4 to 6 dry, 3 to 5 moist
Chroma: 4 or 6, dry or moist
Texture: loam, silt loam, clay loam
Clay content: 18 to 27 percent
Rock fragments: 0 to 30 percent
0 to 30 percent gravel
0 to 10 percent cobbles
0 to 10 percent channers
Pararock fragments: 0 to 10percent
0 to 10 percent paragravel
0 to 5 percent paracobbles
Reaction: strongly acid to slightly acid

Bt horizon(s), lower part
Hue: 5YR, 7.5YR, 10YR
Value: 4 to 6 dry, 3 to 5 moist
Chroma: 4 or 6, dry or moist
Texture: clay loam, loam, silt loam, silty clay loam
Clay content: 20 to 35 percent
Rock fragments: 0 to 35 percent
0 to 35 percent gravel
0 to 30 percent cobbles
0 to 5 percent stones
0 to 10 percent channers
Pararock fragments: 0 to 35 percent
0 to 35 percent paragravel
0 to 15 percent paracobbles
Reaction: strongly acid to slightly acid

COMPETING SERIES: These are the Coombs (MLRA 15), Craigsaddle, Flanly, Motherlode, Sierra, Thompsonflat (MLRA 17), Verjeles, Wardsferry and Yellowlark (MLRA 17) soils. Coombs, Craigsaddle, Motherlode, Sierra, Thompsonflat, Wardsferry, and Yellowlark soils are more than 100 cm to bedrock. Flanly soils are formed in granodiorite and have sandy loam and sandy clay loam textures in the Bt horizons. Verjeles soils are formed in gabbrodiorite and have 2Bt horizons with clay content ranging from 40 to 60 percent.

GEOGRAPHIC SETTING: The Millvilla soils are on linear side slopes and convex nose slopes of hills and on concave footslopes in canyons. Slopes range from 3 to 90 percent. These soils formed in colluvium over residuum weathered from phyllite, and schist, and other metasedimentary rocks. Elevation is 225 to 885 meters. The climate is Mediterranean with warm, dry summers and cool, moist winters. The mean annual precipitation is 670 to 1000 millimeters and the mean annual air temperature is 13 to 16 degrees C. The frost free season is 190 to 315 days.

GEOGRAPHICALLY ASSOCIATED SOILS: These are the Aquariusmine, Deerflat, Hetchy, and Sanguinetti soils, and the competing Wardsferry soils. The Aquariusmine soils are 100 to 150 cm to indurated marble and are on adjacent linear side slopes. The Deerflat soils are greater than 150 cm to bedrock, and are on adjacent baseslopes. The Hetchy soils are 50 to 100 cm to a lithic contact, are loamy-skeletal, and are on convex side slopes, nose slopes, and interfluves. The Sanguinetti soils are loamy-skeletal and are on adjacent side slopes. The Wardsferry soils are 100 to 150cm to a paralithic contact and are on concave headslopes.

DRAINAGE AND SATURATED HYDRAULIC CONDUCTIVITY: Well drained; moderately high to high saturated hydraulic conductivity throughout the soil profile.

USE AND VEGETATION: This soil is used for watershed, wildlife habitat, recreation, and home site development. Vegetation is interior live oak, blue oak, California foothill pine, Pacific poison oak, whiteleaf manzanita, toyon, buckbrush, chaparral coffeeberry, California yerba santa, and squirreltail.

DISTRIBUTION AND EXTENT: Sierra Nevada Foothills in California; MLRA 18. The series is moderately extensive

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

SERIES PROPOSED: Tuolumne County, California, 2018. Source of name from a hill near the intersection of Highway 108 and Stockton Rd in Sonora, California.

REMARKS:
Diagnostic horizons and features recognized in this pedon are:
Ochric Epipedon 1 to 23 cm
Argillic Horizon 23 to 82 cm
Paralithic Contact 82 to 102 cm
Lithic Contact 102 cm
Particle Size Control Section for this pedon: 23 to 73 cm.

ADDITIONAL DATA:
NASIS Pedon ID: 07SMM006
No certified laboratory data exist for this soil.

National Cooperative Soil Survey
U.S.A.