LOCATION MOUNTBALDY CA

Established Series
REV: JTB/JWH/ET/SA
10/2016

MOUNTBALDY SERIES

The Mountbaldy series consists of moderately deep, well drained soils formed in residuum derived from sandstone. Mountbaldy soils are on mountains and slopes range from 15 to 75 percent. The mean annual precipitation is about 1520 mm and the mean annual air temperature is about 11 degrees C.

TAXONOMIC CLASS: Loamy-skeletal, mixed, superactive, isomesic Ultic Haplustalfs

TYPICAL PEDON: Mountbaldy very gravelly loam on a northwest facing slope of 10 percent under a logged forest of Douglas-fir and tanoak. (Colors are for dry soil unless otherwise stated. When described on September 18, 2003, the soil was dry throughout).

Oi--0 to 4 centimeters; very dark grayish brown (10YR 3/2) slightly decomposed plant material, very dark gray (10YR 3/1) moist; very dark brown (7.5YR 2.5/2) rubbed; 90 percent fibers, 50 percent rubbed; moderately acid (pH 6.0); abrupt wavy boundary. (0 to 10 centimeters thick)

A--4 to 11 centimeters; brown (10YR 5/3) very gravelly loam, very dark grayish brown (10YR 3/2) moist; moderate very fine granular structure; soft, very friable, nonsticky and nonplastic; many fine, very fine, and common medium and coarse roots throughout; many very fine tubular pores; 60 percent gravel; strongly acid (pH 5.4); clear smooth boundary. (5 to 25 centimeters thick)

ABt--11 to 21 centimeters; pale brown (10YR 6/3) very gravelly loam, dark brown (10YR 3/3) moist; moderate fine subangular blocky structure; soft, very friable, slightly sticky and slightly plastic; many fine, very fine, and common medium and coarse roots throughout; many very fine and common coarse tubular pores; few distinct very dark grayish brown (10YR 3/2) moist organoargillans on all faces of peds; 50 percent gravel; strongly acid (pH 5.4); clear wavy boundary. (0 to 20 centimeters thick)

Bt1--21 to 30 centimeters; light yellowish brown (10YR 6/4) very gravelly loam, dark yellowish brown (10YR 4/4) moist; strong fine subangular blocky structure; slightly hard, very friable, slightly sticky and slightly plastic; common fine, very fine, medium, and coarse roots throughout; common fine tubular pores; common distinct dark grayish brown (10YR 4/2) moist clay films on all faces of peds; 30 percent gravel and 10 percent cobbles; strongly acid (pH 5.4); clear wavy boundary.

Bt2--30 to 56 centimeters; dark yellowish brown (10YR 4/4) very gravelly loam, yellowish brown (10YR 5/6) moist; strong fine and medium subangular blocky structure; slightly hard, very friable, slightly sticky and slightly plastic; common fine, medium, and coarse roots throughout; common fine tubular pores; common distinct clay films on all faces of peds; 40 percent gravel and 20 percent cobbles; strongly acid (pH 5.2); abrupt irregular boundary. (Combined thickness of the Bt horizons is 25 to 95 centimeters)

R--56 centimeters; fractured sandstone; fractures 10 to 20 centimeters apart; strongly cemented; few very fine roots in cracks.

TYPE LOCATION: Humboldt County, California; about 9 kilometers southeast of the town of Redcrest; section 16, T.1S, R.3E, HBLM; USGS Bridgeville 7.5 minute topographic quadrangle; WGS84 Decimal degrees 40.383473 latitude, -124.8424285 longitude; UTM 10T 428494e, 4470661n; NAD 83.

RANGE IN CHARACTERISTICS:

Soil Temperature: The mean annual soil temperature at 50 centimeters is 9 to 11 degrees C. (48 to 51 degrees F) and the difference between mean summer and mean winter soil temperatures is less than 6 degrees C. The soils have an isomesic temperature regime.

Soil Moisture: The soil moisture control section is usually dry in some or all parts for 90 or more cumulative days. This soil is dry in the upper part from about July 15 to October 15 in most years. The soils have an ustic soil moisture regime.

Reaction: strongly acid to moderately acid

Particle size control section (weighted average):
Rock fragments: 35 to 75 percent gravel, 0 to 15 percent cobbles and stones
Clay content: 20 to 30 percent

A horizon
Hue: 7.5YR or 10YR
Value: 3 to 5, 2 to 3 moist
Chroma: 1 to 3, dry or moist
Clay content: 10 to 26 percent
Rock fragments: 35 to 59 percent strongly cemented sandstone gravel, 0 to 34 percent cobbles

Bt horizon
Hue: 7.5YR or 10YR
Value: 5 to 6, 3 or 4 moist
Chroma: 2 to 4 dry or moist
Clay content: 15 to 30 percent
Texture of fine earth: sandy loam, loam, sandy clay loam, clay loam
Rock fragments: 35 to 89 percent strongly cemented sandstone gravel, 0 to 34 percent cobbles and 0 to 10 percent stones

COMPETING SERIES: This is the Yellowhound series. Yellowhound soils have a lithic contact between 100 and 150 centimeters.

GEOGRAPHIC SETTING: Mountbaldy soils are on strongly convex positions on ridges and mountain slopes. Slopes are 15 to 75 percent. Elevations are 60 to 1150 meters. These soils formed in residuum from sandstone. The climate is humid with cool, foggy summers and cool, wet winters. Mean annual precipitation is 1140 to 2160 millimeters. Mean annual temperature is 10 to 13 degrees C. Frost free season is about 240 to 300 days.

GEOGRAPHICALLY ASSOCIATED SOILS: These are the Mailridge (T), Redwoodhouse, and Yagercreek soils. Mailridge, Redwoodhouse, and Yagercreek soils lack a lithic contact in the series control section. Redwoodhouse and Yagercreek soils occur on linear to slightly concave or convex positions and Mailridge soils are on linear to convex positions.

DRAINAGE AND SATURATED HYDRAULIC CONDUCTIVITY: Well drained; high runoff; moderately low to moderately high saturated hydraulic conductivity.

USE AND VEGETATION: This soil is used for timber production, wildlife habitat, and watershed. Natural vegetation includes redwood, Douglas-fir, tanoak, Pacific madrone, evergreen huckleberry, salal, and western swordfern.

DISTRIBUTION AND EXTENT: Coastal Redwood Belt; MLRA 4B. The series is not extensive.

MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Davis, California

SERIES ESTABLISHED: Humboldt County Soil Survey, Southern Part, California 2016. Proposed 2014. The name is from Mount Baldy.

REMARKS: Diagnostic horizons and features recognized in this pedon are:

1. Ochric epipedon - the zone from 0 to 11 centimeters (A horizon).
2. Argillic horizon - the zone from 11 to 56 centimeters (ABt, Bt1, Bt2 horizons).3. Ultic subgroup - the argillic horizon has a base saturation by sum of cations of less than 75 percent.
4. Particle-size control section - the zone from 11 to 56 centimeters (ABt, Bt1, Bt2 horizons) averages 22 percent clay and 51 percent rock fragments.
5. Lithic contact at 56 centimeters (top of the R horizon)

ADDITIONAL DATA:

NASIS User Pedon ID: 03CA601223

Keys to Soil Taxonomy, 12th edition

National Cooperative Soil Survey
U.S.A.