LOCATION BAMTUSH CA

Established Series
Rev. DWS/WDB/CEJ/WRR
04/2023

BAMTUSH SERIES

The Bamtush series consists of very deep, well drained soils formed in material weathered from sedimentary and metasedimentary rocks. Bamtush soils are on mountains. Slopes is 15 to 75 percent. The mean annual precipitation is about 50 inches and the mean annual temperature is about 52 degrees F.

TAXONOMIC CLASS: Loamy-skeletal, mixed, superactive, mesic Ultic Palexeralfs

TYPICAL PEDON: Bamtush gravelly loam--on a west facing convex slope of 15 percent under ponderosa pine, Douglas-fir and California black oak at an elevation of 3,600 feet. (Colors are for dry soil unless otherwise stated. When described on July 10, 1980, the soil was dry to 45 inches and moist below.)

Oi--0 inch to 1; decomposed and partially decomposed conifer needles, black oak leaves, twigs and bark.

A--1 to 8 inches; brown (7.5YR 5/4) gravelly loam, brown (7.5YR 4/4) moist; moderate fine and medium subangular blocky and moderate very fine and fine granular structure; slightly hard, friable, slightly sticky and slightly plastic; many very fine, fine and medium and common coarse roots; many very fine, fine and medium and common coarse interstitial pores; 30 percent gravel 2 to 30mm in diameter; slightly acid (pH 6.4); clear wavy boundary. (5 to 10 inches thick).

BAt--8 to 18 inches; brown (7.5YR 5/4) very gravelly loam, strong brown (7.5YR 4/6) moist; moderate fine and medium subangular blocky and moderate very fine and fine granular structure; slightly hard, friable, slightly sticky and slightly plastic; many very fine, fine medium and coarse roots; many very fine, fine, medium and common coarse interstitial pores; few thin clay films on peds and in pores; 40 percent gravel 2 to 30mm in diameter; slightly acid (pH 6.2); gradual wavy boundary. (8 to 15 inches thick).

Bt1--18 to 32 inches; strong brown (7.5YR 5/6) very gravelly loam, yellowish red (5YR 5/6) moist; strong fine and medium subangular blocky structure; slightly hard, friable, slightly sticky and plastic; many fine and medium roots; common very fine, fine and medium interstitial pores; common moderately thick clay films on peds and in pores; 30 percent of peds with dark reddish brown (5YR 3/2) stains coating surfaces; 50 percent gravel 2 to 50mm in diameter; moderately acid (pH 5.8); gradual wavy boundary. (10 to 25 inches thick).

Bt2--32 to 60 inches; strong brown (7.5YR 5/6) very gravelly loam, yellowish red (5YR 5/6) moist; strong fine and medium subangular blocky structure; slightly hard, friable, slightly sticky and slightly plastic; common fine and medium and few very fine and coarse roots; common very fine, fine and medium interstitial pores; common moderately thick clay films on peds and in pores; 60 percent of peds with dark reddish brown (5YR 3/2) stains coating surfaces; 55 percent gravel 2 to 75mm in diameter; moderately acid (pH 5.6); clear wavy boundary. (20 to 30 inches thick).

Bt3--60 to 64 inches; strong brown (7.5YR 5/6) very gravelly loam, yellowish red (5YR 5/6) moist; moderate fine and medium subangular blocky structure; hard, firm, slightly sticky and slightly plastic; few very fine and fine roots; common very fine, fine and medium interstitial pores; common moderately thick clay films on peds and in pores; 70 percent of peds with dark reddish brown (5YR 3/2) stains coating surfaces; 55 percent hard gravel and 15 percent soft sandstone pebbles that crush to clay loam, 2 to 75mm in diameter; moderately acid (pH 5.6).

TYPE LOCATION: Lake County, California; in Mendocino National Forest, 50 feet downslope of Road 1N02 at a point 0.4 mile south of its intersection with Road 17N23; about 1,900 feet south and 2,200 feet west of the northwest corner of sec. 4, T. 17 N., R. 10 W., Elk Mountain, Quadrangle. 39 degrees North latitude, 21 minutes, 31 seconds, 122 degrees West longitude, 59 minutes, 37 seconds.

RANGE IN CHARACTERISTICS: Thickness of the solum is 60 to 80 inches. The mean annual soil temperature is 53 degrees to 58 degrees F. The soil temperature exceeds 41 degrees F from mid February to late December and exceeds 47 degrees F from mid March to late November. The soil moisture control section (8 to 28 inches) is dry in all parts from early July to mid October (105 days) and is moist in all parts from mid December to mid May. The particle-size control section (17 to 37 inches) is 25 to 35 percent clay and 35 to 60 percent sandstone rock fragments. Base saturation is 60 to 70 percent at the surface and decreases with depth to about 50 percent.

The A horizon color is 10YR 4/2, 4/3, 4/4, 5/2, 5/3, 5/4, 6/3, 7/3; 7.5YR 4/4, or 5/4. Moist color 10YR 4/2, 4/3, 4/4, 3/3, 3/2, 2/2; 7.5YR 4/2 or 4/4. The texture is mainly gravelly loam and commonly is 18 to 25 percent clay and 15 to 75 percent gravel. Reaction is neutral to strongly acid.

The Bt horizon color is 10YR 7/4, 7.5YR 4/4, 5/4, 5/6, 6/6, 7/6; 5YR 4/6, 5/6 and 6/6. Moist color is 10YR4/4, 7.5YR 4/4, 4/6, 5/6; 5YR 4/4, 4/6, 5/4, or 5/6. Chromas are greater than 4 in at least the lowest Bt2 horizon. The texture is very gravelly loam or very gravelly clay loam and commonly is 22 to 35 percent clay. The clay content continues to increase in the lower part of the Bt horizon and increases or decreases only slightly in the lowest Bt horizon. Total rock fragments range from 35 to 60 percent, and consist of cobbles that range from 0 to 10 percent and pebbles that range from 35 to 55 percent. It is slightly acid to strongly acid.

COMPETING SERIES: These are the Bottlerock, Janscel (T), Kinkel and Southpac (T) series. Bottlerock soils have obsidian fragments and are dominated by amorphous properties. Janscel soils are dry for less than 100 days. Kinkel soils have less than 18 percent clay in the particle-size control section and have a of 47 degrees to 53 degrees F. Southpac soils have MAST of 47 to 52 degrees F.

GEOGRAPHIC SETTING: Bamtush soils are on mountains. Slopes are 15 to 75 percent. The soil formed in material weathered from hard sandstone, shale and greenstone. Elevations are 2,200 to 5,000 feet. The climate is subhumid with warm dry summers and cool moist winters. The average annual precipitation is 35 to 60 inches. Snowfall is 10 to 35 inches. Mean January temperature is about 36 degrees F, mean July temperature is about 66 degrees F, mean annual temperature varies from 47 degrees to 56 degrees F. Frost-free season is 90 to 180 days.

GEOGRAPHICALLY ASSOCIATED SOILS: These are the Deadwood, Kekawaka, Neuns, Sanhedrin, and Speaker soils. Deadwood and Neuns soils lack argillic horizons. Kekawaka soils are fine. Sanhedrin and Speaker soils are fine-loamy.

DRAINAGE AND PERMEABILITY: Well drained; low to high runoff; moderate to moderately slow permeability.

USE AND VEGETATION: This soil is used mainly for timber production, recreation, watershed, and wildlife habitat. Natural vegetation is Douglas-fir, ponderosa pine, sugar pine, California black oak, Pacific madrone and manzanita.

DISTRIBUTION AND EXTENT: Coast Range of Northern California. The series is not extensive. MLRA is 5.

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

SERIES ESTABLISHED: Lake County, California, 1983.

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

Ochric epipedon--the zone from the surface to a depth of 7 inches (A1).
Argillic horizon--the zone from 17 to 61 inches (Bt1, Bt2)

Particle-size control section--the zone from 17 to 31 inches (Bt1, Bt2).

Type location shows soil to be superactive whereas conceptually, the soil was assumed to be semiactive during Colusa County PFR (based on similar soils).

ADDITIONAL DATA: NSSL pedon S83CA-105-010 (type location)

Grab sample NSSL data on Bt1 and Bt2 horizons (sample numbers 797755 and 797756, respectively) from type location is available. Clay content in the Bt1 is 24 percent. Base saturation (by ammonium acetate) in the Bt2 is 50 percent. pH (1:1) in Bt1 and Bt2 is 5.7 and 5.6, respectively. Mineralogy is mixed with appreciable amounts of kaolinite and vermiculite.

National Cooperative Soil Survey
U.S.A.