LOCATION DEMOGUL CAEstablished Series
TAXONOMIC CLASS: Fine-loamy, parasesquic, mesic Ultic Palexeralfs
TYPICAL PEDON: Demogul gravelly loam--on a northeast facing convex slope of 60 percent under Douglas-fir, Pacific madrone, deerbrush ceanothus, California black oak, and poison oak at an elevation of 2,500 feet. (Colors are for dry soil unless otherwise stated. When described on September 29, 1983, the soil was slightly moist.)
The soil surface is partially covered by 5 percent pebbles.
Oi--2 to 0 inches; needles, twigs, and leaves.
A--0 to 4 inches; pink (5YR 7/3) gravelly loam, dark brown (7.5YR 3/4) moist; moderate very fine subangular blocky structure; soft, very friable, slightly sticky and slightly plastic; common coarse, medium and fine, many very fine roots; few medium, common fine and very fine tubular pores; 5 percent pebbles on the surface; 20 percent pebbles in the horizon; slightly acid (pH 6.5); clear wavy boundary. (3 to 5 inches thick)
BA--4 to 9 inches; reddish yellow (7.5YR 6/6) gravelly clay loam, yellowish red (5YR 4/6) moist; weak fine subangular blocky structure; slightly hard, friable, slightly sticky and slightly plastic; few coarse and medium, common fine and very fine roots; few medium, common fine and very fine tubular pores; 20 percent pebbles; slightly acid (pH 6.5); clear wavy boundary. (4 to 6 inches thick)
Bt1--9 to 21 inches; reddish yellow (7.5YR 6/6) gravelly clay loam, yellowish red (5YR 5/6) moist; moderate medium and fine subangular blocky structure; hard, friable, sticky and plastic; few coarse and medium, common fine and very fine roots; few fine, common very fine tubular pores; few thin clay films lining pores and on ped faces; 20 percent pebbles; strongly acid (pH 5.5); gradual wavy boundary. (12 to 16 inches thick)
Bt2--21 to 34 inches; reddish yellow (7.5YR 6/6) gravelly clay loam, yellowish red (5YR 5/6) moist; hard, friable, sticky and plastic; few coarse and medium, common fine and very fine roots; few fine, common very fine tubular pores; common thin clay films lining pores and on ped faces; 20 percent pebbles; strongly acid (pH 5.5); gradual wavy boundary. (12 to 20 inches thick)
Bt3--34 to 68 inches; red (2.5YR 5/6 and 4/8) gravelly clay loam, red (2.5YR 4/8) moist; moderate medium and fine subangular blocky structure; hard, friable, sticky and plastic; few medium and fine, common very fine roots; few very fine tubular pores; many thin clay films lining pores and on ped faces; 30 percent pebbles; moderately acid (pH 6.0).
TYPE LOCATION: Trinity County, California; about 1 mile southwest of Weaverville, California; take Oregon Street west from Weaverville, go 1.6 miles, turn left (south) onto dirt road, go 1.0 mile, pedon described in roadcut; 2,100 feet east, and 1,100 feet south of the northwest corner of section 13, T.33 N., R.10 W. Weaverville Quadrangle.
RANGE IN CHARACTERISTICS: The mean annual soil temperature is 52 to 59 degrees F. The soil moisture control section is dry in all parts from mid July to mid October. The soil temperature exceeds 41 degrees F from mid March to early December and exceeds 47 degrees F from about April 20 to November 10. The particle-size control section contains from 27 to 35 percent clay, 15 to 25 percent mica minerals in the very fine sand fraction, and averages 20 to 30 percent rock fragments. The particle-size control section has a ratio of extractable iron plus gibbsite to clay of 0.2 to 0.3.
The A horizon is 5YR 7/3, 6/4, 7.5YR 6/4, or 5/4. Moist color is 7.5YR 3/4, 4/4, 5YR 3/4, or 10YR 3/4. It is slightly acid or neutral.
The Bt horizon is 7.5YR 6/6, 7/6, 5/6, 5/4, 6/4, 6/6, 5YR 5/6, 6/6, 5/8, 2.5YR 5/6, or 4/8. Moist color is 5YR 5/6, 4/6, 4/4, 7.5YR 4/4, 4/6, 2.5YR 4/6, 4/8 or 5/6. Chroma is more than 4 in the lower part. The Bt horizon is gravelly clay loam or gravelly sandy clay loam but may be very gravelly clay loam, or very gravelly sandy clay loam in the lower part. It is strongly acid to slightly acid. The base saturation is 50 to 75 percent by sum of cations.
COMPETING SERIES: This is the Weaverville series. The Weaverville soils contain less than 15 percent mica minerals.
GEOGRAPHIC SETTING: The Demogul soils are on mountains at elevations of 1,700 to 3,600 feet. Slopes are 15 to 90 percent. These soils formed in colluvium weathered from mica schist. The climate is characterized by cool, moist winters and warm, dry summers. Mean annual precipitation is 30 to 50 inches. Snowfall ranges from six to 24 inches. Mean annual temperature is 50 to 57 degrees F. Mean January temperature is about 35 degrees F. Mean July temperature is about 68 degrees F. Frost-free period is 90 to 130 days.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the Dougcity and Cargent series. The Dougcity soils have greater than 35 percent rock fragments in the particle-size control section. The Cargent soils are 20 to 40 inches deep over bedrock and are on south facing slopes.
DRAINAGE AND PERMEABILITY: Well drained; rapid to very rapid runoff; moderately slow permeability.
USE AND VEGETATION: The Demogul soils are used mainly for timber production, water supply, and wildlife habitat. The vegetation is Douglas-fir, ponderosa pine, California black oak, California hazel, poisonoak, and California fescue.
DISTRIBUTION AND EXTENT: The Demogul soils are inextensive. They are in the Klamath Mountains of northern California.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Davis, California
SERIES ESTABLISHED: Trinity County, California, Weaverville Area, 1990. Soil name is from a gulch nearby.
REMARKS: Diagnostic horizons and features recognized in this pedon are:
Ochric epipedon--the zone from the surface to 9 inches (A, BA).
Argillic horizon--the zone from 9 to 68 inches (Bt1, Bt2, Bt3).
Particle-size control section--the zone from 9 to 29 inches (Bt1, Bt2).