LOCATION MOUNTHAT CAEstablished Series
TAXONOMIC CLASS: Medial-skeletal, mixed, frigid Pachic Melanoxerands
TYPICAL PEDON: Mounthat gravelly sandy loam is in an area of Obie-Mounthat complex, 5 to 15 percent slopes described on a SE facing 5 percent slope under a cover of White Fir at an elevation of 5100 feet. (When described on June 4,1986, the soil was moist below 4 inches). (Colors are for dry soil unless otherwise stated).
A1--0 to 4 inches; dark brown (10YR 3/3) gravelly sandy loam, black (10YR 2/1) moist; moderate very fine granular structure; soft, very friable, nonsticky and nonplastic; many very fine fine and medium roots; many very fine interstitial pores; 20 percent gravel, 10 percent cobbles; NaF pH 11.0; slightly acid (pH 6.5); clear wavy boundary.
A2--4 to 10 inches; brown (10YR 4/3) gravelly sandy loam, very dark brown (10YR 2/2) moist; weak very fine granular structure; soft, very friable, nonsticky and nonplastic; many very fine and fine and medium roots; many very fine interstitial pores; 20 percent gravel and 10 percent cobbles; NaF pH 11.0; slightly acid (pH 6.5); gradual smooth boundary. (Combined thickness of the A horizons is 8 to 15 inches)
A3--10 to 21 inches; brown (10YR 4/3) very cobbly sandy loam, very dark brown (10YR 2/2) moist; weak fine granular structure; soft, very friable, nonsticky and nonplastic; many very fine fine and medium roots; many very fine interstitial pores; 15 percent gravel and 10 percent cobbles, 15 percent stones and boulders of nonvesicular andesite; NaF pH 11.0; slightly acid (pH 6.5); clear wavy boundary. (14 to 29 inches thick)
2Bw--21 to 27 inches; brown (7.5YR 4/4) very cobbly sandy loam, dark brown (7.5YR 3/4) moist; weak very fine subangular blocky structure; soft, very friable, nonsticky and nonplastic; common very fine, fine and medium roots; many very fine interstitial pores; 10 percent gravel, 25 percent cobbles and 10 percent stones and boulders of nonvesicular andesite; slightly acid (pH 6.5); gradual wavy boundary. (4 to 10 inches thick)
2Cr--27 inches; weathered vesicular andesite with soil filled fractures.
TYPE LOCATION: Shasta County, California; about 1200 feet west and 1900 feet north of the southeast corner of section 18, T.35N., R.2E., Chalk Mtn Quadrangle (7.5 minute series).
RANGE IN CHARACTERISTICS: Depth to a paralithic contact is 20 to 40 inches. The mean annual soil temperature is 41 to 46 degrees F. The soil temperature exceeds 41 degrees F. from mid May to mid November (about 180 days) and exceeds 47 degrees F. from early July to early October. The soil moisture control section (5 to 16 inches) is dry in all parts mid August to mid October (60 days) and moist in all parts from mid November to early July. Volcanic ash is assumed to be less than 60 percent in the upper 7 to 14 inches of the profile. Reaction ranges from slightly to moderately acid throughout.
The A1 and A2 horizon color is 10YR 3/3, 4/2, 4/3; or 5YR 4/4. Moist color is 10YR 2/1, or 2/2. Organic matter ranges from 15 to 30 percent. Clay content ranges from 8 to 18 percent. Rock fragments, mostly gravel, range from 15 to 30 percent. NaF pH is 10.0 to 11.0. Base saturation by ammonium acetate ranges from 10 to 25 percent.
The A3 horizon color is 10YR 4/3, or 5/4; 7.5YR 4/4, or 5YR 4/4. Moist color is 10YR 2/2; or 7.5YR 3/2. Organic matter ranges from 6 to 10 percent. Texture is very cobbly or very gravelly sandy loam. Clay content ranges from 10 to 20 percent. Rock fragments, mostly cobbles or gravels, range from 35 to 60 percent. NaF pH is 9.0 to 10.0. Base saturation by ammonium acetate ranges from 1 to 12 percent.
The 2Bw horizon color is 10YR 4/3, 5/4; 7.5YR 4/4; or 5YR 4/4. Moist color is 10YR 4/3; 7.5YR 3/4, 4/4,. Organic matter ranges from 2 to 5 percent. Texture is very cobbly or very gravelly sandy loam. Clay content ranges from 10 to 20 percent. Rock fragments, mostly cobbles or gravel, range from 35 to 60 percent. NaF pH is 9.0 to 10.0. Base saturation by ammonium acetate ranges from 5 to 15 percent.
Andic property data (see remarks for explanation):
Depth P-ret B.D. pHNaf Glass Alo Feo 15barH2o 0-4 97 0.5 11.0 13 2.72 .79 47.3 4-10 97 0.5
11.0 7 3.17 .79 31.0 10-21 98 0.5 11.0 7 2.69 .78 27.2 21-27 84 0.5 ND 1 1.05 .76 24.5
COMPETING SERIES: There are no other soils in this family.
GEOGRAPHIC SETTING: Mounthat soils are on mountains. Slopes are 5 to 75 percent. These soils formed in material weathered from andesite and ash. Elevation is 4500 to 6500 feet. The climate is subhumid with warm dry summers and cold moist winters. Mean annual precipitation is 40 to 60 inches. Snowfall is 48 to 72 inches. The mean annual temperature is 39 to 44 degrees F. The mean January temperature is about 28 degrees F. The mean July temperature is about 58 degrees F. Frost-free season is 50 to 80 days.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the Obie, Wyntoon, Depner, Goulder and Neer soils and competing Obie soils. Obie, Wyntoon Depner and Goulder are over 40 inches deep. Wyntoon and Goulder have argillic horizons. Wyntoon, Depner and Neer have mesic temperature regime.
DRAINAGE AND PERMEABILITY: Well drained; slow to very rapid runoff; moderately rapid permeability.
USE AND VEGETATION: This soil is used for timber production. The natural vegetation is White fir, California Black Oak, Ponderosa Pine, Green leaf manzanita.
DISTRIBUTION AND EXTENT: Northern California. The soils are moderately extensive. MLRA is 22.
MLRA OFFICE RESPONSIBLE: Davis, California
SERIES ESTABLISHED: Shasta County (Intermountain Soil Survey Area), California, 1994. Source of name is Hatchet Mountain.
REMARKS: Diagnostic horizons and features recognized in this pedon are:
Melanic epipedon - the zone from 4 to 21 inches (A2, A3).
Cambic horizon - the zone from 21 to 27 inches (2Bw1).
Paralithic contact- the boundary at 27 inches (2Cr).
Particle size control section (0-21 inches): weighted average of the particle size control sections is over 35 percent.
ADDITIONAL DATA: This pedon was characterized by UCD. Sample number is 1670, unpublished.