LOCATION PINEW CAEstablished Series
TAXONOMIC CLASS: Loamy-skeletal, mixed, superactive, frigid, shallow Typic Argixerolls
TYPICAL PEDON: Pinew very gravelly sandy loam--forest land. (Colors are for dry soil unless otherwise noted.) The soil surface is covered with 25 percent gravel, 5 percent cobbles, and 4 percent stones.
A1--0 to 1 inch; brown (7.5YR 5/3) very gravelly sandy loam, dark brown (7.5YR 3/3) moist; weak fine granular structure; soft, very friable, nonsticky and nonplastic; common very fine roots; common very fine interstitial pores; 40 percent gravel; slightly acid; clear smooth boundary. (1 to 3 inches thick)
A2--1 to 3 inches; brown (7.5YR 5/3) very gravelly sandy loam, dark brown (7.5YR 3/3) moist; weak medium platy structure; soft, very friable, slightly sticky and slightly plastic; common very fine and fine roots; common very fine tubular and interstitial pores; 40 percent gravel; neutral; clear wavy boundary. (1 to 3 inches thick)
Bt1--3 to 8 inches; brown (7.5YR 5/3) very gravelly sandy clay loam, dark brown (7.5YR 3/3) moist; moderate medium subangular blocky structure; slightly hard, very friable, slightly sticky and slightly plastic; common very fine through medium roots; common very fine tubular and interstitial pores; common faint clay films bridging sand grains; 45 percent gravel; neutral; clear wavy boundary. (4 to 7 inches thick)
Bt2--8 to 15 inches; brown (7.5YR 4/3) very gravelly clay loam, dark brown (7.5YR 3/4) moist, moderate fine and medium subangular blocky structure; slightly hard, very friable, moderately sticky and moderately plastic; common very fine through medium roots; common very fine tubular and interstitial pores; common distinct clay films on faces of peds and lining pores; 50 percent gravel; 25 percent paragravel; neutral. (4 to 8 inches thick)
Cr--15 to 25 inches; fractured, weathered tuff; some roots and fine-earth in fractures.
TYPE LOCATION: Alpine County, California; on the Toiyabe National Forest about 0.75 mile south of Mogul Peak; approximately 650 feet north and 700 feet east of the southwest corner of section 30, T. 10 N., R. 21 E.; USGS Heenan Lake 7.5 minute topographic quadrangle; 38 degrees 40 minutes 44.3 seconds north latitude and 119 degrees 43 minutes 02.1 seconds west longitude, NAD27.
RANGE IN CHARACTERISTICS:
Soil moisture - Usually moist in the moisture control section during late fall, winter, and spring; dry from July through early October for 75 to 90 consecutive days in the four months following the summer solstice; Xeric moisture regime that borders on aridic.
Mean annual soil temperature - 44 to 47 degrees F.
Mollic epipedon thickness - 7 to 14 inches; includes the Bt1 horizon.
Depth to bedrock - 14 to 20 inches to a paralithic contact. The paralithic materials below the contact are weathered volcanic rocks such as andesitic tuff.
Sodium fluoride pH - 8.5 to 9.0.
Particle-size control section - Clay content: Averages 18 to 27 percent; Rock fragments: Averages 35 to 60 percent, mainly medium and coarse gravel (5 to 75 mm diameter). Lithology of fragments are volcanic rocks such as tuff, tuff-breccia, and andesite.
A horizons - Hue: 10YR or 7.5YR.
Value: 4 or 5 dry, 2 or 3 moist.
Chroma: 2 or 3, dry or moist.
Organic matter content: 2 to 4 percent.
Reaction: Slightly acid or neutral.
Bt1 horizon - Hue: 10YR or 7.5YR.
Chroma: 2 or 3, dry or moist.
Texture: Very gravelly sandy clay loam, very gravelly sandy loam, or very gravelly loam.
Clay content: 18 to 25 percent.
Rock fragments: 35 to 60 percent.
Organic matter content: 1 or 2 percent.
Reaction: Slightly acid or neutral.
Bt2 horizon - Hue: 10YR or 7.5YR.
Value: 4 through 6 dry, 3 or 4 moist.
Chroma: 2 or 3, dry or moist.
Texture: Very gravelly clay loam, very gravelly sandy clay loam, or very gravelly loam.
Clay content: 25 to 35 percent.
Rock fragments: 35 to 60 percent.
Pararock fragments: 10 to 30 percent paragravel.
Reaction: Slightly acid or neutral.
COMPETING SERIES: These are the Crispy, Cucamungo, Grandridge, Quopant, and Trailamp series.
Crispy soils have rock fragments which are metamorphic rocks and have paralithic materials of weathered schist or gneiss in the series control section. Cucamungo and Grandridge soils are dominated by fine gravel (2 to 5 mm diameter) of granitic lithology in the particle-size control section and have paralithic materials of weathered granitic rock in the series control section. Quopant soils have 2C horizons below the argillic horizon with less than 35 percent rock fragments. Trailamp soils are slightly alkaline or moderately alkaline, have paralithic contacts at depths of 7 to 14 inches, have paralithic materials of siltstone or shale in the series control section, and are intermittently moist due to summer convection storms.
GEOGRAPHIC SETTING: Pinew soils are on mountains. They typically occur on backslope positions. They formed in colluvium and residuum derived from tuff, tuff-breccia, and andesite. Slopes are 15 to 75 percent. Elevations range from 5,800 to 8,000 feet. The climate is subhumid-continental with cold, moist winters and warm, dry summers. The mean annual precipitation is 16 to 24 inches, mean annual temperature is 40 to 44 degrees F., and the frost-free period is 40 to 70 days.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the Carshal, Celeridge, and Gerdog soils. Carshal soils are very shallow and shallow, have ochric epipedons, and do not have argillic horizons. Celeridge soils are shallow to lithic contacts. Gerdog soils are very shallow and shallow to lithic contacts.
DRAINAGE AND PERMEABILITY: Well drained; very high surface runoff; moderately slow permeability (moderately high saturated hydraulic conductivity).
USE AND VEGETATION: Pinew soils are used for forest land, recreation, watershed, and wildlife habitat. The native vegetation is mainly a forest canopy of singleleaf pinyon and scattered Jeffrey pine with an understory of antelope bitterbrush, mountain big sagebrush, and bluegrass.
DISTRIBUTION AND EXTENT: Eastern California, on the east side of the Sierra Nevada Range. These soils are not extensive with about 6,400 acres of the series mapped to date. MLRAs 26 and 22A.
MLRA OFFICE RESPONSIBLE: Reno, Nevada.
SERIES ESTABLISHED: Alpine County (Toiyabe National Forest Area), California, 2006.
REMARKS: Diagnostic horizons and features recognized in this pedon are:
Mollic epipedon - The zone from the soil surface to 8 inches (A1, A2, and Bt1 horizons).
Argillic horizon - The zone from 3 to 15 inches (Bt1 and Bt2 horizons).
Paralithic contact - The boundary at 15 inches to underlying soft bedrock (Cr layer).
Particle-size control section - The zone from 3 to 15 inches (Bt1 and Bt2 horizons).
The revision of October 2003 updated the taxonomic class from Loamy-skeletal, isotic, frigid, shallow Typic Argixerolls. The isotic mineralogy class was based solely on the field determined values for sodium fluoride pH. Laboratory data on 15 bar water to clay ratio does not exist to verify the isotic mineralogy class.