LOCATION ALOMAX CAEstablished Series
TAXONOMIC CLASS: Loamy-skeletal, mixed, superactive, frigid Lithic Haploxerolls
TYPICAL PEDON: Alomax very stony sandy loam--on a west-facing slope of 30 percent under mountain big sagebrush and bluebunch wheatgrass at about 6,400 feet elevation--rangeland. (Colors are for dry soil unless otherwise noted. When described on September 27, 1977, the soil was dry throughout.).
A1--0 to 3 inches; dark grayish brown (10YR 4/2) very stony sandy loam, very dark brown (10YR 2/2) moist; moderate medium subangular blocky structure; slightly hard, very friable, nonsticky and nonplastic; many very fine roots; many very fine and fine interstitial pores; 30 percent stones, 10 percent cobbles, and 10 percent gravel; slightly acid (pH 6.5); clear wavy boundary. (2 to 5 inches thick)
A2--3 to 15 inches; grayish brown (10YR 5/2) extremely stony sandy loam, very dark brown (10YR 2/2) moist; massive; slightly hard, very friable, nonsticky and nonplastic; many very fine and fine roots; many very fine and fine interstitial pores; 20 percent stones, 20 percent cobbles, and 30 percent gravel; slightly acid (pH 6.5); abrupt wavy boundary. (8 to 15 inches thick)
R--15 inches; hard fractured basalt.
TYPE LOCATION: Lassen County, California; in the Skedaddle Mountains about one mile northwest of Hot Springs Peak; found by going 7.2 miles east of Big Mud Flat on the Smoke Creek Ranch Road to the first southbound road at Bull Flat, then continue south past Bull Spring to Jenkins Spring, then 3.4 miles south on a jeep trail along Pea Creek and 1,000 feet up the slope east of this trail; about 2,220 feet north and 725 feet east of the southwest corner of section 12, T. 29 N., R. 16 E.; USGS Little Mud Flat 7.5 minute topographic quadrangle; 40 degrees 23 minutes 16 seconds north latitude and 120 degrees 07 minutes 50 seconds west longitude, NAD27.
RANGE IN CHARACTERISTICS:
Soil moisture - Usually moist in winter and spring, dry in summer and fall; These soils are dry in all parts of the moisture control section from July 1 to November 1 (125 days); It is moist throughout from December 1 to May 15. The soil temperature exceeds 41 degrees F from May 1 to December 1 (214 days) and exceeds 47 degrees from May 15 to November 15; Aridic moisture regime that borders on xeric.
Mean annual soil temperature - 45 to 47 degrees F.
Depth to bedrock - 10 to 20 inches to a lithic contact.
Particle-size control section - Clay content: 10 to 15 percent; Rock fragments: Averages 40 to 70 percent, mainly stones. Lithology of fragments are volcanic rocks such as andesite or basalt.
Reaction - Slightly acid or neutral.
Other features - Rock fragments on the soil surface, mostly cobbles and stones, range from 35 to 70 percent and average about 50 percent.
A horizons - Dry color: 7.5YR or 10YR 4/2, 5/2, 4/3, or 5/3.
Moist color: 10YR 2/2, 3/2, or 3/3.
Texture: Very stony sandy loam, very cobbly sandy loam, or extremely stony sandy loam.
Organic matter content: 1 or 2 percent.
COMPETING SERIES: These are the Agassiz, Anatone, Bluecanyon, Bocker, Cedaran, Dipcreek (T), Falula, Foxol, Gando, Gomine, Grink, Hogsby, Kenypeak (T), Little Pole, Nayrib, Onaqui, Rexmont, Starglade (T), Swanner, and Van Wagoner series.
Agassiz, Anatone, Cedaran, and Little Pole soils have more than 20 percent clay in the particle-size control section. Bluecanyon soils have a xeric moisture regime and have cambic horizons. Bocker soils are very shallow, have hue of 5YR, and have a xeric moisture regime. Dipcreek soils have a xeric moisture regime. Falula soils have horizons with identifiable secondary carbonates and have mean annual soil temperature of 39 to 44 degrees F. Foxol soils have hue of 5YR, a xeric moisture regime, and are dominated by gravel in the particle-size control section. Gando soils are slightly alkaline or moderately alkaline, have horizons with identifiable secondary carbonates, and are dominated by gravel in the particle-size control section. Gomine soils have 18 to 27 percent clay in the particle-size control section and have a xeric moisture regime. Grink soils have calcic horizons and have a xeric moisture regime. Hogsby soils are dominated by channers and flagstones in the particle-size control section, have rock fragments that are argillite or quartzite, and have a xeric moisture regime. Kenypeak soils are dominated by gravel in the particle-size control section and have rock fragments that are metamorphic rocks. Nayrib soils are very shallow and are dominated by cobbles in the particle-size control section. Onaqui soils are dominated by cobbles in the particle-size control section, have rock fragments that are mainly quartzite, and have a xeric moisture regime. Rexmont soils are calcareous, have rock fragments that are limestone, and have mean annual soil temperature of 37 to 41 degrees F. Starglade soils have vitrandic intergrade features such as ashy texture and have a xeric moisture regime. Swanner soils have horizons with identifiable secondary carbonates. Van Wagoner soils have C horizons, have rock fragments that are quartz diorite, and have a xeric moisture regime.
GEOGRAPHIC SETTING: Alomax soils are on mountains. They typically occur on backslope positions. These soils formed in colluvium derived from andesite or basalt. Areas of rock outcrop, stones, and cobbles are common and occupy up to 30 percent of the surface. Slopes are 30 to 50 percent. Elevations range from 5,500 to 7,300 feet. The mean annual precipitation is 12 to 16 inches including 35 to 40 inches of annual snowfall. The mean annual temperature is 44 to 46 degrees F. The frost-free period is 60 to 80 days.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the Devada, Glean, and Longcreek soils. Devada and Longcreek soils have argillic horizons and a mesic temperature regime. Glean soils are deep to lithic contacts and have thick mollic epipedons.
DRAINAGE AND PERMEABILITY: Well drained; very high surface runoff; moderately rapid permeability.
USE AND VEGETATION: Alomax soils are used for rangeland and wildlife habitat. The vegetation is bluebunch wheatgrass, Idaho fescue, and mountain big sagebrush.
DISTRIBUTION AND EXTENT: Northeastern California. These soils are not extensive with about 4,400 acres of the series mapped to date. MLRA 23.
MLRA OFFICE RESPONSIBLE: Reno, Nevada.
SERIES ESTABLISHED: Lassen County (Susanville Area Soil Survey), California, 2000.
REMARKS: Diagnostic horizons and features recognized in this pedon are:
Mollic epipedon - The zone from the soil surface to 15 inches (A1 and A2 horizons).
Lithic contact - The boundary at 15 inches to underlying hard, unweathered bedrock (R layer).