LOCATION STUMPATIL CAEstablished Series
TAXONOMIC CLASS: Loamy-skeletal, isotic Umbric Xeric Haplocryalfs
TYPICAL PEDON: Stumpatil very gravelly coarse sandy loam--forest land. (Colors are for dry soil unless otherwise noted.) The soil surface is covered with 35 percent gravel, 5 percent stones, and 5 percent boulders.
A1--0 to 6 inches; dark grayish brown (10YR 4/2) very gravelly coarse sandy loam, very dark brown (10YR 2/2) moist; weak fine and medium subangular blocky structure; soft, very friable, nonsticky and nonplastic; common very fine and few fine roots; common very fine interstitial and tubular pores; 50 percent gravel and 5 percent boulders; moderately acid; clear wavy boundary. (4 to 8 inches thick)
A2--6 to 11 inches; brown (10YR 5/3) very gravelly coarse sandy loam, dark brown (10YR 3/3) moist; weak medium subangular blocky structure; soft, very friable, nonsticky and nonplastic; few very fine, common fine, and common medium roots; common very fine interstitial and tubular pores; 45 percent gravel and 5 percent cobbles; moderately acid; clear wavy boundary. (4 to 8 inches thick)
AB--11 to 26 inches; yellowish brown (10YR 5/4) very gravelly coarse sandy loam, dark yellowish brown (10YR 3/4) moist; moderate medium subangular blocky structure; soft, very friable, nonsticky and nonplastic; few very fine roots and many fine and medium; common very fine interstitial and tubular pores; 45 percent gravel and 10 percent cobbles; moderately acid; clear wavy boundary. (6 to 16 inches thick)
Bt--26 to 33 inches; pale brown (10YR 6/3) very gravelly sandy loam, dark yellowish brown (10YR 4/4) moist; moderate medium subangular blocky structure; slightly hard, friable, slightly sticky and nonplastic; few very fine, few fine, few medium, and common very coarse roots; few very fine interstitial and tubular pores; few faint clay films bridging sand grains; 45 percent gravel and 10 percent cobbles; moderately acid; clear wavy boundary. (6 to 12 inches thick)
Btq--33 to 60 inches; pale brown (10YR 6/3) very gravelly sandy loam, brown (10YR 4/3) moist; massive; very hard, firm and brittle, slightly sticky and nonplastic; few very fine, few fine, few medium, and common very coarse roots; few very fine interstitial and tubular pores; 20 percent distinct clay films lining pores and coating rock fragments; 15 percent discontinuous weak cementation; 45 percent gravel and 10 percent cobbles; moderately acid.
TYPE LOCATION: Alpine County, California; on the Toiyabe National Forest about 1.2 miles southeast of Red Lake; approximately 2,250 feet south and 1,000 feet east of the northwest corner of section 25, T. 10 N., R. 18 E.; USGS Carson Pass 7.5 minute topographic quadrangle; 38 degrees 41 minutes 1.3 seconds north latitude and 119 degrees 57 minutes 26.9 seconds west longitude, NAD27.
RANGE IN CHARACTERISTICS:
Soil moisture - Usually moist in the moisture control section during late fall, winter, and spring; dry from mid-July through September for 60 to 80 consecutive days in the four months following the summer solstice; Typic xeric moisture regime.
Mean annual soil temperature - 40 to 44 degrees F.
Mean summer soil temperature - 44 to 47 degrees F.
Umbric epipedon thickness - 10 to 16 inches.
Depth to argillic horizon - 26 to 40 inches.
Sodium fluoride pH - 9.5 to 11.0.
Particle-size control section - Clay content: Averages 12 to 18 percent; Rock fragments: Averages 35 to 60 percent, mainly gravel. Lithology of fragments are volcanic rocks such as tuff, granitic rocks such as granodiorite, and metamorphic rocks such as quartzite.
A horizons - Value: 4 or 5 dry, 2 or 3 moist.
Chroma: 2 or 3, dry or moist.
Organic matter content: 1 to 6 percent.
Reaction: Strongly acid or moderately acid.
AB horizon - Value: 5 or 6 dry, 3 or 4 moist.
Chroma: 3 or 4, dry or moist.
Texture: Very gravelly coarse sandy loam or very gravelly sandy loam.
Clay content: 10 to 15 percent.
Rock fragments: 35 to 60 percent.
Reaction: Strongly acid or moderately acid.
Bt horizon - Value: 5 or 6 dry, 3 or 4 moist.
Chroma: 3 or 4, dry or moist.
Texture: Very gravelly sandy loam or very gravelly coarse sandy loam.
Clay content: 13 to 18 percent.
Rock fragments: 35 to 60 percent.
Reaction: Strongly acid or moderately acid.
Btq horizon - Value: 5 or 6 dry, 3 or 4 moist.
Chroma: 3 or 4, dry or moist.
Texture: Very gravelly sandy loam or very gravelly coarse sandy loam.
Clay content: 13 to 18 percent.
Rock fragments: 35 to 60 percent.
Reaction: Strongly acid or moderately acid.
Cementation: 10 to 50 percent weak discontinuous cementation with a brittle manner of failure.
COMPETING SERIES: There are currently no other series in this family.
GEOGRAPHIC SETTING: Stumpatil soils are on moraines. They formed in till derived from mixed rocks. Slopes are 8 to 50 percent. Elevations range from 8,000 to 9,500 feet. The climate is subhumid-continental with cold, moist winters and cool, dry summers. The mean annual precipitation is 30 to 55 inches, mean annual temperature is 36 to 39 degrees F., and the frost-free period is 30 to 60 days.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the Burnlake, Florand, and Morscour soils. Burnlake soils have a frigid temperature regime and have umbric epipedons and cambic horizons. Florand soils are deep to paralithic contacts, have umbric epipedons and cambic horizons, and occur on adjacent mountains. Morscour soils are very shallow to paralithic contacts, have mollic epipedons, and occur on adjacent mountains.
DRAINAGE AND PERMEABILITY: Well drained; medium or high surface runoff; moderate permeability (moderately high or high saturated hydraulic conductivity).
USE AND VEGETATION: Stumpatil soils are used for forest land, recreation, watershed, and wildlife habitat. The native vegetation is mainly a forest canopy of California red fir, lodgepole pine, and western white pine with an understory of needlegrass, mountain brome, bluegrass, and various forbs.
DISTRIBUTION AND EXTENT: Eastern California, on the east side of the Sierra Nevada Range. These soils are not extensive with about 4,400 acres of the series mapped to date. MLRA 22A.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Davis, California
SERIES ESTABLISHED: Alpine County (Toiyabe National Forest Area), California, 2006.
REMARKS: Diagnostic horizons and features recognized in this pedon are:
Umbric epipedon - The zone from the soil surface to 11 inches (A1 and A2 horizons).
Argillic horizon - The zone from 26 to 60 inches (Bt and Btq horizons).
Particle-size control section - The zone from 26 to 46 inches (Bt horizon and part of the Btq horizon).
ADDITIONAL DATA: The typical pedon at the series type location has partial characterization data from the Soil Survey Laboratory (SSL), Lincoln, NE as soil survey sample number S99CA-003-004 (pedon # 00P0467).