LOCATION GRAVESUMIT CA
Established Series
REV: LJL/PBF/ET
04/2015
GRAVESUMIT SERIES
The Gravesumit series consists of very deep, well drained soils that formed in mixed alluvium. Gravesumit soils are on fan remnants. Slope ranges from 0 to 8 percent. The mean annual precipitation is about 5 inches and the mean annual air temperature is about 66 degrees F.
TAXONOMIC CLASS: Coarse-loamy, mixed, superactive, thermic Typic Calciargids
TYPICAL PEDON: On Gravesumit-Cajon-Livefire complex, 2 to 4 percent slopes at an elevation of 1,986 feet. (Colors are for dry soil unless otherwise noted.) The surface is covered by approximately 50 percent gravel.
A -- 0 to 2 inches; pale brown (10YR 6/3) very gravelly loamy sand, brown (10YR 4/3) moist; moderate medium and coarse platy structure; slightly hard, very friable, nonsticky and nonplastic; common very fine roots; common very fine interstitial pores; 50 percent gravel; slightly effervescent; moderately alkaline (pH 8.0); clear smooth boundary. (1 to 3 inches)
C -- 2 to 10 inches; pale brown (10YR 6/3) loamy coarse sand, brown (10YR 5/3) moist; massive; soft, very friable, nonsticky and nonplastic; few very fine, fine, and medium roots; common very fine interstitial pores; 12 percent gravel; slightly effervescent; moderately alkaline (pH 8.2); abrupt smooth boundary. (4 to 15 inches)
Btk1 -- 10 to 17 inches; yellowish brown (10YR 5/6) sandy loam, yellowish brown (10YR 5/6) moist; moderate coarse subangular blocky structure; hard, very friable, slightly sticky and slightly plastic; few very fine, fine, and medium roots; common very fine, few fine tubular pores; many faint discontinuous clay films on peds and sands and gravel; 5 percent gravel; 15 percent irregular soft masses and vertical bands of lime 5 to 30 mm thick; violently effervescent; moderately alkaline (pH 8.4); clear smooth boundary.
Btk2 -- 17 to 30 inches; light yellowish brown (10YR 6/4) gravelly coarse sandy loam, dark yellowish brown (10YR 4/4) moist; massive; moderately hard, very friable, nonsticky and nonplastic; few very fine and fine roots; common very fine interstitial, few very fine tubular pores; common faint discontinuous clay films on sands and gravel; 30 percent gravel; 15 percent irregular soft masses and vertical bands of lime 5 to 30 mm thick; noneffervescent; strongly alkaline (pH 8.6); diffuse wavy boundary.
Btk3 -- 30 to 70 inches; light yellowish brown (10YR 6/4) sandy loam, yellowish brown (10YR 5/6) moist; moderate medium and coarse subangular blocky structure; hard, very friable, slightly sticky and slightly plastic; few very fine tubular pores; common faint discontinuous clay films on peds and sands and gravel; 5 percent gravel; 15 percent irregular soft masses and vertical bands of lime 5 to 30 mm thick; noneffervescent; strongly alkaline (pH 8.6). (Combined thickness of the Btk horizon is 6 to 60 inches.)
TYPE LOCATION: San Bernardino County, California; about 2,200 feet west and 700 feet north of the southeast corner of section 27, T. 13 N., R. 4 E., 35 degrees, 11 minutes, 08 seconds north latitude and 116 degrees, 32 minutes, 32 seconds west longitude; East of Langford Well USGS 7.5 minute quadrangle; UTM 11S, 0541676e 3893707n (DATUM: NAS-C).
RANGE IN CHARACTERISTICS:
Soil moisture control section: Usually dry, moist in some part for short periods during winter and early spring and for 10 to 20 days cumulative between July and October following convection storms. The soils have a Typic-Aridic moisture regime.
Soil temperature: 63 to 72 degrees F.
Surface rock fragments: 15 to 65 percent gravel
Control section -
Clay content: averages 12 to 18 percent
Rock fragments: 8 to 30 percent, mainly gravel
Organic matter: 0 to 0.5 percent
A horizon
Value: 5 to 7 dry, and 4 or 5 moist
Chroma: 3 or 4, dry or moist
Texture of the fine earth: loamy sand, loamy coarse sand,
or sandy loam
Clay content: 4 to 10 percent
Rock fragments: 35 to 65 percent
Effervescence: noneffervescent or slightly effervescent
Reaction: slightly or moderately alkaline
Calcium carbonate equivalent: 0 to 1 percent
C horizon
Value: 5 to 7 dry, 4 or 5 moist
Chroma: 3 or 4, dry or moist
Texture of the fine earth: coarse sand, sand, loamy coarse
sand, loamy sand,or sandy loam
Clay content: 3 to 10 percent
Rock fragments: averages 10 to 35 percent
Effervescence: noneffervescent or slightly effervescent
Reaction: slightly or moderately alkaline
Calcium carbonate equivalent: 0 to 1 percent
Btk and Bt horizon
Hue: 7.5YR or 10YR
Value: 5 to 7 dry, and 4 to 6 moist
Chroma: 3 to 6 dry, and 4 or 6 moist
Texture of the fine earth: sandy loam, coarse sandy loam
or loam
Clay content: 8 to 18 percent
Rock fragments: ranges from 5 to 30 percent; with 5 to 30 percent gravel and
0 to 3 percent cobbles
Effervescence: slightly to violently effervescent
Reaction: slightly to strongly alkaline
Calcium carbonate equivalent: 5 to 15 percent
Other features: 3 to 30 percent secondary lime in the
form of horizontal and vertical banding and irregular
masses
Ck horizon (some pedons do not have a Ck horizon)
Hue: 7.5YR or 10YR
Value: 5 to 7 dry, and 4 to 7 moist
Chroma: 2 to 6 dry, and 3 to 6 moist
Texture of the fine earth: loamy coarse sand or loamy
sand
Clay content: 2 to 5 percent
Rock fragments: ranges from 10 to 45 percent; with 10
to 45 percent gravel and 0 to 2 percent stones and cobbles
Effervescence: very slightly effervescent to violently
effervescent
Reaction: slightly to strongly alkaline
Calcium carbonate equivalent: 1 to 15 percent
COMPETING SERIES: These are the
Onite (NM) and
Yucca (NM) series. Both of these soils are moist in some part of the moisture control section for more than 20 days, cumulative, between July and September.
GEOGRAPHIC SETTING: Gravesumit soils are on fan remnants. Slope ranges from 0 to 8 percent. The soils formed in mixed alluvium. Elevations are 1,600 to 3,800 feet. The climate is arid with hot, dry summers and warm, moist winters. Most precipitation comes in winter but a significant portion is received between July and September following convection storms. The mean annual precipitation is 2 to 7 inches; mean annual air temperature is 61 to 70 degrees F., and the frost-free season is 240 to 340 days.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the
Bluepoint,
Eastrange,
Goldivide,
Livefire, and
Thermopyl soils. Bluepoint and Livefire soils are on adjacent fan aprons, have a sandy particle-size control section, and do not have an argillic or calcic horizon. Eastrange soils are on convex remnants, have a sandy-skeletal particle-size control section, and do not have an argillic horizon. Goldivide soils are on similar landscape positions but do not have a calcic horizon. In addition, they have an argillic horizon with an upper boundary beginning at 14 or more inches from the surface. Thermopyl soils are on similar landscape positions but do not have an argillic horizon.
DRAINAGE AND PERMEABILITY: Well drained; very low through medium runoff; moderate or moderately rapid permeability. Sandy substratum phases are recognized with moderately rapid over rapid permeability.
USE AND VEGETATION: Gravesumit soils are used for military exercises and wildlife habitat. The present vegetation is mainly creosotebush and white bursage.
DISTRIBUTION AND EXTENT: Mojave Desert of southeastern California. MLRA 30. These soils are of moderate extent.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: PHOENIX, ARIZONA
SERIES ESTABLISHED: San Bernardino County, California, Fort Irwin Soil Survey Area, 2000. The name is from Grave Summit, a location within the soil survey area.
Diagnostic horizons and features recognized in the profile are:
1. Ochric epipedon -- 0 to 10 inches (A and C horizons)
2. Argillic horizon -- 10 to 70 inches (Btk horizons)
3. Calcic horizon -- 10 to 70 inches (Btk horizons)
4. Particle-size control section -- 10 to 30 inches (Btk1
and Btk2 horizons)
Responsibility for this series was transferred from Davis to Phoenix 4/2015. The last revision to the series was 6/2000. ET
National Cooperative Soil Survey
U.S.A.