LOCATION KEPHART CAEstablished Series
TAXONOMIC CLASS: Fine-loamy, mixed, superactive, mesic Vitrandic Haploxeralfs
TYPICAL PEDON: Kephart very gravelly loamy coarse sand on a northeast facing 2 percent slope under a cover of ponderosa pine, antelope bitterbrush, cheatgrass, and squirreltail at an elevation of 4,600 feet. (Colors are for dry soil unless, otherwise stated. When described July 12, 1984,the soil was dry throughout)
Oi--3 to 0 inches; recent and decomposing pine litter.
A--0 to 3 inches; dark grayish brown (10YR 4/2) very gravelly loamy coarse sand; very dark grayish brown (10YR 3/2) moist; weak very fine subangular blocky structure; soft, very friable, nonsticky and nonplastic; few very fine and medium, and common fine roots; few very fine interstitial pores; 40 percent pumice gravel; slightly acid (pH 6.2); abrupt smooth boundary. (2 to 5 inches thick)
C--3 to 8 inches; light brownish gray (10YR 6/2) extremely gravelly coarse sand; dark grayish brown (10YR 4/2) moist; single grain; loose, nonsticky and nonplastic; common very fine and few fine roots; few very fine interstitial pores; 90 percent pumice gravel; slightly acid (pH 6.2); abrupt smooth boundary. (5 to 12 inches thick)
Ab1--8 to 12 inches; brown (7.5YR 5/4) coarse sandy loam; dark brown (7.5YR 3/4) moist; moderate fine subangular blocky structure; slightly hard, friable, nonsticky and slightly plastic; common fine and medium roots; common fine tubular pores; 10 percent gravel; slightly acid (pH 6.4); abrupt smooth boundary.
Ab2--12 to 19 inches; brown (7.5YR 5/4) coarse sandy loam; dark brown (7.5YR 3/4) moist; weak very fine subangular blocky structure; slightly hard, friable, nonsticky and slightly plastic; many fine and common medium roots; common very fine tubular pores; 10 percent gravel; slightly acid (pH 6.4); abrupt smooth boundary. (Combined thickness of the Ab horizon is 7 to 21 inches)
Bwb--19 to 25 inches; brown (7.5YR 5/4) sandy loam; dark brown (7.5YR 3/4) moist; weak fine subangular blocky structure; slightly hard, friable, slightly sticky and slightly plastic; many fine, common medium, and few coarse roots; common very fine tubular pores; 10 percent gravel; slightly acid (pH 6.4); clear smooth boundary. (5 to 8 inches thick)
Btb1--25 to 35 inches; brown (7.5YR 5/4) sandy clay loam; brown (7.5YR 4/4) moist; moderate medium subangular blocky structure; hard, friable, slightly sticky and slightly plastic; common fine, few medium and coarse roots; few very fine tubular pores; common thin clay films in pores; 10 percent gravel; slightly acid (pH 6.4); gradual smooth boundary.
Btb2--35 to 44 inches; yellowish brown (10YR 5/4) sandy clay loam; dark yellowish brown (10YR 4/4), and moist; moderate medium subangular blocky structure; hard, firm, slightly sticky and slightly plastic; common fine, and few medium and coarse roots; few very fine tubular pores; common thin clay films in pores; 10 percent gravel; neutral (pH 6.6); gradual smooth boundary.
Btb3--44 to 54 inches; light yellowish brown (10YR 6/4) sandy clay loam; dark yellowish brown (10YR 4/4) moist; moderate medium subangular blocky structure; hard, firm, slightly sticky and slightly plastic; common fine, and few medium and coarse roots; common very fine tubular pores; common moderately thick clay films in pores; 10 percent gravel; neutral (pH 6.6); gradual smooth boundary.
Btb4--54 to 68 inches; light yellowish brown (10YR 6/4) sandy clay loam; dark yellowish brown (10YR 4/4) moist; moderate medium subangular blocky structure; hard, firm, slightly sticky and slightly plastic; few fine roots; common very fine tubular pores; common moderately thick clay films in pores; 10 percent gravel; neutral (pH 6.6). (Combined thickness of the Btb horizon is 29 to 43 inches or more)
TYPE LOCATION: Modoc County, California; about 6.3 miles southwest of Tionesta; 200 feet south and 2,400 feet west of the northeast corner of sec. 16, T. 43 N.,R. 5 E., Timber Mtn. SW (West of Kephart) quadrangle (7.5 minute series).
RANGE IN CHARACTERISTICS: Depth to bedrock is greater than 60 inches. The mean annual soil temperature is 47 to 50 degrees F. The soil temperature exceeds 41 degrees F.
f.om mid March to late December (285 days) and exceeds 47 degrees F. from early May to early December. The soil moisture control section (16 to 32 inches) is dry in all parts from mid July to about mid October (90 to 130 days) and is moist in all parts from early November to early July. The particle-size control section (25 to 45 inches) ranges from 20 to 27 percent clay and 5 to 15 percent rock fragments. Some pedons have a C horizon below 60 inches.
The A horizon color is 10YR 5/1, 4/2, 5/2, 6/2. Moist color is 10YR 4/1, 3/2, 4/2, 3/3. Organic matter ranges from 2.0 to 5 percent. Clay content ranges from 3 to 10 percent. Rock fragments, mostly pumice gravel range from 35 to 60 percent. NaF pH ranges from 8.0 to 8.8.
The C horizon color is 10YR 6/2, 7/2, 8/2 or 8/1. Moist color is 10YR 4/2, 6/2, 7/2. Organic matter ranges from 1 to 2 percent. Clay content ranges from 1 to 5 percent. Rock fragments, mostly pumice gravel range from 60 to 90 percent. NaF pH ranges from 9.6 to 10.0.
The Ab horizon color is 7.5YR 5/4, or 10YR 5/4. Moist color is 7.5YR 3/4 or 10YR 3/4. Organic matter ranges from 0.95 to 1.5 percent. Clay content ranges from 10 to 18 percent. Rock fragments, mostly gravel range from 5 to 15 percent. NaF pH ranges from 8.6 to 10.0. Volcanic glass content ranges from 5 to 12 percent. Aluminum and 1/2 iron (ammonium oxalate) ranges from 0.5 to 1.0.
The Bwb horizon color is 7.5YR 5/4, or 5/6. Moist color is 7.5YR 3/4, or 4/4. Organic matter ranges from 0.6 to 0.8 percent. Clay content ranges from 12 to 20 percent. Rock fragments, mostly gravel range from 5 to 15 percent. NaF pH ranges from 8.5 to 9.0. Volcanic glass content ranges from 5 to 13 percent. Aluminum and 1/2 iron (ammonium oxalate) ranges from 0.5 to 1.0.
The Btb horizon color is 7.5YR 5/4, 5/6, 10YR 5/3, 5/4 or 6/4. Moist color is 7.5YR 3/4, 4/4, 4/6 or 10YR 4/4. Organic matter ranges from 0.3 to 0.5 percent. Clay content ranges from 20 to 27 percent clay. Rock fragments mostly gravel range from 5 to 15 percent. NaF pH ranges from 8.6 to 9.0. Reaction ranges from slightly acid to neutral.
Andic Properties Data: (see remarks for explanation):
Depth P-ret B.D. pH Naf Glass Alo Feo 15barH20 0-3 15 ND 8.4 ND 0.20 0.18 6.9
3-8 ND ND ND ND ND ND ND
8-12 55 ND 8.6 12 0.65 0.98 9.1
12-19 51 0.90 8.7 11 0.50 0.75 8.3
19-25 49 0.90 8.8 ND 0.59 0.87 8.2
25-35 49 1.11 8.7 ND 0.53 0.69 9.5
35-44 42 ND 8.8 ND 0.50 0.84 9.5
44-54 ND ND ND ND ND ND 7.5
54-68 43 ND 8.8 ND 0.43 0.66 12.3
COMPETING SERIES: There are no competing series.
GEOGRAPHIC SETTING: Kephart soils are on lava plateaus and escarpments. Slopes are 2 to 30 percent. These soils formed in tephra over basaltic lava. Elevation is 4400 to 4750 feet. The climate is subhumid with warm dry summers and cold moist winters. Mean annual precipitation is 16 to 25 inches. Snowfall is 48 to 60 inches. The mean annual temperature is 45 to 48 degrees F. The mean January temperature is about 32 degrees F. The mean July temperature is about 65 degrees F. Frost-free season is 80 to 100 days.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the Medlake and Quaking (T) soils. Medlake soils are on hills, are deep and are pumiceous over medial. Quaking soils are on lava flow ridges and escarpments, are very deep and are loamy-skeletal.
DRAINAGE AND PERMEABILITY: Well drained; slow to rapid runoff; moderately slow permeability.
USE AND VEGETATION: This soil is used for timber production. The natural vegetation is ponderosa pine, incense cedar, antelope bitterbrush, greenleaf, manzanita, squirreltail, bloomer soldenbush, and some white-fir.
DISTRIBUTION AND EXTENT: Northeastern California. The soils are not extensive. MLRA is 22.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Davis, California
SERIES ESTABLISHED: Modoc County, Intermountain Soil Survey Area, California 1994. Source of name is Kephart crossing on the Great Northern Railway.
REMARKS:
Diagnostic horizons and features recognized in this profile are:
Ochric epipedon-the zone from the soil surface to about 3 inches (A).
Argillic horizon- the zone from 25 to 68 inches. (Btb1, Btb2, Btb3, Btb4).
Rock fragments, mostly pumice gravel, on the soil surface, range from 20 to 50 percent.
Andic properties data defined and referenced in the soil taxonomy andisol amendment:
Used field textures due to poor dispersion.
P-ret: phosphate retention of the less than 2mm fraction.
B.D.: bulk density of the less than 2mm fraction measured at 33kPa water retention.
pH NaF: pH of soil mixed with saturated sodium floride solution.
Glass: percent volcanic glass.
Alo: acid-oxalate-extractable aluminum of the less than 2mm fraction.
Feo: acid-oxalate-extractable iron of the less than 2mm fraction.
15 bar H20: dried 1500 kPa water retention as a percent.
Data elements with an * are estimated.
NC: not calculated.
ND: not done.
ADDITIONAL DATA: This pedon was characterized by UC Davis in 1984. Sample number is CA-85-049-0IX unpublished. UCD Lab# 1617.