LOCATION MEDLAKE CAEstablished Series
TAXONOMIC CLASS: Pumiceous or ashy-pumiceous over medial, mixed, nonacid, frigid Vitrandic Xerorthents
TYPICAL PEDON: Medlake gravelly coarse sandy loam on a NE facing 7 percent slope under a cover of Ponderosa pine, white fir, greenleaf manzanita and antelope bitterbrush at an elevation of 4,880 feet. Colors are for dry soil unless other wise stated. When described May 23, 1984 the soil was slightly moist throughout.
0i--1 to 0 inch; recent decomposed pine litter.
A1--0 to 2 inches; gray (10YR 5/1) gravelly coarse sandy loam, black (10YR 2/1) moist; weak very fine subangular blocky structure; loose, nonsticky and nonplastic; common very fine and fine roots; few very fine interstitial pores; 30 percent pumice gravel; NaF pH 8.0; moderately acid (pH 6.0); abrupt smooth boundary. (2 to 4 inches thick)
A2--2 to 6 inches; light gray (10YR 6/1) very gravelly loamy coarse sand, very dark gray (10YR 3/1) moist; weak very fine subangular blocky structure; loose, nonsticky and nonplastic; common fine roots; few fine interstitial pores; 40 percent pumice gravel; NaF pH 11.5; slightly acid (pH 6.4); abrupt smooth boundary. (2 to 6 inches thick)
C1--6 to 20 inches; white (10YR 8/1) extremely gravelly coarse sand; white (10YR 8/2) moist; single grained; loose, nonsticky and nonplastic; few very fine roots; few very fine interstitial pores; 90 percent pumice gravel; NaF pH 11.0; slightly acid (pH 6.4); abrupt smooth boundary.
C2--20 to 31 inches; white (10YR 8/1) extremely gravelly coarse sand; white (10YR 8/2) moist; single grained; loose, nonsticky and nonplastic; few very fine roots; few very fine interstitial pores; 90 percent pumice gravel; NaF pH 11.0; slightly acid (pH 6.4); abrupt smooth boundary.
C3--31 to 32 inches; white (10YR 8/1) extremely gravelly coarse sand, white (10YR 8/2) moist; single grained; loose, nonsticky and nonplastic; few very fine roots; few very fine interstitial pores; 90 percent pumice gravel; NaF pH 11.0; slightly acid; (pH 6.4) abrupt smooth boundary. (Combined thickness of the C horizon is 20 to 30 inches)
2Ab--32 to 43 inches; brown (7.5YR 5/4) gravelly coarse sandy loam, dark brown (7.5YR 3/4) moist; moderate fine subangular blocky structure; soft, friable, nonsticky and nonplastic; common very fine and medium roots; few very fine interstitial pores; 20 percent fine gravel; NaF pH 10.5; moderately acid (pH 6.0); gradual smooth boundary. (10 to 12 inches)
2Bwb1--43 to 69 inches; light brown (7.5YR 6/4) gravelly coarse sandy loam, brown (7.5YR 4/4) moist; moderate fine subangular blocky structure; soft, friable, nonsticky and nonplastic; few fine and medium roots; few very fine interstitial pores; 20 percent fine gravel; NaF pH 10.0; moderately acid (pH 6.0); gradual smooth boundary. (25 to 35 inches)
2Bwb2--69 to 75 inches; light brown (7.5YR 6/4) sandy loam, brown (7.5YR 4/4) moist; moderate fine subangular blocky structure; soft, friable, nonsticky and nonplastic; few fine roots; common very fine tubular pores; few thin clay films in pores; NaF pH 10.0; moderately acid (pH 6.0).
TYPE LOCATION: Modoc County, California; about 7.2 miles southwest of Tionesta, 2500 feet east and 2900 south from the northwest corner of Sec 6, T.43N., R.5E., Timber Mountain NW (Caldwell Butte) quadrangle (7.5 minute series).
RANGE IN CHARACTERISTICS: Depth to bedrock is greater than 60 inches and thickness of pumaceous material is 20 to 36 inches. The mean annual soil temperature ranges from 40 to 46 degrees F. The soil temperature exceeds 41 degrees F. from mid May to mid November (185 days) and exceeds 47 degrees F. from early July to early October. The soil moisture control section (36 to 58 inches) is dry in all parts from mid July to mid October and ranges from 75 to 90 days and is moist in all parts from early December to about early June. The particle-size control section (10 to 40 inches) averages 6 to 9 percent clay. Organic matter ranges from 3 to 13 percent to a depth of 6 inches and is 0.4 to 0.8 percent to a depth of 75 inches. Rock fragments, mostly pumice gravel, on the surface range from 60 to 70 percent.
The A horizon color is 10YR 5/1, 6/1, 6/2 or 7/2. Moist color is 10YR 2/1, 3/1 or 4/2. Clay content ranges from 3 to 10 percent. Texture is sandy loam, coarse sandy loam and loamy coarse sand. Rock fragments, mostly pumice gravel range from 25 to 50 percent. Base saturation by ammonium acetate ranges from 40 to 45 percent. Reaction ranges from moderately acid to slightly acid. NaF pH range from 8.0 to 11.5.
The C horizon color is 10YR 7/3 or 8/1. Moist color is 10YR 6/3, 7/2 or 8/2. Clay content ranges from 3 to 5 percent. Rock fragments, mostly pumice gravel range from 70 to 90 percent. Base saturation by ammonium acetate ranges from 40 to 45 percent. Reaction ranges from slightly acid to neutral. NaF pH ranges from 9.0 to 11.0.
The 2Ab horizon color is 7.5YR 5/4, 6/2 or 6/3. Moist color is 7.5YR 3/2, 3/4 or 4/4. Clay content ranges from 10 to 18 percent. Rock fragments, mostly andesitic gravel range from 15 to 30 percent. Base saturation by ammonium acetate ranges from 65 to 74 percent. Reaction ranges from moderately acid to neutral. NaF pH ranges from 9.0 to 10.5.
The 2Bwb horizon color is 7.5YR 5/4 or 6/4. Moist color is 7.5YR 3/4 or 4/4. Texture is sandy loam and gravelly sandy loam. Clay content ranges from 10 to 18 percent. Rock fragments, mostly andesitic gravel range from 15 to 25 percent and cobbles range from 0 to 35 percent. Base saturation by ammonium acetate ranges from 65 to 74 percent.
Andic property data (see remarks for explanation): Depth P-ret B.D. pH NaF Glass Alo Feo 15 barH20 0-2 13 1.0 7.4
ND 0.09 0 21. 2-6 10 ND 8.9 87 0.09 0 10.5 6-31 6 ND ND 81 0.06 0 ND 31-43 70 1.2 9.8 11 1.33 0.73 12.3 43-69 57 1.0 9.1 8 0.91 0.88 15.7 69-75 43 1.1
8.7 ND 0.56 0.90 16.0
COMPETING SERIES: There are no other series in this family.
GEOGRAPHIC SETTING: Medlake soils are on hills. Slopes are 2 to 30 percent. These soils formed in windlain pumiceous material deposited over older tephra. Elevation is 4800 to 5300 feet. The climate is subhumid with warm dry summers and cold moist winters. Mean annual precipitation is 25 to 35 inches. Snowfall is 48 to 60 inches. The mean annual temperatures is 39 to 44 degrees F. The mean January temperature is about 27 degrees F. The mean July temperature is about 60 degrees F. Frost-free period is 50 to 80 days.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the Blankout, Medici and Tionesta soils. Blankout soils are on hills, are very deep and are medial over loamy. Medici soils are on hills, are very deep and are medial over loamy-skeletal. Tionesta soils are on hills, are very deep, have pumice 5 to 12 inches thick on the surface and are pumiceous or ashy pumiceous over medial-skeletal.
DRAINAGE AND PERMEABILITY: Somewhat excessively drained; slow to rapid runoff; moderately rapid permeability.
USE AND VEGETATION: This soil is used for timber production. The vegetation is ponderosa pine, white fir, sugar pine, greenleaf manzanita, antelope bitterbrush, squirreltail and Incense cedar.
DISTRIBUTION AND EXTENT: Northeast 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 coined.
REMARKS: Diagnostic horizons and features recognized in this pedon are:
Ochric epipedon - the zone from 0 to 2 inches (A1).
Cambic horizon - the zone from 43 to 75 inches (2Bwb1, 2Bwb2).
Andic properties data definitions:
P-ret: phosphate retention of the less than 2mm fraction.
B.D.: bulk density of the less than 2mm fraction on an oven dry basis.
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 a * are estimated.
NC: not calculated.
ND: not done.
ADDITIONAL DATA: This pedon was characterized by UC Davis Laboratory in 1984. Sample number is #1622 unpublished.