LOCATION CUMINVAR CAEstablished Series
TAXONOMIC CLASS: Ashy over clayey, glassy over smectitic, nonacid, frigid Typic Endoaquents
TYPICAL PEDON: Cuminvar muck--Pasture land. (Colors are for dry soil unless otherwise noted.)
Oa--0 to 8 inches; gray (10YR 5/1) muck, black (10YR 2/1) moist; massive; soft, friable, nonsticky and nonplastic; many very fine and fine roots; many very fine and fine interstitial pores; neutral (pH 6.8); clear wavy boundary. (8 to 16 inches thick)
C--8 to 15 inches; white (10YR 8/1) ashy silt loam, gray (10YR 6/1) moist; massive; slightly hard, brittle, slightly sticky and very plastic; common very fine and fine roots; common very fine and fine tubular pores; moderately alkaline (pH 8.0); abrupt wavy boundary. (7 to 14 inches thick)
2Css1--15 to 19 inches; gray (10YR 6/1) clay, very dark gray (10YR 3/1) moist; strong medium and fine columnar structure; extremely hard, very firm, very sticky and very plastic; common very fine tubular pores; common slickensides; moderately alkaline (pH 8.2); clear wavy boundary. (2 to 6 inches thick)
2Css2--19 to 25 inches; gray (10YR 6/1) clay, dark grayish brown (10YR 4/2) moist; moderate medium prismatic parting to strong coarse angular blocky structure; extremely hard, very firm, sticky and very plastic; few very fine inped and common very fine exped roots; few very fine tubular pores; common slickensides; moderately alkaline (pH 8.2) gradual wavy boundary. (5 to 10 inches thick)
2Css3--25 to 38 inches; light brownish gray (2.5Y 6/2) clay, dark grayish brown (2.5Y 4/2) moist; moderate coarse angular blocky parting to medium and fine angular blocky structure; extremely hard, firm, sticky and very plastic; common very fine and fine roots; common fine tubular pores; common slickensides; moderately alkaline (pH 8.2) gradual irregular boundary. (6 to 14 inches thick)
2Cgk1--38 to 52 inches; 60 percent pale olive (5Y 6/3) and 40 percent light brownish gray (2.5Y 6/2) silty clay, 60 percent light olive brown (2.5Y 5/3) and 40 percent olive (5Y 5/6) moist; massive; hard, firm, sticky and very plastic; common very fine and fine roots; common very fine tubular pores; many fine and medium pale yellow (2.5Y 8/2) soft masses of lime; slightly effervescent matrix; strongly alkaline (pH 8.6) gradual wavy boundary. (8 to 15 inches thick)
2Cgk2--52 to 72 inches; 60 percent olive (5Y 5/3) and 40 percent pale olive (5Y 6/4) silty clay, 60 percent light olive gray (5Y 6/2) and 40 percent greenish gray (5GY 6/1) moist; massive; hard, slightly firm, slightly brittle, sticky and very plastic; common very fine and firm roots; few very fine tubular pores; many medium greenish gray (5BG 5/1) redox depletions in matrix; slightly effervescent matrix; strongly alkaline (pH 8.8).
TYPE LOCATION: Modoc County, California; in Surprise Valley about 1 mile east of Snake Lake; about 1,150 feet south and 1,700 feet east of the northwest corner of section 33; T.39 N., R.17 E.; Snake Lake USGS 7.5 minute topographic quadrangle; 41 degrees 12 minutes 23 seconds north latitude and 120 degrees 03 minutes 04 seconds west longitude, NAD 27.
RANGE IN CHARACTERISTICS:
Soil moisture - Usually saturated in some part of the moisture control section during winter, spring and early summer, usually dry in some part summer and fall; seasonal periods of aquic moisture regime from November through June during saturation with ground water and anaerobic conditions; Aquic moisture regime.
Mean annual soil temperature - 43 to 47 degrees F.
Histic epipedon thickness - 8 to 16 inches.
Depth to clayey discontinuity - 15 to 25 inches.
Control section - Clay content: Averages 18 to 27 percent in the upper part and 40 to 60 percent in the lower part; Rock fragments: Averages less than 5 percent.
Oa horizon - Hue: 10YR, 2.5Y or neutral.
Value: 4 or 5 dry, 2 or 3 moist.
Chroma: 1 or less dry or moist.
Organic matter content: 25 to 35 percent.
Reaction: Slightly acid or neutral.
C Horizon - Hue: 10YR, 2.5Y or neutral.
Value: 7 or 8 dry, 5 or 6 moist.
Chroma: 1 or less, dry or moist.
Texture: Ashy silt loam.
Clay content: 18 to 27 percent.
Rock fragments: Less than 5 percent.
2Css horizons - Hue: 10YR, 2.5Y or 5Y.
Value: 5 to 7 dry, 4 or 5 moist.
Chroma: 1 or 2 dry or moist.
Texture: Clay or silty clay.
Clay content: 40 to 60 percent.
Rock fragments: Less than 5 percent.
Reaction: Slightly alkaline to very strongly alkaline.
2Cgk horizons - Hue: 2.5Y or 5Y.
Value: 5 or 6 dry, 4, 5 or 6 moist.
Chroma: 2, 3 or 4 dry or moist.
Texture: Clay or silty clay.
Clay content: 40 to 60 percent.
Rock fragments: Less than 5 percent.
Reaction: Slightly alkaline to very strongly alkaline
Effervescence: Slightly effervescent to strongly effervescent in the matrix.
Carbonates: Common or many fine and medium soft lime masses in some subhorizon.
Redoximmorphic features: Redox depletions occur as masses of iron or manganese depletions in the matrix.
COMPETING SERIES: These are currently no other series recognized in this family.
GEOGRAPHIC SETTING: Cuminvar soils are on lake terraces. They formed in lacustrine material derived from volcanic rock sources with additions of volcanic ash. Slopes are 0 to 2 percent. Elevations range from 4,400 to 4,700 feet. The climate is semi-arid with cool, moist winters and warm, dry summers. The mean annual precipitation is 10 to 12 inches, mean annual temperature is 42 to 45 degrees F., and the frost-free period is 100 to 130 days.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the Couch and Lolak series. Couch soils lack a histic epipedon, aquic moisture conditions and have an argillic horizon. Lolak soils have a fine textured particle-size control section.
DRAINAGE AND PERMEABILITY: Poorly or very poorly drained; Very high surface runoff; Endosaturation is present with an apparent seasonal high water table between the soil surface and 20 inches (very shallow or shallow free water occurrence classes) from November through June. Cumulative annual duration classes are common or persistent. Permeability is very slow.
USE AND VEGETATION: Cuminvar soils are used for pasture, watershed and wildlife habitat. The native vegetation is mainly sedges and rushes.
DISTRIBUTION AND EXTENT: Eastern California, in the Surprise Valley, east of the Warner Mountains. These soils are not extensive. MLRA 23.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Davis, California.
SERIES ESTABLISHED: Modoc County (Surprise Valley Home Camp Area), California, 2006.
REMARKS: Diagnostic horizons and features recognized in this pedon are:
Histic epipedon - The zone from the soil surface to 8 inches (Oa horizon).
Aquic conditions - The conditions of endosaturation and reduction in horizons between the soil surface and 72 inches at certain times in normal years (Oa, C, 2Css1, 2Css2, 2Css3, 2Cgk1 and 2Cgk2 horizons).
Particle-size control section - The zone from 10 to 40 inches (lower C, 2Css1, 2Css2, 2Css3 and upper 2Cgk1 horizons).