LOCATION CUMMINGS CAEstablished Series
TAXONOMIC CLASS: Ashy, glassy, calcareous, frigid Aquandic Endoaquolls
TYPICAL PEDON: Cummings mucky ashy silty clay loam - cultivated. (Colors are for dry soil unless otherwise noted).
Ap--0 to 6 inches; very dark gray (10YR 3/1) mucky ashy silty clay loam, black (10YR 2/1) moist; moderate medium subangular blocky structure; hard, very friable, moderately sticky and moderately plastic; many very fine roots; many very fine tubular pores; many 2 to 5 millimeter white (N 8/) freshwater snail and clam shells; strongly effervescent; strongly alkaline (pH 8.6); abrupt wavy boundary. (5 to 8 inches thick)
A2--6 to 10 inches; very dark gray (10YR 3/1) ashy silty clay loam, black (10YR 2/1) moist; strong fine and medium subangular blocky structure; hard, very friable, moderately sticky and moderately plastic; many very fine roots; many very fine and common fine tubular pores; many 2 to 5 millimeter white (N 8/) freshwater snail and clam shells; strongly effervescent; strongly alkaline (pH 8.6); clear wavy boundary. (4 to 12 inches thick)
A3--10 to 18 inches; dark gray (10YR 4/1) ashy silty clay loam, black (10YR 2/1) moist; strong medium prismatic structure parting to strong fine and medium subangular blocky; hard, very friable, moderately sticky and moderately plastic; many very fine roots; many very fine and fine tubular pores; many 2 to 5 millimeter white (N 8/) freshwater snail shells; common fine distinct very dark gray (N 3/) organic stains; strongly effervescent; strongly alkaline (pH 8.6); clear wavy boundary. (6 to 12 inches thick)
ABk--18 to 28 inches; gray (10YR 5/1) ashy silty clay loam, very dark gray (10YR 3/1) moist; strong medium prismatic structure parting to fine and medium subangular blocky; hard, very friable, moderately sticky and moderately plastic; many very fine roots; common very fine and few fine tubular, pores; common 2 to 5 millimeter distinct black (N 2.5/) organic stains and common prominent white (N 8/) lime segregations and 2 to 5 millimeter freshwater snail shells; strongly effervescent; strongly alkaline (pH 8.6); abrupt smooth boundary. (5 to 15 inches thick)
ABky--28 to 34 inches; dark gray (10YR 4/1) ashy silty clay loam, black (10YR 2/1) crushed moist; strong medium and coarse subangular blocky structure; hard, firm, moderately stick and moderately plastic; few very fine roots; common very fine tubular pores; common (2 percent) fine and medium distinct white (N 8/) soft masses of lime and few (0.5 percent) fine distinct white (N 8/) soft masses of gypsum; few 2 to 5 millimeter freshwater snail shells, few fine and medium faint brown (10YR 4/3) redox iron concentrations, and few fine distinct very dark gray (10YR 3/1) organic stains; strongly effervescent; moderately alkaline (pH 8.2); clear wavy boundary. (4 to 10 inches thick)
ABk--34 to 44 inches; black (10YR 2/1) and dark gray (10YR 4/1) ashy silty clay loam, black (N 2.5/)moist; moderate medium and coarse subangular blocky structure; hard, very friable, moderately sticky and moderately plastic; common very fine tubular pores; many very fine roots; 2 percent 2 to 5 millimeter prominent white (N 8/) soft masses of lime; few 2 to 5 millimeter distinct very dark gray (10YR 3/1) organic stains; slightly effervescent; moderately alkaline (pH 8.0); clear wavy boundary. (4 to 12 inches thick)
C--44 to 63 inches; 80 percent brownish yellow (10YR 6/8) and 10 percent pale brown (10YR 6/3) ashy silty clay loam, dark yellowish brown (10YR 4/6) moist and brown (10YR 4/3) moist; massive; hard, very friable, moderately stick and moderately plastic; few very fine roots; common very fine tubular pores; noneffervescent; 25 percent 1 to 2 millimeter dark gray (10YR 4/1) redox depletions, black (N 2.5/) moist; moderately alkaline (pH 8.0).
TYPE LOCATION: Modoc County, California; north of Surprise Valley and near the south end of Cow Head Lake; approximately 1200 feet east and 150 feet south of the projected northwest corner of section 33, T. 47 N., R. 17 E. USGS Lake Annie 7.5 minute topographic quadrangle; 41 degrees 54 minutes 25.9 seconds north latitude and 120 degrees 01 minutes 45.3 seconds west longitude, NAD27.
RANGE IN CHARACTERISTICS:
Soil moisture - Moist or wet in winter and spring, ponded for long or very long duration in spring and early summer, dry mid-to-late summer and fall.
Aquic conditions - Saturated within a depth of 12 inches in spring and early summer.
Mean annual soil temperature - 43 to 47 degrees F.
Mean summer soil temperature - 60 to 63 degrees F.
Oxalate Al + 1/2 oxalate iron: 0.2 to 0.4 percent.
Volcanic glass content - 50 to 80 percent in the coarse silt through fine sand fractions.
Mollic epipedon thickness - 24 to 48 inches.
Particle-size control section - Clay content: averages 27 to 35 percent (field estimated).
Reaction Moderately alkaline to strongly alkaline.
A horizons - Hue: 10YR, 2.5Y or N.
Value: 3 through 5 dry, 2 or 3 moist.
Chroma: 0 or 1, dry or moist.
Effervescence: Strongly effervescent or violently effervescent.
AB horizons - Hue: 10YR, 2.5Y or N.
Value: 3 through 5 dry, 2 or 3 moist.
Chroma: 0 or 1, dry or moist.
Texture: ashy silty clay loam; strata of ashy silt loam, silty clay or clay are in some pedons.
Gypsum: Subhorizons with few soft masses of gypsum are in some pedons.
Carbonates: Few or common soft masses or filaments of lime.
Calcium carbonate equivalent: Up to 5 percent in any subhorizon.
Effervescence: Slightly effervescent or strongly effervescent.
C horizon - Hue: 10YR, 2.5Y or N.
Value: 6 or 7 dry, 4 through 6 moist.
Chroma: 1 through 8.
Structure: Weak subangular blocky or is massive.
Effervescense: Noneffervescent through strongly effervescent.
COMPETING SERIES: These are the Bridgewell (T)(OR) and Hussa series. Bridgewell soils have horizons with visible pumiceous ash grains and have a mollic epipedon that is 12 to 20 inches thick. Hussa has a mollic epipedon 12 to 24 inches thick.
GEOGRAPHIC SETTING: Cummings soils are on lake terraces and floodplains. Slopes range from 0 to 2 percent, but slopes less than 1 percent are most typical. They formed in lacustrine sediments that were derived primarily from volcanic ash and tuff with admixtures from andesite and basalt. Elevations range from 5,000 to 5,500 feet. The climate is cold, continental with mean annual precipitation of about 12 to 16 inches. The mean annual air temperature is about 40 to 44 degrees F. The frost-free period is about 70 to 100 days.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the Couch, Jesayno, Nevadash and Weimer series. Couch soils have ochric epipedons and clay Bt horizons. Jesayno soils have ochric epipedons and are well drained. Nevadash soils are well drained. Weimer soils have clay control sections that contain slickensides.
DRAINAGE AND PERMEABILITY: Poorly drained. These soils were developed under very poorly drained conditions but the drainage has been improved by providing an outlet for Cow Head Lake and a protective dike to divert runoff waters. The water table is normally about 12 inches below the soil surface during the spring months and drops during the summer months. Surface runoff is negligible or very low during years of normal or heavy runoff when the water may stand on the soil surface for as long as 4 to 6 months. Seasonal flooding occurs on some phases of this soil. Drainage ditches and pumping has reduced the ponding and lowered the water table. Permeability is moderately slow.
USE AND VEGETATION: These soils are used for dryland production of small grains and pasture. The native vegetation in undisturbed areas is mat muhly and other perennial grasses.
DISTRIBUTION AND EXTENT: These soils occur in high elevation basins in northeastern California where they are inextensive. MLRA 23.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Davis, California.
SERIES ESTABLISHED: Surprise Valley-Home Camp Area, Modoc and Lassen Counties, California and Washoe County, Nevada, 1971. The name is from Cummings Lake, located near the type location.
REMARKS: The type location was moved to another location in the same delineation after an unsuccessful attempt to recover the type location during the update. The revision of February 2003 updates the taxonomic class from Medial, frigid Thaptic Endoaquands.
Original author initials include: LNL-LWW-SBJ-JVC