LOCATION CONWAY                  CA

Established Series
Rev. HVB-ET-JJJ-MAV-JVC-GAM
03/2017

CONWAY SERIES

The Conway series consists of very deep, poorly drained soils that formed in alluvium derived from granitic and mixed sources influenced by volcanic ash. Conway soils are on flood plains and alluvial fans. Slopes are 0 to 15 percent. The mean annual precipitation is about 280 mm and the mean annual temperature is about 9.4 degrees C.

TAXONOMIC CLASS: Coarse-loamy, mixed, superactive, frigid Cumulic Endoaquolls

TYPICAL PEDON: Conway sandy loam--on a south-facing slope under sedges, tufted hairgrass, and Sandberg's bluegrass at 2,090 meters elevation--rangeland. (Colors are for dry soil unless otherwise noted. When described in August of 1988 the soil was moist throughout with a water table at 42 inches).

A1--0 to 10 cm; grayish brown (10YR 5/2) sandy loam, very dark grayish brown (10YR 3/2) moist; moderate fine and medium subangular blocky structure; slightly hard, very friable, slightly sticky and slightly plastic; many very fine and fine roots; many very fine and fine tubular and interstitial pores; 5 percent gravel; slightly acid (pH 6.2); abrupt smooth boundary.

A2--10 to 30 cm; grayish brown (10YR 5/2) gravelly sandy loam, very dark brown (10YR 2/2) moist; moderate fine subangular blocky structure; slightly hard, friable, slightly sticky and slightly plastic; many very fine and fine and common medium roots; many very fine, fine and medium interstitial and common very fine tubular pores; 15 percent gravel; neutral (pH 6.7); clear wavy boundary.

A3--30 to 71 cm; grayish brown (10YR 5/2) gravelly sandy loam, very dark brown (10YR 2/2) moist; moderate fine and medium subangular blocky structure; slightly hard, friable, slightly sticky and slightly plastic; many very fine and fine and few medium roots; many very fine and fine interstitial and common very fine tubular pores; few fine distinct dark yellowish brown (10YR 4/4) masses of iron accumulation lining roots and pores; 15 percent gravel; neutral (pH 6.8); clear wavy boundary.

C--71 to 107 cm; light brownish gray (10YR 6/2) gravelly sandy loam, olive gray (5Y 4/2) moist; massive; slightly hard, friable, slightly sticky and slightly plastic; common very fine and fine roots; many very fine and fine interstitial and common very fine tubular pores; 20 percent gravel; neutral (pH 6.6); abrupt wavy boundary.

Cg--107 to 152 cm; white (5Y 8/1) gravelly coarse sandy loam, greenish gray (5GY 5/1) moist; massive; slightly hard, very friable, nonsticky and nonplastic; few very fine roots; many fine and medium interstitial pores; common medium prominent dark yellowish brown (10YR 4/4) masses of iron accumulation; 25 percent gravel; slightly alkaline (pH 7.6).

TYPE LOCATION: Mono County, California; about 0.25 mile southwest of Conway Ranch; about 530 feet east and 530 feet south of the northwest corner of section 6, T. 2 N., R. 26 E.; USGS Lundy 7.5 minute topographic quadrangle; latitude 38 degrees 4 minutes 3 seconds N and longitude 119 degrees 9 minutes 27 seconds W; WGS84 Decimal Degrees 38.0675000 latitude, -119.1575000 longitude.

RANGE IN CHARACTERISTICS:

Soil moisture - The soil between a depth of 25 and 84 cm is usually dry between about August 15 and November 15 and is moist in some or all parts the rest of the time. The soil temperature is above 5.0 degrees C. from about April 15 to November 30, and is above 8.3 degrees C. from about May 15 to October 30. A high water table is present at a depth of 0 to 122 cm but is typically above 30 cm at some time of the year during the growing season.

Mean annual soil temperature - 6.7 to 8.3 degrees C. High water table levels contribute to a lower mean annual soil temperature than geographically associated soils.

Mollic epipedon thickness - 60 to 100 cm.

Particle-size control section - Clay content: Averages 10 to 18 percent; Rock fragments: Averages 15 to 30 percent, mainly gravel. Lithology of fragments are granite and volcanic rocks such as rhyolite; Volcanic glass content: Estimated at 5 to 15 percent glass in coarse silt through very coarse sand fractions with oxalate extractable aluminum plus one-half iron contents of less than 0.2 percent.

A horizons
Dry color: 10YR 3/3, 4/2, or 5/2.
Moist color: 10YR 2/2 or 3/2.
Texture: Sandy loam, very fine sandy loam, loam, gravelly sandy loam, or cobbly sandy loam.
Rock fragments: 0 to 25 percent gravel, 0 to 20 percent cobbles.
Reaction: Slightly acid to moderately alkaline in the A1 horizon, neutral to moderately alkaline in the A2 and A3 horizons.
Organic matter content: 2 to 4 percent.
Redoximorphic features: Few or common, distinct or prominent masses of iron accumulation.

C and Cg horizons
Dry color: 10YR 5/2, 6/2, 7/1; 2.5Y 6/2; 5Y 7/1, or 8/1. Moist color: 10YR 4/2; 2.5Y 4/2; 5Y 4/2 or 5GY 5/1.
Texture: Gravelly sandy loam, gravelly coarse sandy loam, or cobbly coarse sandy loam; strata of loamy sand to very cobbly loamy sand are common.
Rock fragments: 10 to 30 percent, mainly gravel.
Reaction: Neutral to moderately alkaline.
Redoximorphic features: Common or many masses of iron accumulation; redox depletion of iron is evident as the low chroma matrix in gleyed subhorizons.
Other features: Cobbly substratum phases are recognized with 35 to 60 percent rock fragments, 15 to 25 percent of which are cobbles. Texture of very cobbly coarse sandy loam occurs in such phases at depths below 40 inches.

COMPETING SERIES: These are the Chaffee, Sanpoil, and Schrader series.

Chaffee soils have sandy-skeletal horizons below 40 inches and do not have volcanic glass in the particle-size control section. Sanpoil soils average less than 15 percent rock fragments in the particle-size control section and are not dry between August 15 and November 15. Schrader soils average 0 to 15 percent rock fragments and do not have volcanic glass in the particle-size control section.

GEOGRAPHIC SETTING: Conway soils are on flood plains and alluvial fans and they are associated with springs, seeps, and riparian water courses. These soils formed in alluvium derived from granitic and mixed sources influenced by volcanic ash. Slopes are 0 to 15 percent. Elevation ranges from 6,000 to 8,600 feet. The mean annual precipitation is 8 to 16 inches, much of it as snow. The mean annual temperature is 43 to 54 degrees F. The frost-free period is 70 to 150 days.

GEOGRAPHICALLY ASSOCIATED SOILS: These are the Watterson and Alamedawell soils.

DRAINAGE AND SATURATED HYDRAULIC CONDUCTIVITY: Poorly drained; very low or low surface runoff; moderately rapid permeability; high saturated hydraulic conductivity. Endosaturation is present with an apparent seasonal high water table between 15 and 120 cm (very shallow to deep free water occurrence classes) year-round but it is above 60 cm in spring. Cumulative annual duration class is Permanent. These soils are susceptible to occasional flooding for brief periods between January and June.

USE AND VEGETATION: Conway soils are used for pasture and wetland wildlife habitat. The vegetation is mainly sedges, tufted hairgrass, and Sandberg's bluegrass.

DISTRIBUTION AND EXTENT: East-central California. These soils are not extensive with about 5,000 acres of the series mapped to date. MLRA 26.

MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Davis, California.

SERIES ESTABLISHED: Mono County, California, Benton-Owens Valley Area, 1997.

REMARKS: Diagnostic horizons and features recognized in this pedon are:
Mollic epipedon - The zone from the soil surface to 71 cm (A1, A2, and A3 horizons).
Aquic conditions - The conditions of endosaturation, reduction, and redoximorphic features between 30 and 152 cm at certain times during normal years (parts of the A3, C, and Cg horizons).
Particle-size control section - The zone from 25 to 100 cm (A3 horizon and parts of the A2 and C horizons).

---

National Cooperative Soil Survey
U.S.A.