LOCATION WATTERSON CA

Established Series
Rev. DV-ET-MAV-GAM
06/2017

WATTERSON SERIES

Watterson soils are very deep and well drained soils that formed in mixed alluvium influenced by volcanic ash and in some small areas granitic alluvium. Watterson soils are on alluvial fans and have slopes of 0 to 30 percent. The mean annual precipitation is about 250 mm, and the mean annual temperature is about 7 degrees C.

TAXONOMIC CLASS: Loamy-skeletal, mixed, superactive, mesic Pachic Haploxerolls

TYPICAL PEDON: Watterson sandy loam - on a slope of less than 1 percent at 2,105 meters elevation under big sagebrush, Douglas rabbitbrush and antelope bitterbrush vegetation. Colors are for dry soil unless otherwise stated. When described October 31, 1978, the soil was dry throughout. Ten percent of the soil surface is covered with fine and medium gravel.

A1--0 to 20 cm; brown (10YR 5/3) sandy loam, very dark grayish brown (10YR 3/2) moist; weak fine subangular blocky structure; soft, very friable, nonsticky and nonplastic; common very fine, few fine and medium roots; common very fine interstitial pores; 3 percent gravel; slightly acid (pH 6.1); clear wavy boundary. (13 to 25 cm thick)

A2--20 to 89 cm; brown (10YR 5/3) very gravelly sandy loam, dark brown (10YR 3/3) moist; weak fine angular blocky structure; hard, very friable, nonsticky and nonplastic; few fine and medium roots; common very fine interstitial pores; 35 percent gravel, and 15 percent cobbles; slightly acid (pH 6.1); abrupt smooth boundary. (50 to 75 cm thick)

2C--89 to 152 cm; light yellowish brown (2.5Y 6/4) sand, dark yellowish brown (10YR 4/4) moist; single grain; loose, nonsticky and nonplastic; few very fine roots; many fine interstitial pores; 2 percent gravel; neutral (pH 7.0).

TYPE LOCATION: Mono County, California. About 2 miles west of Crowley Lake and 4 miles east-northeast of Mammoth Airport; 200 feet north and 250 feet east of the southwest corner of section 33, T. 3 S., R. 29 E., USGS Whitmore Hot Springs 7.5 minute topographic quadrangle; latitude 37 degrees 38 minutes 15 seconds N and longitude 118 degrees 47 minutes 22 seconds W; WGS84 Decimal Degrees 37.6375000 latitude, -118.7894444 longitude.

RANGE IN CHARACTERISTICS: Depth of the soil is 150 cm or more. The particle-size control section averages 35 to 60 percent rock fragments, mainly gravel and cobbles. The soil between depths of 20 and 75 cm is usually dry from about May 30 to November 15, and is moist in some or all parts the rest of the time. Aridic moisture regime bordering on xeric. The soil temperature is above 5 degrees C. from about April 1 to December 20, and is above 8.3 degrees C. from about April 15 to November 30. The mean annual soil temperature is 8.3 to 14.4 degrees C. The soil reaction is slightly acid to neutral.

The A horizon color is 10YR 3/3, 4/2, 4/3, 5/3; or 5YR 5/3. Moist color is 10YR 3/2, 3/3; or 5YR 3/3. Textures are sandy loam, gravelly loamy sand, gravelly sandy loam and very gravelly sandy loam. Rock fragment content is 2 to 15 percent in the upper part and 35 to 60 percent in the lower part. Structure is weak subangular and angular blocky, single grain, or massive. The organic carbon content is 0.6 to 1.0 percent.

The C horizon color is 10YR 5/3, 5/4, 6/3; 2.5Y 6/4 or 5YR 5/3. Moist color is 10YR 4/3, 4/4; 2.5Y 4/4 or 5YR 3/3. Textures are sand, very gravelly sandy loam or very cobbly sand. Strata of loamy sand or gravelly sandy loam are present in some areas. Clay content averages 8 to 15 percent between 25 to 100 cm. Rock fragment content averages 35 to 60 percent consisting of 20 to 60 percent gravel and 5 to 20 percent cobbles. Some strata in the C horizon lack rock fragments. Structure is weak angular blocky, massive, or single grain. Stony substratum phases are recognized with textures of extremely stony loamy sand and sandy loam with 20 to 30 percent stones.

COMPETING SERIES: These are the Karoc and Wiskiflat series. Karoc soils have a mean annual soil temperature of 8.9 to 11.1 degrees C. and are neutral to slightly alkaline. The Wiskiflat soil has a mean annual soil temperature of 12.7 to 15 degrees C.

GEOGRAPHIC SETTING: Watterson soils are on alluvial fans and lake terraces. The parent material is mixed alluvium with volcanic ash and with much granitic influence. Some of the soils near the Sierran moraines may have formed in glacial outwash. Slopes range from 0 to 30 percent. The elevation ranges from 1,680 to 2,290 meters. The mean annual precipitation is 200 to 300 mm, and the mean annual temperature is 7.2 to 12.7 degrees C. The mean January temperature is about -2 degrees C.; the mean July temperature is about 19 degrees C. The frost-free season is about 105 to 140 days.

GEOGRAPHICALLY ASSOCIATED SOILS: These are the Buscones and Cashbaugh soils. Buscones soils are sandy and moderately deep over hard tuffaceous sandstone or conglomerate on hills and terraces. Cashbaugh soils are sandy and shallow over hard, tuffaceous sandstone or conglomerate on lake terraces.

DRAINAGE AND PERMEABILITY: Well drained; slow and medium runoff; moderately rapid over rapid permeability. In some pedons the permeability is moderately rapid. Irrigated soils are very poorly drained.

USE AND VEGETATION: Used for grazing and wildlife habitat. Vegetation is mainly big sagebrush, antelope bitterbrush, Indian ricegrass, and western needlegrass.

DISTRIBUTION AND EXTENT: East-central California. The soils are of small extent. MLRA 26.

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

SERIES PROPOSED: Mono County, California; Benton-Owens Valley Soil Survey, 1987.

REMARKS: Diagnostic horizons and features recognized in the profile are:

1. Mollic epipedon -- 0 to 89 cm (A1 and A2 horizons).

1.1 Color values meet mollic criteria. (10YR 5/3).

Other Soil Characteristics:

1. Lacks diagnostic subsoil horizons because:

1.1 No clay films, no segregated lime, no pedogenic structure.

2. The textural control section averages 35 to 60 percent rock fragments.

3. The soil moisture regime is aridic-xeric. It is dry for about 165 days and is above 5 degrees C. for about 260 days. It is dry greater than half the time the soil temperature is above 5 degrees C.

4. The soil temperature regime is on the cool end of mesic. M.A.S.T. is 8.3 to 14.4 degrees C. This is extrapolated from actual temperature transect data over the past years using Rod Arkley`s equation.

National Cooperative Soil Survey
U.S.A.