LOCATION EAST FORK NV

Established Series
Rev. LNL-GJS-JVC-JBF
05/2016

EAST FORK SERIES

The East Fork series consists of very deep, moderately well drained soils that formed in alluvium derived from mixed rocks. East Fork soils are on flood plains and low stream terraces. Slopes are 0 to 2 percent. The mean annual precipitation is about 125 mm and the mean annual temperature is about 12 degrees C.

TAXONOMIC CLASS: Fine-loamy, mixed, superactive, mesic Oxyaquic Haploxerolls

TYPICAL PEDON: East Fork clay loam--irrigated pasture. (Colors are for dry soil unless otherwise noted.)

Ap--0 to 15 cm; grayish brown (10YR 5/2) clay loam, very dark grayish brown (10YR 3/2) moist; moderate medium subangular blocky structure parting to moderate coarse granular; slightly hard, friable, moderately sticky and moderately plastic; many very fine, many fine, and many medium roots; common fine tubular and many fine interstitial pores; moderately alkaline (pH 8.1); clear smooth boundary. (10 to 25 cm thick)

ABk--15 to 36 cm; grayish brown (10YR 5/2) loam, very dark grayish brown (10YR 3/2) moist; moderate medium and fine granular structure; slightly hard, friable, moderately sticky and moderately plastic; many very fine, many fine, and common medium roots; common fine, common medium, and few coarse tubular pores; common earthworm casts; secondary carbonates segregated in few fine light gray (10YR 7/2) masses; noneffervescent in matrix and slightly effervescent on masses; moderately alkaline (pH 8.3); clear wavy boundary. (15 to 25 cm thick)

Bk--36 to 69 cm; grayish brown (10YR 5/2) clay loam, dark grayish brown (10YR 4/2) moist; weak medium and fine subangular blocky structure; slightly hard, friable, moderately sticky and moderately plastic; common fine and medium roots; common fine and medium tubular pores; secondary carbonates segregated in common fine light gray (10YR 7/2) masses; noneffervescent in matrix and slightly effervescent on masses; few fine faint dark brown (7.5YR 3/2) moist masses of iron accumulation; strongly alkaline (pH 9.0); clear wavy boundary. (25 to 38 cm thick)

C1--69 to 91 cm; grayish brown (10YR 5/2) clay loam, dark grayish brown (10YR 4/2) moist; weak fine subangular blocky structure; slightly hard, friable, moderately sticky and moderately plastic; few fine and medium roots; few fine and medium tubular pores; many medium faint dark brown (7.5YR 3/2) moist, masses of iron accumulation; few fine faint black (10YR 2/1) moist masses of humified organic matter; strongly alkaline (pH 8.6); gradual smooth boundary.

C2--91 to 152 cm; grayish brown (10YR 5/2) clay loam, dark grayish brown (10YR 4/2) moist; weak fine subangular blocky structure; slightly hard, friable, moderately sticky and moderately plastic; few fine and medium roots; few fine and medium tubular pores; many medium faint dark brown (7.5YR 3/2) moist, masses of iron accumulation; few fine faint black (10YR 2/1) moist masses of humified organic matter; moderately alkaline (pH 8.4). (Combined thickness of the C horizons is more than 76 cm)

TYPE LOCATION: Churchill County, Nevada; in the Lahontan Valley about 0.75 mile north-northeast of the intersection of U.S. Highways 50 and 95 in Fallon; approximately 1,390 feet south and 1,685 feet west of the northeast corner of section 30, T. 19 N., R. 29 E.; USGS Fallon 7.5 minute topographic quadrangle; latitude 39 degrees 29 minutes 8.1 seconds N and longitude 118 degrees 46 minutes 7.9 seconds W; WGS84 Decimal Degrees 39.4855833 latitude, -118.768861 longitude..

RANGE IN CHARACTERISTICS:
Soil moisture: Usually dry unless irrigated; under natural conditions these soils are moist in the moisture control section in winter and early spring, dry in late spring through fall; aridic soil moisture regime that borders on xeric.
Mean annual soil temperature: 12 to 14 degrees C.
Mollic epipedon thickness: 25 to 50 cm.
Depth to horizons with identifiable secondary carbonates: 15 to 91 cm.
Salinity (EC): 0 to 32 mmhos/cm.
Sodicity (SAR): 1 to 45.
Other features: Organic matter decreases irregularly with depth and one or more buried A horizons are common in some pedons; gravelly material is at a depth of 107 cm or more in some pedons.

Particle-size control section - Clay content: Averages 25 to 35 percent.
Rock fragments: Averages less than 5 percent.

Ap and ABk horizons
Value: 4 or 5 dry.
Chroma: 2 or 3, dry or moist.
Reaction: Slightly alkaline through strongly alkaline.
Organic matter content: 1 to 3 percent.
Calcium carbonate equivalent: 0 to 2 percent.

Bk horizon
Value: 5 through 7 dry, 3 through 5 moist.
Chroma: 2 or 3, dry or moist.
Texture: Clay loam, loam, or sandy clay loam.
Clay content: Averages 25 to 35 percent.
Rock fragments: 0 to 5 percent gravel.
Reaction: Moderately alkaline or strongly alkaline.
Identifiable secondary carbonates: Occurs as few fine or medium masses.
Calcium carbonate equivalent: 1 to 3 percent.
Redoximorphic features: Redox concentrations occur as masses of iron accumulation.

C or Ck horizons
Hue: 10YR or 2.5Y.
Value: 5 or 6 dry, 4 or 5 moist.
Chroma: 2 through 4, dry or moist.
Texture: Dominantly clay loam, sandy clay loam, or silty clay loam; some highly stratified pedons range from sand to clay.
Clay content: 25 to 35 percent.
Rock fragments: 0 to 5 percent gravel.
Reaction: Slightly alkaline to strongly alkaline.
Identifiable secondary carbonates: Occurs in some pedons as few fine or medium masses.
Calcium carbonate equivalent: 0 to 3 percent.
Redoximorphic features: Redox concentrations occur as masses of iron accumulation.

COMPETING SERIES: This is the Settledran series. Settledran soils have mean annual soil temperature of 9 to 12 degrees C.

GEOGRAPHIC SETTING: East Fork soils are on flood plains and low stream terraces. They formed in alluvium derived from mixed rocks. Slopes are 0 to 2 percent. Elevations range from 1,189 to 1,463 meters. The climate is arid with cool, moist winters and hot, dry summers. The mean annual precipitation is 100 to 200 mm, the mean annual temperature is 11 to 13 degrees C, and the frost-free period is 110 to 140 days.

GEOGRAPHICALLY ASSOCIATED SOILS: These are the Dia, Dithod, and Sagouspe soils. Dia soils are fine-loamy over sandy or sandy-skeletal. Dithod soils are coarse-loamy. Sagouspe soils are sandy and have ochric epipedons.

DRAINAGE AND SATURATED HYDRAULIC CONDUCTIVITY: Moderately well drained and moderately high saturated hydraulic conductivity. Endosaturation is present with an apparent seasonal high water table between 90 and 150 cm(moderately deep and deep free water occurrence classes) from December through August. Cumulative annual duration classes are Common or Persistent. These soils are susceptible to rare flooding for brief periods or occasional flooding for long periods between December and June.

USE AND VEGETATION: East Fork soils are used for irrigated cropland, wildlife habitat, and some livestock grazing. Alfalfa, small grains, and grass-legume pastures are the principal crops. The vegetation in rangeland is mainly basin big sagebrush and basin wildrye. Saline-sodic areas have black greasewood and inland saltgrass.

DISTRIBUTION AND EXTENT: Western Nevada. These soils are moderately extensive. MLRA 27.

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

SERIES ESTABLISHED: Douglas County (Physical Survey of the Carson Valley SCD), Nevada, 1940.

REMARKS: Diagnostic horizons and features recognized in this pedon are:
Mollic epipedon - The zone from the soil surface to 36 cm (Ap and ABk horizons).
Identifiable secondary carbonates - The zone from 15 to 69 cm (ABk and Bk horizons).
Endosaturation feature - The condition of ground water with an upper boundary between 91 and 152 cm at certain times during normal years (C2 horizon).
Particle-size control section - The zone from 25 to 100 cm (Bk and C1 horizons and parts of the ABk and C2 horizons).

The revision of March 2000 moved the type location from Douglas County to a more representative area in Churchill County. It also restricted the series concept to the warmer, drier portion of the climate range within MLRA 27 and updated the subgroup from fluvaquentic to oxyaquic.

ADDITIONAL DATA: The typical pedon at the series type location was sampled in 1959 and characterized by the soil survey laboratory in Riverside, CA as pedon 59NV001003 (pedon # 40A3247). The data are published in Soil Survey Investigations Report No. 23 on page 209. Another pedon has full characterization data by the Soil Survey Laboratory (SSL), Lincoln, NE as user pedon ID 99NV001005 (pedon # 00P0243).

National Cooperative Soil Survey
U.S.A.