LOCATION FORTSAGE                CA

Established Series
Rev. SJB-DJE-JVC-GAM
03/2017

FORTSAGE SERIES

The Fortsage series consists of very deep, moderately well drained soils that formed in alluvium derived from mixed igneous rocks. Fortsage soils are on flood plains. Slopes are 0 to 2 percent. The mean annual precipitation is about 280 mm and the mean annual temperature is about 10 degrees C.

TAXONOMIC CLASS: Coarse-loamy, mixed, superactive, nonacid, mesic Oxyaquic Torrifluvents

TYPICAL PEDON: Fortsage silt loam--on a nearly level area of less than 1 percent slope under a cover of basin big sagebrush, annual grasses, and forbs at 1,300 meters elevation--rangeland. (Colors are for dry soil unless otherwise noted. When described on September 20, 1984, the soil was dry throughout.)

C1--0 to 5 cm; brown (10YR 5/3) silt loam, dark brown (10YR 3/3) moist; strong medium platy structure; soft, very friable, slightly sticky and slightly plastic; common medium roots; many very fine interstitial pores; few very thin strata; slightly effervescent; moderately alkaline (pH 8.0); abrupt smooth boundary. (3 to 25 cm thick)

C2--5 to 50 cm; pale brown (10YR 6/3) and light gray (10YR 7/2) highly stratified sand, silt loam, very fine sandy loam, and fine sandy loam, dark brown (10YR 3/3) and dark grayish brown (10YR 4/2) moist; loamy strata are massive and slightly hard, very friable, nonsticky and nonplastic; sandy strata are single grain, loose, nonsticky and nonplastic; common very fine, few fine and medium roots; many very fine interstitial pores; nine strata are present that are 1 to 4 inches thick; noneffervescent in matrix and slightly effervescent in finer textured strata; slightly alkaline (pH 7.5); abrupt smooth boundary. (25 to 75 cm thick)

C3--50 to 81 cm; pale brown (10YR 6/3) silt loam, dark brown (10YR 3/3) moist; massive; hard, friable, slightly sticky and slightly plastic; few very fine, fine and medium roots; many very fine tubular pores; fine stratification; few fine distinct dark yellowish brown (10YR 4/6) moist masses of iron accumulation; moderately alkaline (pH 8.0); clear smooth boundary. (8 to 50 cm thick)

Btnb--81 to 100 cm; pale brown (10YR 6/3) sandy clay loam, dark grayish brown (10YR 4/2) moist; moderate medium prismatic structure; hard, friable, slightly sticky and slightly plastic; many very fine roots on faces of peds; many very fine tubular pores; many distinct clay films and organic coats on faces of peds; slightly effervescent; moderately alkaline (pH 8.2); clear smooth boundary. (0 to 20 cm thick)

Bkb--100 to 152 cm; light brownish gray (2.5Y 6/2) stratified fine sandy loam and silt loam, dark grayish brown (2.5Y 4/2) moist; weak medium subangular blocky structure; slightly hard, very friable, slightly sticky and slightly plastic; few very fine roots; many very fine interstitial pores; secondary carbonates segregated in common fine threads; slightly effervescent; few fine distinct dark yellowish brown (10YR 4/4) moist masses of iron accumulation; moderately alkaline (pH 8.2).

TYPE LOCATION: Lassen County, California; in Long Valley about 0.6 miles southwest of the fence corner that is the southeast corner of the Lincoln Ranch and 50 feet north of the fence; approximately 4,000 feet south and 50 feet west of the northeast corner of section 21, T. 25 N., R. 17 E.; USGS Doyle 7.5 minute topographic quadrangle; 40 degrees 00 minutes 5.7 seconds north latitude and 120 degrees 04 minutes 18.7 seconds west longitude, WGS84 Decimal Degrees 40.0015833 latitude, -120.0718611 longitude.

RANGE IN CHARACTERISTICS:
Soil moisture - The soil moisture control section is dry in all parts from June 1 to November 15 (168 days). It is moist throughout from December 1 to April 1. The soil temperature exceeds 5.0 degrees C. from March 1 to December 15 (290 days). Within this time period, the moisture control section is moist in some part(s) from March 1 to June 1 and from November 15 to December 15 (123 days). The soil temperature exceeds 8.3 degrees C. from April 15 to November 15. Within this time period the moisture control section is moist in some part from April 15 to June 1 (15 days); Aridic (torric) moisture regime that borders on xeric.

Mean annual soil temperature - 10.6 to 11.7 degrees C.

Depth to redoximorphic features - 50 to 91 cm to redox concentrations of iron.

Particle-size control section - Clay content: Averages 8 to 15 percent.

Salinity (EC) - 0 to 2 mmhos/cm.

C1 horizon
Value: 5 through 7 dry, 3 through 5 moist; When the upper 7 inches of soil are mixed, the dry value is 6 or 7.
Chroma: 2 or 3 dry.
Texture: Silt loam or fine sandy loam.
Clay content: 5 to 15 percent.
Reaction: Neutral to moderately alkaline.
Other features: This horizon has rock structure as very thin strata and does not qualify as an ochric epipedon.

C2 and C3 horizons
Hue: 10YR or 2.5Y.
Value: 6 or 7 dry, 4 or 5 moist.
Chroma: 2 or 3 dry, 2 through 4 moist.
Texture: Stratified fine sandy loam to silt loam.
Clay content: 8 to 15 percent.
Reaction: Slightly alkaline or moderately alkaline.
Effervescence: Noneffervescent or slightly effervescent.

Btnb horizon (when present)
Texture: sandy clay loam or loam.
Clay content: 18 to 25 percent.
Reaction: Slightly alkaline or moderately alkaline.

Bkb horizon (when present)
Hue: 10YR or 2.5Y.
Value: 6 or 7 dry, 4 or 5 moist.
Chroma: 2 or 3 dry, 2 through 4 moist.
Texture: Stratified fine sandy loam to silt loam.
Clay content: 8 to 15 percent.
Reaction: Slightly alkaline or moderately alkaline.

COMPETING SERIES: This is the Fallon series. Fallon soils have mean annual soil temperature of 12to 14 degrees C.

GEOGRAPHIC SETTING: Fortsage soils are on flood plains. These soils formed in alluvium derived from mixed rocks. Slopes are 0 to 2 percent. Elevation ranges from 1,300 to 1,345 meters. The mean annual precipitation is 230 to 300 mm. The mean annual temperature is 9 to 11 degrees C. The mean January temperature is about -1 degrees C. and the mean July temperature is about 21 degrees C. The frost-free period is 100 to 120 days.

GEOGRAPHICALLY ASSOCIATED SOILS: These are the Honlak, Massack, Orr, and Yobe soils. Honlak soils are fine-loamy, have natric horizons, and are on stream terraces. Massack soils have thick mollic epipedons, are noncalcareous, and have endosaturation within 12 inches of the soil surface. Orr soils are fine-loamy, have argillic horizons, and occur on fan remnants. Yobe soils are on basin rims and are poorly drained.

DRAINAGE AND SATURATED HYDRAULIC CONDUCTIVITY: Moderately well drained; very low surface runoff; moderately rapid permeability; high saturated hydraulic conductivity. Endosaturation is present with an apparent seasonal high water table between 100 and 152 cm (deep free water occurrence class from January through April. Cumulative annual duration class is Common.
These soils are susceptible to frequent flooding for brief periods between January and April. Protected phases are recognized that are subject to rare flooding for brief periods year-round.

USE AND VEGETATION: Fortsage soils are used as rangeland. A few small protected areas are used for irrigated alfalfa and small grain crops. The present vegetation is mainly basin big sagebrush, annual and perennial grasses, and forbs.

DISTRIBUTION AND EXTENT: Northeastern California. These soils are not extensive with about 2,200 acres of the series mapped to date. MLRA 26.

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

SERIES ESTABLISHED: Lassen County (Susanville Area Soil Survey), California, 2000.

REMARKS: Diagnostic horizons and features recognized in this pedon are:
Ochric epipedon - The zone from the soil surface to 18 cm (C1 and part of the C2 horizons).
Endosaturation feature - The condition of ground water with an upper boundary between 100 and 152 cm during winter and spring in normal years (Bkb horizon).
Particle-size control section - The zone from 25 to 100 cm (C3 and Btnb horizons and parts of the C2 horizon).

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National Cooperative Soil Survey
U.S.A.