LOCATION FORGAY CA

Established Series
Rev. KJO/SJB/JJJ
01/2023

FORGAY SERIES

The Forgay series consists of very deep, somewhat excessively drained soils that formed in gravelly alluvium weathered from mixed rock sources. Forgay soils are on alluvial fans and stream terrraces. Slopes are 0 to 9 percent. The mean annual precipitation is about 38 inches and the mean annual temperature is about 50 degrees F.

TAXONOMIC CLASS: Loamy-skeletal, mixed, superactive, mesic Typic Dystroxerepts

TYPICAL PEDON: Forgay extremely gravelly coarse sandy loam on a smooth alluvial fan of 2 percent under medusahead and bottlebrush squirreltail (site is cleared of timber) at 3520 feet. (When described on September 27, 1982, the soil was moist between 0 to 15 inches and deeper than 36 inches, but dry from 15 to 36 inches. Colors are for dry soil unless otherwise stated.)

A--0 to 11 inches; light yellowish brown (10YR 6/4) extremely gravelly coarse sandy loam, brown (10YR 4/3) moist; weak thin and medium platy structure; slightly hard, very friable, nonsticky and nonplastic; common very fine roots; many very fine interstitial pores; 10 percent cobbles; 40 percent 5 to 75 mm gravel, 20 percent 2 to 5 mm gravel; slightly acid (pH 6.5); clear wavy boundary. (5 to 13 inches thick)

Bw1--11 to 28 inches; pale brown (10YR 6/3) extremely gravelly coarse sandy loam, brown (10YR 4/3) moist; weak fine angular blocky structure; soft, very friable, nonsticky and nonplastic; few very fine roots; many very fine interstitial pores and common fine tubular pores; 5 percent cobbles; 40 percent 5 to 75 mm gravel; 20 percent 2 to 5 mm gravel; slightly acid (pH 6.5); gradual wavy boundary. (6 to 17 inches thick)

Bw2--28 to 48 inches; light yellowish brown (10YR 6/4) very gravelly coarse sandy loam, brown (10YR 4/3) moist; weak fine and medium angular blocky structure; slightly hard, very friable, nonsticky and nonplastic; few very fine roots; many very fine interstitial pores and common very fine tubular pores; 30 percent 5 to 75 mm gravel; 20 percent 2 to 5 mm gravel; slightly acid (pH 6.1); clear wavy boundary. (20 to 25 inches thick)

C--48 to 60 inches; dark yellowish brown (10YR 4/4) moist; very gravelly sandy loam, single grain; loose, nonsticky and nonplastic; few very fine roots; many very fine interstitial pores; 30 percent 5 to 75 mm gravel; 20 percent 2 to 5 mm gravel; slightly acid (pH 6.1).

TYPE LOCATION: Plumas County, California; 20 feet W and 2400 feet N of the SE corner of section 19, T.24 N., R.10 E., MDBM.

RANGE IN CHARACTERISTICS: The mean annual soil temperature is about 48 degrees to 52 degrees F. The mean summer temperature is about 63 degrees to 65 degrees F. and the mean winter temperature is about 32 degrees to 34 degrees F. The soil moisture control section, (13 to 53 inches), is moist in all parts from about December 1 to May 15. It is dry in all parts from about July 15 to September 15. The soil temperature exceeds 41 degrees F. from about April 15 to November 15 and exceeds 47 degrees F. from about May 15 to November 1. Most undisturbed pedons have a surface litter decomposing pine needles and twigs about one inch thick. The reaction is slightly acid or neutral throughout. The 10 to 40 inch control section weighted average texture is coarse sandy loam or sandy loam with 40 to 80 percent gravel and cobbles.

The A horizon is 10YR 6/4, 6/2, 5/2, 5/3,or 4/2. Moist color is 10YR 4/3, 3/3, or 3/2. Where value is 4 or 5 dry and 3 moist and chroma is 2 dry and 2 or 3 moist, the A horizon is less than 6 inches thick. It is very gravelly sandy loam, extremely gravelly coarse sandy loam, or extremely gravelly loamy coarse sand. Rock fragments, mostly gravel, range from 35 to 75 percent.

The Bw horizon is 10YR 6/4, 6/3, 6/2, 5/4, or 5/3. Moist color is 10YR 4/4, 4/3, 4/2, 3/4, or 3/3. It is very gravelly sandy loam, extremely gravelly sandy loam, very gravelly coarse sandy loam, extremely gravelly loamy coarse sand or extremely gravelly coarse sandy loam. Rock fragments, mostly gravel, range from 40 to 80 percent.

COMPETING SERIES: There are no other soils in this family.

GEOGRAPHIC SETTING: Forgay soils are on alluvial fans and stream terraces. Slopes are 0 to 9 percent. The soil formed in gravelly alluvium weathered from mixed but dominately sedimentary rocks. Elevation is 3400 to 4600 feet. The climate is subhumid with warm dry summers and cold moist winters. The mean annual precipitation varies from 20 to 40 inches, some of which falls as snow. The mean annual temperature is about 50 degrees F. Mean July temperature is about 66 degrees F., and mean January temperature is about 34 degrees F. The average frost-free season is about 80 to 100 days.

GEOGRAPHICALLY ASSOCIATED SOILS: These are the Massack, Keddie and Plumas soils. Massack and Keddie soils are poorly drained, nonskeletal soils on stream terraces. Plumas soils have thick dark epipedons and are on toe slopes of fans.

DRAINAGE AND PERMEABILITY: Somewhat excessively drained; slow runoff; moderately rapid permeability. A moderately will drained wet phase, with a water table between the depths of 40 and 60 inches, occurs along the shore line of Lake Almanor. The water table is caused by fluctuating lake levels.

USE AND VEGETATION: Forgay soils are used for timber production and urban development. Vegetation is ponderosa pine, Jeffrey pine, douglas- fir, incense cedar, California black oak and open areas of bottlebrush squirreltail, medusahead, bluegrass, needlegrass and mountain brome.

DISTRIBUTION AND EXTENT: Northern California. The soils are not extensive.

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

SERIES ESTABLISHED: Plumas National Forest Area, California 1983.

REMARKS: Diagnostic horizons and features recognized in this pedon are:

Ochric epipedon: The zone from the mineral surface to 11 inches (A horizon) and a combined horizon zone from 11 to 48 inches (Bw horizon).

Last revised by the state on 1/88.

Series reclassified 7/98. Competing series not updated at that time.

National Cooperative Soil Survey
U.S.A.