LOCATION GREENHORN CAEstablished Series
TAXONOMIC CLASS: Coarse-loamy, mixed, superactive, nonacid, mesic Aquic Xerofluvents
TYPICAL PEDON: Greenhorn loam - on a slope of less than 1 percent in an irrigated pasture at about 3,400 feet elevation. (When described September 27, 1982 the soil was moist from 0 to 3 inches, dry from 3 to 27 inches and moist from 27 to 73 inches. Colors are for dry soil unless otherwise stated.)
Ap--0 to 7 inches; light yellowish brown (10YR 6/4) loam, dark brown (10YR 3/3) moist; moderate very fine, fine and medium subangular blocky structure; slightly hard, very friable, slightly sticky and slightly plastic; many very fine and fine and common medium roots; many very fine interstitial pores; slightly acid (pH 6.1); clear wavy boundary. (4 to 9 inches thick)
A--7 to 11 inches; light yellowish brown (10YR 6/4) fine sandy loam, dark brown (10YR 3/3) moist; weak very fine and fine subangular blocky structure; slightly hard, very friable, slightly sticky and slightly plastic; many very fine, common fine and few medium roots; common very fine tubular pores; slightly acid (pH 6.5); clear wavy boundary. (0 to 5 inches thick)
C--11 to 16 inches; very pale brown (10YR 7/4) loam, dark brown (10YR 4/3) moist; common fine distinct strong brown (7.5YR 5/6) mottles (10YR 4/6) moist; weak very thick platy structure; hard, very friable, slightly sticky and slightly plastic; many very fine, common fine and few medium roots; common very fine tubular pores; slightly acid (pH 6.5); clear wavy boundary. (5 to 13 inches thick)
Cc1--16 to 27 inches; light brownish gray (2.5Y 6/2) and light yellowish brown (10YR 6/4) stratified fine sandy loam and fine sand, olive brown (2.5Y 4/4) moist and brown (10YR 4/3) moist; many fine and medium distinct strong brown (7.5YR 5/6) mottles and common fine and medium very dark grayish brown (10YR 3/2) mottles, strong brown (7.5YR 4/6) moist and dark reddish brown (5YR 2.5/2) moist; weak very thick platy structure; slightly hard and soft, very friable, slightly sticky and nonsticky and slightly plastic and nonplastic; common very fine and fine and few medium roots; common very fine and fine and few medium tubular pores; 5 percent dark reddish brown (2.5YR 3/4) moist, firm, 5 to 10 mm iron segregations in old root channels; slightly acid (pH 6.5); abrupt smooth boundary. (8 to 19 inches thick)
Cc2--27 to 39 inches; light yellowish brown (10YR 6/4) and pale yellow (2.5Y 7/4) stratified loam, fine sandy loam and fine sand, dark yellowish brown (10YR 4/4) moist and olive brown (2.5Y 4/4) moist; many fine and medium distinct strong brown (7.5YR 5/6) mottles and common fine and medium very dark grayish brown (10YR 3/2) mottles, strong brown (7.5YR 4/6) moist and dark reddish brown (5YR 2.5/2) moist; massive; slightly hard, very friable, slightly sticky and nonsticky and slightly plastic and nonplastic; few very fine and fine roots; common very fine tubular and interstitial pores; 5 percent dark reddish brown (2.5YR 3/4) moist, firm, 5 to 10 mm iron segregations in old root channels; neutral (pH 7.0); clear wavy boundary. (9 to 18 inches thick)
2Acb--39 to 73 inches; gray (10YR 5/1), yellowish brown (10YR 5/4) and grayish brown (10YR 5/2) stratified loam, black (10YR 2/1) moist, dark brown (10YR 3/3) moist and very dark grayish brown (10YR 3/2) moist; many fine and medium prominent red (2.5YR 5/6) mottles and many medium and large distinct strong brown (7.5YR 5/6) mottles, red (2.5YR 4/6) moist and dark brown (7.5YR 3/4) moist; massive; hard, very friable, slightly sticky and slightly plastic few very fine roots; few very fine tubular pores; 1 percent dark reddish brown (2.5YR 3/4) moist, firm, 5 to 10 mm iron segregations in old root channels; horizon has thin strata of pale yellow (5Y 7/3) loam, olive (5Y 5/3) moist; neutral (pH 7.0).
TYPE LOCATION: Plumas County, California; about 0.4 mile north of Quincy on Highway 89, 2,000 feet east of Highway 89 through the Ford dealer's parking lot and also 200 feet east of Clear Stream Channel and 100 feet south of the south boundary fence line of the Gansner Airport; about 2,750 feet north and 1,900 feet east of the southwest corner of section 14, T. 24 N., R. 9 E.
RANGE IN CHARACTERISTICS: The mean annual soil temperature varies from 47 degrees to 50 degrees F. The mean winter soil temperature varies from 34 degrees to 36 degrees F. The mean summer soil temperature varies from 60 degrees to 62 degrees F. The soil temperature exceeds 41 degrees F. from about May 1 to December 1. These soils are usually saturated during the late winter and spring due to a seasonal water table at a depth of 20 to 40 inches. These soils are highly stratified and include textures of silt loam, loam, very fine sandy loam, fine sandy loam, sandy loam, sand and fine sand. The 10 to 40 inch control section when mixed is sandy loam or loam with a weighted average clay content of 8 to 15 percent and 50 to 60 percent sand. Depth to mottles is 0 to 11 inches. Depth to buried A horizons is 26 to 50 inches. One or more Ab horizons are present. Iron segreations, 2 to 15 mm in diameter, range from 1 to 5 percent by volume.
The A horizon is 10YR 5/3, 5/4, 6/3 or 6/4. Moist color is 10YR 3/2, 3/3, 4/3 or 4/4. Horizons with dry color of 10YR 5/3 and moist color of 10YR 3/2 are less than 4 inches thick and are at a depth of less than 10 inches. Texture is loam or fine sandy loam.
In the 10 to 30 inch part, 80 percent or more of the matrix has dry color of 10YR 5/4, 6/4, 7/4; 2.5Y 6/2 or 7/4. Moist color is 10YR 3/3, 4/2, 4/3, 4/4; 2.5Y 4/2 or 4/4. Twenty percent or less of the 10 to 30 inch part has moist color of 10YR 2/1, 2/2 or N2/.
Below a depth of 30 inches, dry color is 10YR 5/1, 5/2, 5/4, 6/4; 2.5Y 7/2 or 7/4. Moist color is 10YR 2/1, 3/1, 3/2, 3/3, 4/3, 4/4; 2.5Y 4/4; 5Y 2.5/1, 2.5/2, 3/2, 4/2, 4/3 or N2/. Reaction is slightly acid or neutral.
COMPETING SERIES: These are the Fallon soils. The Fallon soils are arid with 4 to 6 inches precipitation.
GEOGRAPHIC SETTING: Greenhorn soils are on flood plains. Elevation is 3,400 to 3,500 feet. These soils formed in mixed alluvium weathered mostly from metasedimentary rocks. Most of the areas mapped are forming in material deposited downstream from hydraulic mining operations conducted in the 1860s and 1870s. The climate is subhumid with warm dry summers and cool moist winters. Mean annual precipitation is about 35 inches. Mean January temperature is about 34 degrees F., mean July temperature is about 66 degrees F. and the mean annual temperature is about 50 degrees F. Frost-free season is 80 to 100 days.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the Gansner, Keddie and Massack soils. All of these soils have mollic epipedons. In addition, the Gansner soils have 27 to 35 percent clay in the control section and the Keddie soils have 18 to 27 percent clay in the control section.
DRAINAGE AND PERMEABILITY: Poorly drained; slow runoff; moderate permeability. A seasonal high water table is at a depth of 20 to 40 inches at some time from December to June. Flooding is occasional for brief periods from December through March.
USE AND VEGETATION: Used mainly for pasture with some small areas cut for grass hay. The vegetation is mainly pasture species of timothy, fescue, redtop, clover and other grasses and forbs.
DISTRIBUTION AND EXTENT: Western Plumas County, California in American and Indian Valleys. These soils are not extensive.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Davis, California
SERIES ESTABLISHED: Plumas National Forest Area, California 1984.
OSED scanned by SSQA. Last revised by state on 4/84.
REMARKS:
The superactive cation exchange activity class was added in 03/2003 to the taxonomic classification by the National Soil Survey Center on request of the Reno MLRA office, without review of the soil series property data. The remainder of this document has not been updated.