LOCATION ESRO CAEstablished Series
TAXONOMIC CLASS: Fine-silty, mixed, superactive, frigid Aquandic Endoaquolls
TYPICAL PEDON: Esro silt loam - on a slope of 2 percent under tufted hairgrass and northern mannagrass at 5,000 feet elevation. (Colors are for dry soil unless otherwise noted. When described July 8, 1966, the soil was moist to 32 inches and saturated below.)
A1--0 to 7 inches; dark gray (10YR 4/1) silt loam, black (N 2/0) moist; moderate medium platy structure; slightly hard, friable, sticky and plastic; many very fine and fine roots; few fine tubular pores; neutral (pH 6.8); abrupt smooth boundary. (5 to 10 inches thick)
A2--7 to 14 inches; gray (N 5/0) silt loam, black (N 2/0) moist; moderate medium prismatic structure that parts to moderate medium subangular blocky; hard, friable, very sticky and plastic; many fine and common medium roots; common very fine and few fine tubular pores; neutral (pH 7.0); abrupt smooth boundary. (5 to 12 inches thick)
A3--14 to 32 inches; gray (10YR 5/1) silt loam, very dark grayish brown (10YR 3/2) moist; moderate medium prismatic structure; hard, slightly firm, very sticky and very plastic; few fine and many medium roots; common very fine, medium and few fine tubular pores; neutral (pH 7.0); abrupt wavy boundary. (12 to 28 inches thick)
Bg--32 to 43 inches; variegated gray (10YR 5/1 and 6/1) silt loam, dark grayish brown (10YR 4/2) moist; common fine distinct light olive gray (5Y 6/2), olive gray (5Y 5/2), and greenish gray (5GY 6/1) iron depletions; moderate medium subangular blocky structure; hard, slightly firm, very sticky and plastic; few fine and medium roots; few fine tubular pores; neutral (pH 7.2); abrupt wavy boundary. (0 to 13 inches thick)
Cg--43 to 46 inches; light gray (10YR 7/2) silt loam, black (N 2/0) faces of peds, olive gray (5Y 4/2) rubbed or crushed moist; many fine to large distinct pale yellow (2.5Y 7/4), light olive brown (2.5Y 5/4) and reddish brown (5YR 5/3) masses of iron accumulations moist; massive; very hard, firm, very sticky and plastic; few fine roots; few very fine pores; mildly alkaline (pH 7.5); clear smooth boundary. (0 to 8 inches thick)
2Cg--46 to 49 inches; very pale brown (10YR 7/3) sandy loam, dark brown (10YR 4/3) crushed moist; many fine to large distinct pale yellow (2.5Y 7/4) and yellow (2.5Y 7/6), and distinct and prominent olive brown (2.5Y 4/4) and olive (5Y 5/4, 5/6) masses of iron accumulations moist; massive; very hard, firm, slightly sticky and slightly plastic; neutral (pH 7.2); abrupt smooth boundary. (0 to 10 inches thick)
3Cg--49 to 51 inches; light brownish gray (10YR 6/2) sandy clay loam, dark brown (10YR 4/3) crushed moist; many fine to large distinct pale yellow (2.5Y 7/4), and faint and distinct dark brown (10YR 3/3) and yellowish brown (10YR 5/6) masses of iron accumulations moist; massive, hard, firm, sticky and slightly plastic; neutral (pH 7.2); abrupt smooth boundary. (0 to 4 inches thick)
4Cg--51 to 79 inches; light brownish gray (10YR 6/2) sandy loam, dark brown (10YR 4/3) moist; many medium distinct yellowish brown (10YR 5/6) mottles moist; massive; soft, very friable, nonsticky and nonplastic; neutral (pH 7.2).
TYPE LOCATION: Siskiyou County, California; about 17 miles Northeast of Weed on Hwy. 97, near the west edge of Grass Lake; 600 feet south and 400 feet west of the Northeast corner of sec. 21, T. 44 N., R. 3 W. Quad Location
RANGE IN CHARACTERISTICS: Depth to stratified alluvium is 40 to 60 inches. The mean annual soil temperature is 38 to 46 degrees F. The soil temperature exceeds 41 degrees F.
from early May 1 to mid November and exceeds 47 degrees F. from mid June to mid October. The soil between the depths of 6 and 18 inches is dry for 60 days from early August to early October and is moist in all or some part the rest of the year. The particle-size control section is 60 to 75 percent silt and very fine sand. Clay content is 18 to 25 percent in the upper part and 18 to 30 percent in the lower part of the particle-size control section. The mollic epipedon range from 22 to 40 inches thick. The soil is mottled below 9 inches. Organic carbon decreases irregularly with depth.
The A horizon ranges from very dark gray and gray to olive gray (10YR and 5Y 3/1, 3/2, 4/1, 4/2, 5/1, 5/2; N 3/0, N 4/0, N 5/0). Moist color ranges from black to dark olive gray (10YR and 5Y 2/1, 2/2, 3/1, 3/2; 2.5Y 3/2; N 2/0, N 3/0). It is silt loam, loam or silty clay loam, and is slightly acid or neutral and is 18 to 30 percent clay. Thickness of the A horizon ranges from 22 to 37 inches. Redoximorphic features range from few to common.
The C horizon ranges from gray, grayish brown and brown to pale olive and pale yellow (10YR and 5Y 5/1, 5/2, 5/3, 6/1, 6/2, 6/3, 7/1, 7/2, 7/3). Moist colors range from black to dark grayish brown and olive gray (10YR and 5Y 2/1, 2/2, 3/1, 3/2, 3/3, 4/1, 4/2). Redoximorphic features range from few to many, fine to large and faint to prominent. It is neutral or mildly alkaline.
The upper part of the C horizon is weakly to strongly gleyed. It is loam, silt loam, silty clay loam, clay loam and sandy clay loam and clay content ranges from 18 to 30 percent. The lower part of the C horizon is stratified sandy loam, fine sandy loam, sandy clay loam or very gravelly sandy clay loam and clay content ranges from 15 to 30 percent. Thin sand strata are in the lower part of the C horizon in some pedons. Rock fragments range from 0 to 60 percent and are mostly gravel size.
COMPETING SERIES: These are the Fury and Quam series. Fury soils have 27 to 35 percent clay in the control section and distinct or prominent mottles beginning at a depth of 5 to 10 inches. They also lack a C horizon. Quam soils have segregated carbonates at a depth below 20 inches.
GEOGRAPHIC SETTING: Esro soils are in basins and on basin terraces, low stream terraces and fans. They formed in alluvium from extrusive igneous rock and volcanic ash. Slopes are mostly less than 2 percent. Elevations are 4,500 to 6,200 feet. The climate is continental and subhumid with warm dry summers and cold moist winters. Mean annual precipitation is 20 to 40 inches. Snowfall is 10 to 20 inches. Mean January temperature is about 26 degrees F.; mean July temperature is 63 degrees F. Mean annual temperature is 41 to 46 degrees F. Frost-free period is 50 to 90 days.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the Avis, Iller, Odas, Oosen, Orset, Serpa and Sheld soils. Avis, Iller, Oosen and Sheld soils are well drained or somewhat excessively drained and have an ashy or a medial control section. Orset soils have an ochric epipedon and a coarse-loamy control section. Odas soils are coarse-loamy. Serpa soils have a fine textured argillic horizon.
DRAINAGE AND PERMEABILITY: Very poorly drained; slow or ponded runoff; moderately slow permeability. The soils are rare to frequently rare to flooded for periods of 1 to 3 months from January to July. The water table fluctuates from the surface to depths greater than 48 inches throughout the year. The water table is usually at the surface to a depth of 12 inches from December through August. During the months of September, October and November the water table drops to a depth of 12 to 20 inches. In areas that are less wet flooding is rare and the water table ranges to depth of 24 to 48 inches during December through July and from 48 to below 60 inches during the rest of the year.
USE AND VEGETATION: Used for livestock grazing. It is grazed during the summer months. The vegetation is tufted hairgrass, northern mannagrass, clover and other hygrophytic plants.
DISTRIBUTION AND EXTENT: Basins and drainageways of the Cascade Range in North Central California. The series is not extensive. MLRA is 22.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Davis, California
SERIES ESTABLISHED: Siskiyou County, California, 1978.
REMARK: Diagnostic horizons and features recognized in this pedon are:
Molloc epipedon- The zone from 0 to 32 inches (A1,A2,A3,)
Aquic soil moisture regime.
Andic Properties are assumed because most of the geographically associated soils are either Andisols or influenced by amorphous materials.