LOCATION MOUNTMED CAEstablished Series
TAXONOMIC CLASS: Fine, smectitic, frigid Fluvaquentic Vertic Endoaquolls
TYPICAL PEDON: Mountmed peat, native meadow, on a less than 1 percent slope under sedges at 5,050 feet elevation. (When described, December 7, 1984, the soil was saturated throughout and the soil temperature at 20 inches was 46 degrees F. Colors are for dry soil unless otherwise noted).
Oi--0 to 6 inches; sphagnum peat; neutral (pH 6.8); abrupt smooth boundary. (0 to 6 inches thick)
A--6 to 16 inches; gray (5Y 5/1) clay, very dark gray (5Y 3/1) moist; few medium prominent light gray mottles (5GY 5/1) moist; weak coarse subangular blocky structure; very hard, very friable, very sticky and very plastic; many very fine and fine roots; few very fine interstitial pores; neutral (pH 7.0); clear wavy boundary. (10 to 13 inches thick)
Cg1--16 to 38 inches; light gray (5Y 6/1) clay, very dark gray (5Y 3/1) moist; many medium distinct greenish gray (5GY 5/1) mottles, dark greenish gray (5GY 4/1) moist; massive; very hard, very friable, very sticky and very plastic; few very fine and fine roots; few very fine interstitial pores; neutral (pH 7.0); clear wavy boundary.
Cg2--38 to 47 inches; pale yellow (2.5Y 7/4) clay loam, olive brown (2.5Y 4/4) moist; common fine prominent dark greenish gray (5GY 4/1) mottles, dry and moist; massive; very hard, very friable, sticky and plastic; few very fine and fine roots; few very fine interstitial pores; strongly effervescent; lime segregated in few medium soft filaments; mildly alkaline (pH 7.5); abrupt smooth boundary. (The combined thickness of the Cg horizons is 30 to 50 inches).
2C--47 to 55 inches; pale yellow (2.5Y 7/4) gravelly coarse sandy loam, light olive brown (2.5Y 5/4) moist; many medium prominent brownish yellow (10YR 6/6) mottles, dark yellowish brown(10YR 4/6) moist; massive; very hard, friable, nonsticky and nonplastic; few fine roots; many very fine interstitial pores; 20 percent pebbles; mildly alkaline (pH 7.5); abrupt smooth boundary. (0 to 8 inches thick)
3C--55 to 60 inches; light yellowish brown (10YR 6/4) sand, dark yellowish brown (10YR 4/4) moist; single grain; loose, nonsticky and nonplastic; no roots; many very fine interstitial pores; mildly alkaline (pH 7.5). (0 to 11 inches thick)
TYPE LOCATION: Lassen County, California; about 4.5 miles SE of Westwood; 4.5 miles E from Pine Town on Beaty and Associates logging road at the SE corner of its intersection with the road to the Home Ranch; about 1,400 feet E and 900 feet N of the SW corner of section 13, T.28 N., R.9 E.
RANGE IN CHARACTERISTICS: The mean annual soil temperature varies from 42 to 46 degrees F. The soil is saturated between the depths of 0 and 18 inches from November thru June and below 18 inches from July thru October unless drained. The soil temperature exceeds 41 degrees F from June 1 to December 15, and exceeds 47 degrees F from July 1 to December 1. Depth to the 2C horizon varies from 40 to more than 60 inches from the surface of the mineral soil. Depth to mottles is from the base of the mollic epipedon to a depth of 40 inches. Some pedons lack an O horizon. Some pedons lack secondary lime.
The A horizon is 10YR 5/1; 2.5Y 5/2; 5Y 5/1 or N 4/0. Moist color is 10YR 3/1, 2.5Y 3/2, 5Y 3/1 or N 2/0. It is loam, clay loam or clay.
The Cg horizon is 2.5Y 6/2, 6/4, 7/4; 5Y 5/1, 6/1, 6/2, 7/1; 5GY 7/1 or 6/1. Moist color is 2.5Y 4/2, 4/4; 5Y 3/1, 4/2, 5/1; 5GY 5/1 or 4/1.
The 2C horizon is 2.5Y 7/4 or 5G 7/1. Moist color is 2.5Y 5/4 or 5G 5/1. It is clay or coarse sandy loam modified by 15 to 20 percent 2 to 5 mm gravel and 10 to 50 percent 5 to 75 mm gravel. Reaction is neutral or mildly alkaline.
The 3 C horizon is 10YR 6/4 or 5GY 7/1. Moist color is 10YR 4/4 or 5GY 5/1. It is sand or sandy loam. Reaction is neutral or mildly alkaline.
COMPETING SERIES: These are the Dimmick and Fulda series. Both of these series have peak periods of precipitation in the spring and summer. Dimmick soils have mollic epipedons 14 to 30 inches thick and no rock fragments. Fulda soils have mollic epipedons 12 to 24 inches thick, no O horizon and have a B horizon.
GEOGRAPHIC SETTING: Mountmed soils are on fans and floodplains. Slopes are 0 to 3 percent. These soils formed in alluvium weathered from granitic and volcanic rocks. Elevation is 5,040 to 5,300 feet. The climate is subhumid with warm dry summers and cold moist winters. The mean annual precipitation is about 35 inches with 60 to 100 inches of snow. The mean annual temperature is about 44 degrees F., mean July temperature is about 60 degrees F. and mean January temperature is about 26 degrees F. The frost-free season is 60 to 80 days.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the Dotta, Keddie and Inville soils. Dotta soils are fine-loamy and have an argillic horizon. Keddie soils are fine-loamy and have a mollic epipedon more than 24 inches thick. Inville soils are loamy-skeletal and have an argillic horizon. Flooding is frequent for very brief to long periods during March through May.
DRAINAGE AND PERMEABILITY: Very poorly and poorly drained. The soil is saturated between the depths of 0 to 18 inches from November through June and below 18 inches from July through October unless drained. In drained phases the soil moisture control section (7 to 20 inches) is dry from August 1 to November 1 (90 days) and is moist in some or all parts the rest of the time. These phases are poorly or somewhat poorly drained. Runoff is very slow or ponded; slow permeability.
USE AND VEGETATION: Mountmed soils are used for pasture and rangeland. The vegetation is mainly sedges.
DISTRIBUTION AND EXTENT: Southwestern Lassen County, California. The soils of this series are moderately extensive.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Davis, California
SERIES ESTABLISHED: Lassen County, California, Susanville Area, parts of Lassen and Plumas County Soil Survey Area, 1988.
REMARKS: Diagnostic horizons and features recognized in this pedon are:
Mollic epipedon: 6 to 16 inches (A).