LOCATION ROSSMOOR CAEstablished Series
TAXONOMIC CLASS: Coarse-loamy, mixed, superactive, thermic Fluventic Haploxerolls
TYPICAL PEDON: Rossmoor fine sandy loam - on a 2 percent smooth northeast facing slope at an elevation of 65 feet under annual grasses, Bermuda grass and forbs. When described February 7, 1984, the soil was moist throughout. (Colors are for dry soil unless otherwise stated).
A--0 to 6 inches; brown (10YR 5/3) fine sandy loam, dark brown (10YR 3/3) moist; massive; slightly hard, very friable, nonsticky and nonplastic; many very fine roots; few very fine tubular and common very fine interstitial pores; neutral (pH 6.8); gradual smooth boundary. (5 to 16 inches thick)
AC--6 to 29 inches; yellowish brown (10YR 5/4) fine sandy loam, dark brown (10YR 3/3) moist; massive; slightly hard, very friable, nonsticky and nonplastic; common very fine roots; many very fine interstitial pores; neutral (pH 7.0); diffuse smooth boundary. (12 to 25 inches thick)
C1--29 to 52 inches; yellowish brown (10YR 5/4) fine sandy loam, dark yellowish brown (10YR 3/4) moist; massive; hard, very friable, nonsticky and nonplastic; many very fine interstitial pores; neutral (pH 7.0); diffuse smooth boundary.
C2--52 to 62 inches; brown (10YR 4/3) fine sandy loam, dark yellowish brown (10YR 3/4) moist; massive; slightly hard, very friable, nonsticky and nonplastic; many very fine interstitial pores; neutral (pH 7.0); (combined thickness of C horizons is 25 to 40 inches)
TYPE LOCATION: Sacramento County, California, about 1.2 miles east of Rancho Cordova, 3,200 feet north and 4,400 feet west of the intersection of Folsom Blvd. and Coloma Road, 10 feet east of a farm road in a southwest field corner in an unsectionized area, T.9 N., R.6 E.; 38 degrees 35' 52" N Latitude, 121 degrees 19' 5" W Longitude.
RANGE IN CHARACTERISTICS: The mean annual soil temperature is 64 to 67 degrees F at 20 inches and remains above 47 degrees F throughout the year. The soil is dry between 7 inches and 23 inches in most years from May 15 to October 15, moist in all parts from December 1 to May 1 and moist in some part the rest of the year. Weighted average clay content of the textural control section is 5 to 15 percent. Content of fine sand and coarser materials is greater than 45 percent. This soil lacks stratification and organic matter decreases regularly with depth. Organic matter is 1 to 2 percent at a depth of 60 inches or more. Content of gravel is 0 to 3 percent throughout. Reaction is neutral to mildly alkaline throughout. Thickness of the mollic epipedon is 7 to 16 inches.
The A horizon is 10YR 5/4, 5/3, or 5/2. Moist color is 10YR 3/3, or 3/2. Clay content is 5 to 15 percent. Organic matter is 2 to 3 percent.
The C horizon is 10YR 6/4, 5/4, or 4/3. Moist color is 10YR 3/3 or 3/4. Texture is fine sandy loam or sandy loam with 5 to 15 percent clay content.
COMPETING SERIES: These are the Arroyo Seco, Goleta, Kelsey and Pico series. These series are stratified and organic matter decreases irregularly with depth.
GEOGRAPHIC SETTING: The Rossmoor soils are on high flood plains at elevations of 30 to 110 feet. Slopes are 0 to 2 percent. The soils formed in alluvium derived from mixed rock sources. Climate is characterized by hot dry summers and cool moist winters. Mean annual precipitation is 17 to 22 inches. Mean annual temperature is about 61 to 62 degrees F. Average January temperature is 46 degrees F and average July temperature is 76 degrees F. The freeze free season is 275 to 300 days.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the Columbia soils. Columbia soils have an ochric epipedon and are stratified.
DRAINAGE AND PERMEABILITY: Well drained; slow runoff; moderately rapid permeability. The construction of a system of levees and upstream dams has reduced the hazard of flooding. With this protection, the hazard of flooding is rare.
USE AND VEGETATION: Used for urban development, recreation and irrigated crops. Among the crops grown are alfalfa and annual grains. Native vegetation is uncultivated areas consists of valley oak, annual grasses and forbs.
DISTRIBUTION AND EXTENT: High floodplains along the American River in the Sacramento Valley. The series is of small extent.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Davis, California
SERIES ESTABLISHED: Sacramento County, California, 1987.
REMARKS:
Diagnostic horizon and features recognized in this pedon are:
Mollic epipedon - the zone from the surface to 7 inches (A, AC horizons). Organic matter is 1 percent more than the C.
Fluventic subgroup - organic matter is 1.2 percent at a depth of 60 inches and decreases regularly with depth.
Last revised by the state on 2/91.
The activity class was added to the classification in February of 2003. Competing series were not checked at that time. - ET