LOCATION MONSERATE CAEstablished Series
TAXONOMIC CLASS: Fine-loamy, mixed, superactive, thermic Typic Durixeralfs
TYPICAL PEDON: Monserate sandy loam - pasture, formerly cultivated. (Colors are for dry soil unless otherwise noted.)
Ap--0 to 5 inches; brown (7.5YR 5/4) sandy loam, dark reddish brown (5YR 3/4) moist; moderate medium granular structure; slightly hard, friable, nonsticky, nonplastic; many fine roots; many fine tubular pores; slightly acid (pH 6.2); clear smooth boundary. (5 to 9 inches thick)
A3--5 to 10 inches; yellowish red (5YR 4/6) sandy loam, dark reddish brown (2.5YR 3/4) moist; moderate medium subangular blocky structure; hard, firm, slightly sticky, slightly plastic; common fine roots; many fine tubular pores; slightly acid (pH 6.5); abrupt smooth boundary. (5 to 7 inches thick)
B21t--10 to 20 inches; reddish brown (5YR 4/4) sandy clay loam, dark reddish brown (2.5YR 3/4) moist; strong medium prismatic structure; extremely hard, very firm, very sticky, very plastic; few fine, mostly exped roots; few fine tubular pores; many moderately thick clay films lining pores and on faces of peds; neutral (pH 6.7); gradual smooth boundary. (5 to 12 inches thick)
B22t--20 to 28 inches; reddish brown (5YR 5/4) sandy clay loam, dark reddish brown (5YR 3/4) moist; strong medium angular blocky structure; extremely hard, very firm, very sticky, very plastic; few fine, mostly exped roots; few fine tubular pores; many moderately thick clay films lining pores and on faces of peds; neutral (pH 7.2); abrupt wavy boundary. (5 to 12 inches thick)
Clsim--28 to 45 inches; dark brown (10YR 4/3), dark reddish brown (5YR 3/4) moist; massive; indurated and extremely hard, very firm; when crushed has the appearance of loamy sand and is slightly sticky and nonplastic; very few roots in seams and fissures; slightly alkaline (pH 7.7); gradual smooth boundary. (5 to 20 inches thick)
C2si--45 to 57 inches; dark yellowish brown (10YR 3/4) loamy coarse sand, dark reddish brown (5YR 3/4) moist; massive and weakly cemented; very hard, firm, nonsticky, nonplastic; slightly alkaline (pH 7.6); clear wavy boundary. (3 to 18 inches thick)
C3--57 to 70 inches; yellowish brown (10YR 5/4) loamy coarse sand, dark reddish brown (5YR 3/4) moist; massive and weakly cemented in lenses; loose, nonsticky, nonplastic; slightly alkaline (pH 7.5). (Many feet thick)
TYPE LOCATION: Riverside County, California; about 2 miles east of Sunnymead; approximately 1,200 feet east and 150 feet north of the SW corner sec. 33, T.2S., R.3W.
RANGE IN CHARACTERISTICS: The mean annual soil temperature at a depth of 20 inches is about 65 degrees F. and the soil temperature usually is not below 47 degrees F. at any time. Soil between the depths of about 8 and 20 inches is usually moist in some or all parts from December to about the middle of May and usually is dry all the rest of the year. Rock fragments, mostly mineral grains 2 to 5 mm. in diameter, range from 5 to 35 percent and tend to be more numerous in the lower part of the profile.
The A horizon is grayish brown, brown, reddish brown or yellowish red, and the hue is 10YR, 7.5YR or 5YR. It is sandy loam or loam and is neutral or slightly acid. This horizon has granular or subangular blocky structure or it is hard or very hard and massive when dry. The average organic matter is less than 1 percent.
The B2t horizon is brown or strong brown in 7.5YR hue or reddish brown or dark reddish brown in 5YR hue. It is sandy clay loam or less commonly clay loam and contains 27 to 35 percent clay. The upper boundary of the B2t horizon is abrupt and contains at least 10 percent more clay absolute than the overlying horizon. Some pedons have a very thin A2 horizon. The B2t horizon has moderate to strong prismatic or angular blocky structure and usually the prismatic structure is in the upper part grading to angular blocky in the lower part. It is slightly acid to neutral and base saturation is 75 to 95 percent.
The upper Csim horizon is indurated and the upper surface has a smooth opal coating on more than half of the area. Other parts of the Csi horizon are strongly cemented, but layered and variable and some plates are indurated. It is neutral or mildly alkaline. The lower boundary of the main Csi horizon is smooth or wavy and highly irregular with silica apparently moving down along vertical planes into unconsolidated sediments. Dendritic deposits of manganese oxide and small amounts of calcium carbonate are in fracture planes in some pedons. Holes or "windows" occur in the pan. The lower part of the C horizon is neutral to moderately alkaline.
COMPETING SERIES: These are the Arlington, Buchenau, Buren, Exeter, Gloria, Igo, Redding, Rocklin, San Joaquin, and Ysidora series. Arlington, Buren, and Ysidora soils lack strong cementation in the duripans. Buchenau soils are calcareous in the B2t horizon and have lime and silica cementation. Exeter and Rocklin soils have less than 27 percent clay in the argillic horizon. (See Remarks.) Gloria, Redding, and San Joaquin soils have more than 35 percent clay in the argillic horizon. Igo soils are 3 to 12 inches deep to a duripan.
GEOGRAPHIC SETTING: The Monserate soils are on nearly level to moderately steep old dissected terraces and fans at elevations of 700 to 2,500 feet. The soils formed in alluvium derived principally from granitic rocks. The climate is dry subhumid mesothermal with long dry summers and mild moist winters. Mean annual precipitation is 12 to 18 inches. Average January temperature is 48 degrees to 52 degrees F., average July temperature is about 78 degrees F., and the mean annual temperature is 62 degrees to 65 degrees F. The freeze-free season is 230 to 280 days.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the Fallbrook, Greenfield, Hanford, Placentia, Ramona, and Vista soils. These soils lack duripans. Fallbrook and Vista soils have a paralithic contact. Hanford soils lack an argillic horizon. Greenfield soils have less than 18 percent clay in the argillic horizon. Placentia soils have a fine textured natric horizon.
DRAINAGE AND PERMEABILITY: Moderately well to well drained; slow to rapid runoff; permeability is moderately slow in the B2t horizon and very slow in the duripan.
USE AND VEGETATION: Used principally for growing grain, grain hay or pasture, some citrus, and field and truck crops when irrigation water is available. Naturalized vegetation is mainly annual grasses and forbs, widely spaced native canyon oak, and shrubs on eroded slopes.
DISTRIBUTION AND EXTENT: Interior valleys in the western part of southern California. The soils are of moderate extent.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Davis, California
SERIES ESTABLISHED: San Diego County (Oceanside Area), California, 1929.
REMARKS: The Monserate soils were formerly classified as Noncalcic Brown soils. The differentiae of the Exeter and Rocklin soils need further study.
The activity class was added to the classification in January of 2003. Competing series were not checked at that time. - ET
OSED scanned by SSQA. Last revised by state on 10/72.