LOCATION MERRITT CAEstablished Series
TAXONOMIC CLASS: Fine-silty, mixed, superactive, thermic Fluvaquentic Haploxerolls
TYPICAL PEDON: Merritt silty clay loam - on a northwest facing slope of less than 1 percent in irrigated row crops at 4 feet elevation. (Colors are for dry soil unless otherwise noted.)
Ap--0 to 10 inches; gray (5Y 5/1) silty clay loam, very dark gray (5Y 3/1) moist; moderate medium subangular blocky structure; hard, friable, sticky and plastic; many very fine and fine roots; few very fine interstitial and tubular pores; strongly effervescent with disseminated lime; moderately alkaline (pH 8.4); clear smooth boundary. (8 to 10 inches thick)
Bk1--10 to 18 inches; grayish brown (2.5Y 5/2) silty clay loam, very dark grayish brown (2.5Y 3/2) moist; moderate medium subangular blocky structure; hard, friable, slightly sticky and slightly plastic; common very fine vertical roots; common very fine, fine and medium tubular pores; violently effervescent with disseminated lime, fine and medium lime concretions; moderately alkaline (pH 8.4); clear wavy boundary. (6 to 10 inches thick)
Bk2--18 to 27 inches; light brownish gray (2.5Y 6/2) silt loam, dark grayish brown (2.5Y 4/2) moist; common fine distinct grayish brown (10YR 5/2) mottles, dark brown (10YR 3/3) moist; massive; hard, friable, slightly sticky and slightly plastic; common very fine roots; common very fine and medium tubular pores; violently effervescent with disseminated lime and fine filaments and threads of light gray (5Y 7/1) lime dry; moderately alkaline (pH 8.4); clear irregular boundary. (4 to 12 inches thick)
C1-27 to 42 inches; mottled light olive gray (5Y 6/2) and light yellowish brown (10YR 6/4) very fine sandy loam, olive gray (5Y 5/2), dark grayish brown (2.5Y 4/2) and dark brown (10YR 4/3) moist; few fine prominent yellowish brown (10YR 5/6) mottles moist; massive, slightly hard, very friable, slightly sticky and slightly plastic; few very fine roots; common very fine, fine and medium tubular pores; very slightly effervescent with disseminated lime; moderately alkaline (pH 8.0); clear wavy boundary. (8 to 17 inches thick)
C2-42 to 54 inches thick; mottled gray (5Y 6/1), pale brown (10YR 6/3) and strong brown (7.5YR 5/6) fine sandy loam, olive gray (5Y 5/2), dark brown (10YR 4/3) and brown (7.5YR 4/4) moist; massive; slightly hard, very friable, nonsticky and nonplastic; few very fine vertical and oblique roots; common very fine and medium tubular pores; mildly alkaline (pH 7.5); clear smooth boundary. (0 to 15 inches thick)
Cg1--54 to 70 inches; light olive gray (5Y 6/2) fine sandy loam, dark greenish gray (5GY 4/1) moist; many medium prominent yellowish red (5YR 5/8) mottles, olive gray (5Y 5/2) and reddish brown (5YR 4/4) moist; massive; slightly hard, very friable, nonsticky and nonplastic; few very fine roots; common very fine and medium tubular pores; mildly alkaline (pH 7.5); abrupt wavy boundary. (0 to 18 inches thick)
Cg2--70 to 74 inches; greenish gray (5GY 6/1) fine sandy loam, dark greenish gray (5G 4/1) moist; common medium distinct light olive brown (2.5Y 5/4) mottles; massive; slightly hard, very friable, nonsticky and nonplastic; moderately alkaline (pH 8.2)
TYPE LOCATION: Yolo County, California; 1.5 miles north and .4 mile east of Clarksburg; sec. 23, T. 7 N., R. 4 E., MDB&M, projected. Clarksburg Quad.
RANGE IN CHARACTERISTICS: The mean soil temperature at a depth of 20 inches is between 60 degrees and 65 degrees F. and the soil temperature does not go as low as 41 degrees F. The control section between depths of 10 and 40 inches has 18 to 30 percent clay and averages less than 15 percent material coarser than very fine sand. Pebble-size fragments make up less than 5 percent of the soil. The soils between depths of 4 and 12 inches are dry from mid June until early November and are moist in some or all parts the rest of the year. The soils are calcareous in some or all parts between depths of 10 and 40 inches and may be calcareous above depths of 10 inches and below a depth of 40 inches. Some pedons are saline or saline-sodic.
The A horizon has colors of 10YR 5/2, 5/1, 4/1; 2.5Y 5/2; 5Y 5/2 or 5/1. Moist colors are 10YR 3/2, 3/1, 2/1; 2.5Y 3/2, 2/2; 5Y 3/2, 3/1 or 3/1. This horizon ranges from neutral to moderately alkaline. It contains 1 to 4 percent organic matter which decreases irregularly with depth. It has granular or subangular blocky structure. It is loam, silt loam or silty clay loam.
The Bk horizon has colors of 10YR 6/2, 5/2, 2.5Y 6/2 or 5/2. Moist colors are 10YR 5/2, 4/3, 4/2, 3/3; 2.5Y 5/2, 4/2; 5Y 5/2 or 4/2. It has distinct or prominent mottles in 7.5YR, 10YR or 2.5Y hues. It is silt loam or silty clay loam. This horizon is effervescent with disseminated and segregated lime.
The C or C' horizon has colors of 10YR 6/4, 6/3, 6/2, 5/2; 2.5Y 6/4; 5Y 6/2 or 6/1. Moist colors are 7.5YR 4/4; 10YR 4/3, 3/3; 2.5Y 4/3, 4/2; or 5Y 5/2. It has distinct or prominent mottles. It is stratified but the most common texture is very fine sandy loam. It is mainly moderately alkaline but some pedons are strongly alkaline with pH ranges of 8.8 to 9.0.
Ab horizons may be present in some pedons below the C horizon and have the same colors, texture and reaction as the A horizon.
Where present, the Cg horizon, below 40 inches, has colors of 2.5Y 5/2; 5Y 5/2; N5/0; 5Y 6/2; 5GY 6/1, 5/1; or 5G 5/1. Moist colors are 2.5Y 4/2; 5Y 4/2; N4/0, 5GY 4/1; or 5G 4/1. It has distinct or prominent mottles. It is stratified ranging from loamy fine sand to clay. These horizons are moderately alkaline to strongly alkaline.
COMPETING SERIES: There are no other soils in this family.
GEOGRAPHIC SETTING: Merritt soils are on nearly level recent alluvial fans and flood plains at elevations of 5 feet below sea level to 60 feet above. The soils formed in mixed alluvium from sedimentary formations. The climate is dry subhumid, mesothermal with hot dry summers and cool moist winters. Mean annual precipitation is 13 to 19 inches. The average January temperature is 45 degrees F., average July temperature is 75 degrees F., and the mean annual temperature is is 60 to 61 degrees F. The frost-free period is 270 to 300 days.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the Maria, Sacramento, Sycamore, Tyndall and Valdez soils. Sycamore soils have ochric epipedons due to organic matter being less than 1 percent. Sacramento soils have 45 to 60 percent clay in the 10 to 40 inch section. Maria soils have ochric epipedons. Tyndall soils average less than 18 percent clay in the 10 to 40 inch section. Valdez soils have ochric epipedons.
DRAINAGE AND PERMEABILITY: Poorly drained; slow runoff; moderately slow permeability.
USE AND VEGETATION: The soils are under intensive cultivation and are irrigated, producing a wide variety of field and row crops.
DISTRIBUTION AND EXTENT: The soil occurs in the Lower Sacramento and San Joaquin Valleys near the Sacramento Valley near the Sacramento and San Joaquin Rivers. The series is moderately extensive in MLRA-17,16,14.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Davis, California
SERIES ESTABLISHED: Yolo County, California, 1971.
REMARKS: Diagnostic horizons and features recognized in this pedon are:
Mollic epipedon - the zone from the surface to a depth of 18 inches (Ap,Bk)