LOCATION GRANDBEND CAEstablished Series
TAXONOMIC CLASS: Coarse-loamy, mixed, superactive, thermic Oxyaquic Haploxerolls
TYPICAL PEDON: Grandbend loam on a south facing slope of less than 1 percent in a cultivated field at an elevation of 45 feet. (Colors are for dry soil unless otherwise stated.)
Ap--0 to 16 inches; grayish brown (10YR 5/2) loam; very dark grayish brown (10YR 3/2) moist; weak medium subangular blocky structure; slightly hard, very friable, slightly sticky, slightly plastic; common very fine roots; common very fine interstitial pores; neutral (pH 6.9); abrupt smooth boundary.
C1--16 to 27 inches; pale brown (10YR 6/3) loam, dark brown (10YR 3/3) moist; dry; weak medium subangular blocky structure; slightly hard, very friable, slightly sticky, slightly plastic; common very fine roots; common very fine interstitial pores; slightly alkaline (pH 7.4); gradual smooth boundary.
C2--27 to 44 inches; light brownish gray (2.5Y 6/2) sandy loam, dark brown (10YR 3/3) moist; weak medium subangular blocky structure; slightly hard, very friable, slightly sticky, slightly plastic; common very fine roots; common very fine interstitial pores; few fine prominent light olive brown (2.5Y 5/6) masses of iron accumulations; slightly alkaline (pH 7.5); clear smooth boundary.
C3--44 to 54 inches; light brownish gray (2.5Y 6/2) silt loam; dark grayish brown (10YR 4/2) moist; weak medium subangular blocky structure; slightly hard, friable, slightly sticky, slightly plastic; common very fine roots; common very fine interstitial pores; common medium prominent light olive brown (2.5Y 5/4), and light yellowish brown (2.5Y 6/4) masses of iron accumulations; slightly alkaline (pH 7.4); abrupt smooth boundary.
2Ab--54 to 64 inches; dark gray (10YR 4/1) silty clay loam, black (N 2/0) moist; weak fine subangular blocky structure parting to weak medium subangular blocky; hard, firm, slightly sticky, moderately plastic; common very fine roots; few very fine tubular pores; common fine prominent pale yellow (2.5Y 7/4) masses of iron accumulations; slightly alkaline (pH 7.3); clear smooth boundary.
2Bb--64 to 67 inches; gray (5Y 5/1) silty clay loam, very dark gray (5Y 3/1) moist; weak fine subangular blocky structure parting to weak medium subangular blocky; hard, firm, slightly sticky, moderately plastic; few very fine roots; few very fine tubular pores; few fine faint light yellowish brown (2.5Y 6/4) masses of iron accumulations; slightly alkaline (pH 7.2).
TYPE LOCATION: Colusa County, California; about 2.25 miles southeast of the town of Grimes; 1250 feet east and 300 feet south of the northwest corner of section 15, T.14N, R.1E,MDB&M; 39 degrees 03 minutes 28 seconds N Latitude, 121 degrees 51 minutes 07 seconds W Longitude; USGS Tisdale Weir CA quadrangle.
RANGE IN CHARACTERISTICS: The mean annual soil temperature is 63 to 65 degrees F and the soil temperature is not below 47 degrees F at any time. The soil between the depths of 6 and 18 inches is dry in all parts from May 15 to October 31 and moist in some part from November 1 to May 15. Weighted average clay content of the 10 to 40 inch textural control section ranges from 8 to 17 percent clay. Depth to 2Ab horizon ranges from 40 to greater than 60 inches and does not occur in all profiles.
The Ap horizon has dry color of 10YR 5/2, 5/3; 2.5Y 5/2 and moist color of 10YR 3/3, 3/2 or 2.5Y 3/2. Reaction is neutral.
The C horizon has dry color of 10YR 6/3, 5/3; 2.5Y 6/2 and moist color of 10YR 3/3, 4/3, 5/3 or 2.5Y 3/2, 4/2. Texture is stratified sandy loam to silt loam. Reaction is slightly alkaline.
The 2Ab horizon has dry color of 10YR 4/1, 5/1, 6/1; 2.5Y 5/2 and moist color of 10YR 2/1, 3/1, 4/1 or N2/0 or 2.5Y 6/2, 4/2. Texture is silty clay loam. Reaction is neutral.
The 2Bb horizon has dry color of 5Y 5/1 and moist color of 5Y 3/1 or 2.5Y 4/2. Texture is silty clay loam. Reaction is neutral.
COMPETING SERIES: There are no competing series at this time.
GEOGRAPHIC SETTING: Grandbend soils are on nearly level floodplains at elevations of 25 to 55 feet. The soils formed in mixed alluvium. The climate has hot dry summers and cool moist winters with frequent fog. Mean annual precipitation varies from 14 to 16 inches. Average January temperature is about 45 degrees F; average July temperature is about 78 degrees F. Mean annual temperature is 60 to 62 degrees F. The frost-free season is 225 to 250 days.
GEOGRAPHICALLY ASSOCIATED SOILS: These are Vina, Corbiere, Scribner and Nueva soils. Vina soils have mollic epipedons greater than 50 cm thick. Corbiere soils have fine-silty over clayey textural control sections. Scribner soils have a fine-loamy textural control section and have a mollic epipedon greater than 50 cm. Nueva soils have a fine-loamy textural control section.
DRAINAGE AND PERMEABILITY: Somewhat poorly drained; negligable and low runoff; moderately slow permeability, some improvement of drainage has occurred due to levee and flood control structures on the Sacramento River. Water tables fluctuate with water levels in adjacent streams. A fluctuating water table occurs at depths of 2.5 to 4 feet from December thru March.
USE AND VEGETATION: Irrigated crops. Among the crops commonly grown are tomatoes, beans, safflower and wheat.
DISTRIBUTION AND EXTENT: Floodplain of the Sacramento River in the lower Sacramento Valley. The soils are not extensive. MLRA 17.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Davis, California
SERIES PROPOSED: Colusa County, SSA, 1994.
REMARKS:
Major Diagnostic Horizons:
1. Mollic Epipedon - 0 to 16 inches (Ap) ranges from 9 to 20 inches thick.
1.1 Organic matter is 1 to 3 percent.
Other Diagnostic Horizons or Soil Characteristics:
1. Coarse-loamy family: Fine sand and coarser sands range from 12 to 29 percent in the 10 to 40 inch textural control section.
2. Temperature - Moisture (Xeric-Thermic)
2.1 The 5 to 16 inch SMCS is dry in all parts from May 15 to October 31 and is moist in all parts from November 15 to May 1.
2.2 The soil temperature is above 47 degrees F. for the entire year.
2.3 The MAST is 63 to 65 degrees F.